Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or Alum
sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like to
be able to just roll on some suitable adhesive over the full 4x6 area, and
press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate about
a 13% increase in stiffness, since stiffness is proportional to the square
of thickness, but ONLY if there is no slippage between the two layers.
Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I measured
that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply, so the
increase in stiffness is likely to be a bit more than 13%.

Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception of
things like nylon, delrin, other "greasy" plastics. Any opinions on this?
--
EA

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or
Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like
to be able to just roll on some suitable adhesive over the full 4x6 area,
and press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about a 13% increase in stiffness, since stiffness is proportional to the
square of thickness...

Proportional to the *cube* of thickness.

, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply,
so the increase in stiffness is likely to be a bit more than 13%.

Laminating materials with different Young's modulus is not generally
additive.


Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

If you're laminating on the neutral axis, the situation is not demanding.
White glue works fine for two layers of softwood, of equal thickness. Shear
loads are low.

When the lamination occurs off the neutral axis you have bigger shear loads
on the glue line, and they can be quite high.

Aluminum is a bugger to bond to if you need high strength. Commercially,
they use PAA -- phosphoric acid anodizing -- and you actually bond to the
anodizing, not the aluminum. I've described the "scratch-in" method of
getting a good bond to epoxy several times here. That would work, but it's
not practical for a big surface. It's good for small things.

When I have a question like that I get on the phone with 3M, Loctite, or one
of the other big guys, and keep bugging them until I get to an engineer who
knows what he's talking about. Ask about self-etching adhesives and adhesive
primers for aluminum. I've heard of them, but I don't know of any specifics.


Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception
of things like nylon, delrin, other "greasy" plastics. Any opinions on
this?

There are a blue million epoxy formulations. The common one that would be
reasonable in your application is an ordinary room-temperature-cure (RTC),
phenol-cured epoxy. In other words, boatbuilding epoxy. You probably have a
West Marine Supply (not WEST System) somewhere near Yonkers. We have them in
NJ. They carry common brands.

Epoxy is anti-thixotropic. In other words, it drools, unless it's modified
for surfacing.

When you price it, you'll probably realize that you're better off buying
overlaid plywood in the first place. If you want to paint it, MDO
(medium-density-overlay) plywood is fairly cheap and very smooth. Any lumber
supply that serves custom cabinet builders should have it. Don't get it wet
or you'll be sorry.

There are many other overlays available, including at least two thickness of
melamine (Formica, etc.). If print-through of the grain is an issue, make
sure it's either a thick overlay (MDO is thick enough), that it's a hard
material (like melamine), or it has a hardwood top veneer under the overlay.
Now you're getting into more costly stuff.

Good luck.

--
Ed Huntress


--
EA

On Mon, 11 Jul 2011 22:54:49 -0400, "Existential Angst"
wrote:

Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or Alum
sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like to
be able to just roll on some suitable adhesive over the full 4x6 area, and
press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate about
a 13% increase in stiffness, since stiffness is proportional to the square
of thickness, but ONLY if there is no slippage between the two layers.
Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I measured
that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply, so the
increase in stiffness is likely to be a bit more than 13%.

Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception of
things like nylon, delrin, other "greasy" plastics. Any opinions on this?

When I worked on diesel locomotive equipment, we used to use various types of
caulk to glue all the parts inside various chassis, such as transformers and
filter caps in power supplies. We did this because the vibration would break
everything loose - you would find large parts rolling around inside the chassis
if you didn't!

We started with official GE RTV sealant but eventually just bought household
silicon bath caulk at the hardware store because it was cheaper!! When you
needed to replace something it was easy to cut the stuff with a knife and pull
it off. We even used it on high voltage strobe lights.

We used that **** to glue everything!

On Mon, 11 Jul 2011 23:23:50 -0400, Ed Huntress wrote:

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full
4x6 area, and press them together, proly via weight plates. What would
good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about a 13% increase in stiffness, since stiffness is proportional to
the square of thickness...

Proportional to the *cube* of thickness.

, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than 13%.

Laminating materials with different Young's modulus is not generally
additive.

For 030 aluminum over 1/2" plywood the aluminum is going to carry most of
the tensile load from bending, which means that (a) the shear load at the
aluminum to plywood joint is going to be tremendous, and (b) the assembly
is going to be approximately as stiff as a 3/16" plate of aluminum
(because the cube root of 9/16 cubed minus 1/2 cubed is about equal to
3/8).

At least until the glue joint, or the underlying plywood, gives way.
Then it'll be a gawdaful mess.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Tim" wrote in message
...
On Mon, 11 Jul 2011 23:23:50 -0400, Ed Huntress wrote:

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full
4x6 area, and press them together, proly via weight plates. What would
good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about a 13% increase in stiffness, since stiffness is proportional to
the square of thickness...

Proportional to the *cube* of thickness.

, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than 13%.

Laminating materials with different Young's modulus is not generally
additive.

For 030 aluminum over 1/2" plywood the aluminum is going to carry most of
the tensile load from bending.....

Yeah, as long as it's on the tension side....

..., which means that (a) the shear load at the
aluminum to plywood joint is going to be tremendous, and (b) the assembly
is going to be approximately as stiff as a 3/16" plate of aluminum
(because the cube root of 9/16 cubed minus 1/2 cubed is about equal to
3/8).

At least until the glue joint, or the underlying plywood, gives way.
Then it'll be a gawdaful mess.

It doesn't sound like a good idea, does it? I wonder what kind of load EA is
thinking about, that he's concerned about bending stiffness.

--
Ed Huntress


--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than 13%.
Laminating materials with different Young's modulus is not generally
additive.
For 030 aluminum over 1/2" plywood the aluminum is going to carry most of
the tensile load from bending.....

Yeah, as long as it's on the tension side....

..., which means that (a) the shear load at the
aluminum to plywood joint is going to be tremendous, and (b) the assembly
is going to be approximately as stiff as a 3/16" plate of aluminum
(because the cube root of 9/16 cubed minus 1/2 cubed is about equal to
3/8).

At least until the glue joint, or the underlying plywood, gives way.
Then it'll be a gawdaful mess.

It doesn't sound like a good idea, does it? I wonder what kind of load EA is
thinking about, that he's concerned about bending stiffness.


No, it actually sounds like a very Bad Idea (tm).

Advice to OP, pick ONE material and use enough of it to handle the load.

And, unless you can match Boeing's aluminum bonding technology, don't.


--

Richard Lamb
http://www.home.earthlink.net/~cavelamb
http://www.home.earthlink.net/~sv_temptress

On Tue, 12 Jul 2011 01:06:07 -0400, Ed Huntress wrote:

"Tim" wrote in message
...
On Mon, 11 Jul 2011 23:23:50 -0400, Ed Huntress wrote:

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full
4x6 area, and press them together, proly via weight plates. What
would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will
generate about a 13% increase in stiffness, since stiffness is
proportional to the square of thickness...

Proportional to the *cube* of thickness.

, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than
13%.

Laminating materials with different Young's modulus is not generally
additive.

For 030 aluminum over 1/2" plywood the aluminum is going to carry most
of the tensile load from bending.....

Yeah, as long as it's on the tension side....

..., which means that (a) the shear load at the
aluminum to plywood joint is going to be tremendous, and (b) the
assembly is going to be approximately as stiff as a 3/16" plate of
aluminum (because the cube root of 9/16 cubed minus 1/2 cubed is about
equal to 3/8).

At least until the glue joint, or the underlying plywood, gives way.
Then it'll be a gawdaful mess.

It doesn't sound like a good idea, does it? I wonder what kind of load
EA is thinking about, that he's concerned about bending stiffness.

The plywood would keep the aluminum on the compression side from
buckling, for a while. Its kinda like an aluminum honeycomb between
solid sheet, with the plywood instead of the honeycomb.

If "light and stiff" are what he's looking for, it'd certainly deliver.
But when it let go it'd let go with a bang, and there's all sorts of
wrong with trying to bond wood to metal.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Tim" wrote in message
...
On Tue, 12 Jul 2011 01:06:07 -0400, Ed Huntress wrote:

"Tim" wrote in message
...
On Mon, 11 Jul 2011 23:23:50 -0400, Ed Huntress wrote:

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full
4x6 area, and press them together, proly via weight plates. What
would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will
generate about a 13% increase in stiffness, since stiffness is
proportional to the square of thickness...

Proportional to the *cube* of thickness.

, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than
13%.

Laminating materials with different Young's modulus is not generally
additive.

For 030 aluminum over 1/2" plywood the aluminum is going to carry most
of the tensile load from bending.....

Yeah, as long as it's on the tension side....

..., which means that (a) the shear load at the
aluminum to plywood joint is going to be tremendous, and (b) the
assembly is going to be approximately as stiff as a 3/16" plate of
aluminum (because the cube root of 9/16 cubed minus 1/2 cubed is about
equal to 3/8).

At least until the glue joint, or the underlying plywood, gives way.
Then it'll be a gawdaful mess.

It doesn't sound like a good idea, does it? I wonder what kind of load
EA is thinking about, that he's concerned about bending stiffness.

The plywood would keep the aluminum on the compression side from
buckling, for a while. Its kinda like an aluminum honeycomb between
solid sheet, with the plywood instead of the honeycomb.

If "light and stiff" are what he's looking for, it'd certainly deliver.
But when it let go it'd let go with a bang, and there's all sorts of
wrong with trying to bond wood to metal.

Christ, idn't ANYTHING simple, anymore??? Sheeesh.....
--
EA





--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

On Jul 12, 1:54*am, "Existential Angst" wrote:


For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full
4x6 area, and press them together, proly via weight plates. What
would good choices be? *How thick?


Christ, idn't ANYTHING simple, anymore??? * Sheeesh.....
--
EA

Without knowing what you are using the plywood and aluminum for it is
a little hard to provide good advise. But I suspect you could use
contact cement that is used to laminate formica on to particle board.
Be sure to clean the aluminum with sandpaper just before applying the
contact cement on the aluminum.

You put contact cement on both the aluminum and the plywood and let
dry until not tacky. Then cover the plywood with newspaper and then
put on the aluminum sheet. Get it aligned and then pull out the
newspaper and press on the aluminum sheet.

Dan

In article ,
says...

"Tim" wrote in message
...
On Tue, 12 Jul 2011 01:06:07 -0400, Ed Huntress wrote:

"Tim" wrote in message
...
On Mon, 11 Jul 2011 23:23:50 -0400, Ed Huntress wrote:

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full
4x6 area, and press them together, proly via weight plates. What
would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will
generate about a 13% increase in stiffness, since stiffness is
proportional to the square of thickness...

Proportional to the *cube* of thickness.

, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than
13%.

Laminating materials with different Young's modulus is not generally
additive.

For 030 aluminum over 1/2" plywood the aluminum is going to carry most
of the tensile load from bending.....

Yeah, as long as it's on the tension side....

..., which means that (a) the shear load at the
aluminum to plywood joint is going to be tremendous, and (b) the
assembly is going to be approximately as stiff as a 3/16" plate of
aluminum (because the cube root of 9/16 cubed minus 1/2 cubed is about
equal to 3/8).

At least until the glue joint, or the underlying plywood, gives way.
Then it'll be a gawdaful mess.

It doesn't sound like a good idea, does it? I wonder what kind of load
EA is thinking about, that he's concerned about bending stiffness.

The plywood would keep the aluminum on the compression side from
buckling, for a while. Its kinda like an aluminum honeycomb between
solid sheet, with the plywood instead of the honeycomb.

If "light and stiff" are what he's looking for, it'd certainly deliver.
But when it let go it'd let go with a bang, and there's all sorts of
wrong with trying to bond wood to metal.

Christ, idn't ANYTHING simple, anymore??? Sheeesh.....

Not if you're looking for "light and stiff".

If you want something light, stiff, and cheap and easy to make from
readily available materials, use pink foam insulation and bond 1/8"
plywood to each side with a structural-rated adhesive labelled for use
with foam (some structural adhesives use solvents that will dissolve
foam).

Home Depot and Lowes should have everything you need for small panels,
you may have to go to real lumber yard to get 1/8" ply in big panels.

The ply gives you the tension and compression members, the foam carries
the shear between them, and the foam takes glue well.

If you're going to need to put screws into it or bolts through it, cut
out the foam and put some solid wood blocks where the screws or bolts
will go.

For a neat job you can also put solid wood around the edges--pieces
milled from the spruce 2x3s that Home Depot sells work well for this and
are very light.

Don't trust anybody's life to it without making up a sample and testing
to destruction.

On Jul 12, 1:39*am, Tim wrote:
...
If "light and stiff" are what he's looking for, it'd certainly deliver. *
But when it let go it'd let go with a bang, and there's all sorts of
wrong with trying to bond wood to metal.

--
Tim Wescott

The temperature coefficients of expansion, for one.

jsw

"Jim Wilkins" wrote in message
...
On Jul 12, 1:39 am, Tim wrote:
...
If "light and stiff" are what he's looking for, it'd certainly deliver.
But when it let go it'd let go with a bang, and there's all sorts of
wrong with trying to bond wood to metal.

--
Tim Wescott

The temperature coefficients of expansion, for one.

jsw

That shouldn't be a big issue indoors. With wood, the big issue is expansion
and shrinkage from changes in humidity, even indoors, between seasons. If
you put an impermeable material on just one side, you're likely to have some
serious warping between seasons.

--
Ed Huntress

On Jul 11, 10:54*pm, "Existential Angst" wrote:

*Any opinions on this?

Yes. Many opinions. Just make sure that when laminating dissimilar
materials, to do both sides of the substrate, a 'balance' sheet.
Trying to get away without one is foolish. In case of laminate, just a
cheap discontinued colour will suffice.
Also, look into Wilsonart 3000 adhesive. Water based, will stick
anything to anything (other than greasy plastics).
Lots of open time and a decent roller which will allow your body
weight to do the work is all you need.
Wilsonart 3000 is NOT contact cement but works a bit like it. One side
of the joint has to have minimal porosity.

On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement. _________________

Contact cement would, I think, work well for 030 aluminum to one side of
1/4 plywood, where the wood would have a chance to flex. It may work on
1/2" plywood if the bond isn't heavily stressed. But I think you'd
overcome the strength of the bond if you tried it on both sides, and then
loaded things heavily.

'course, a quick look at yield strengths of Al and contact cement, plus
some calculations, would tell you what's what.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Tim" wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement. _________________

Contact cement would, I think, work well for 030 aluminum to one side of
1/4 plywood, where the wood would have a chance to flex. It may work on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!


But I think you'd
overcome the strength of the bond if you tried it on both sides, and then
loaded things heavily.

Iow, you advise against Robatoy's advice of laminating both sides?
Reason?


'course, a quick look at yield strengths of Al and contact cement, plus
some calculations, would tell you what's what.

4 ft x 6 ft is a lot of contact area. There will be some flex, but not like
bending anything into a U.
I'm thinking over a 4-6 ft dimension, occasional flex of mebbe an inch or
two.
--
EA






--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Existential Angst" wrote in message
...
"Tim" wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement. _________________

Contact cement would, I think, work well for 030 aluminum to one side of
1/4 plywood, where the wood would have a chance to flex. It may work on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.





But I think you'd
overcome the strength of the bond if you tried it on both sides, and then
loaded things heavily.

Iow, you advise against Robatoy's advice of laminating both sides?
Reason?


'course, a quick look at yield strengths of Al and contact cement, plus
some calculations, would tell you what's what.

4 ft x 6 ft is a lot of contact area. There will be some flex, but not
like bending anything into a U.
I'm thinking over a 4-6 ft dimension, occasional flex of mebbe an inch or
two.
--
EA






--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates, to
.030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like
to be able to just roll on some suitable adhesive over the full 4x6 area,
and press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about a 13% increase in stiffness, since stiffness is proportional to the
square of thickness...

Proportional to the *cube* of thickness.

Dayum.......



, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than 13%.

Laminating materials with different Young's modulus is not generally
additive.


Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

If you're laminating on the neutral axis, the situation is not demanding.
White glue works fine for two layers of softwood, of equal thickness.
Shear loads are low.

When the lamination occurs off the neutral axis you have bigger shear
loads on the glue line, and they can be quite high.

Aluminum is a bugger to bond to if you need high strength. Commercially,
they use PAA -- phosphoric acid anodizing -- and you actually bond to the
anodizing, not the aluminum. I've described the "scratch-in" method of
getting a good bond to epoxy several times here. That would work, but it's
not practical for a big surface. It's good for small things.

When I have a question like that I get on the phone with 3M, Loctite, or
one of the other big guys, and keep bugging them until I get to an
engineer who knows what he's talking about. Ask about self-etching
adhesives and adhesive primers for aluminum. I've heard of them, but I
don't know of any specifics.


Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception
of things like nylon, delrin, other "greasy" plastics. Any opinions on
this?

There are a blue million epoxy formulations. The common one that would be
reasonable in your application is an ordinary room-temperature-cure (RTC),
phenol-cured epoxy. In other words, boatbuilding epoxy. You probably have
a West Marine Supply (not WEST System) somewhere near Yonkers. We have
them in NJ. They carry common brands.

Epoxy is anti-thixotropic. In other words, it drools, unless it's modified
for surfacing.

When you price it, you'll probably realize that you're better off buying
overlaid plywood in the first place. If you want to paint it, MDO
(medium-density-overlay) plywood is fairly cheap and very smooth. Any
lumber supply that serves custom cabinet builders should have it. Don't
get it wet or you'll be sorry.

There are many other overlays available, including at least two thickness
of melamine (Formica, etc.). If print-through of the grain is an issue,
make sure it's either a thick overlay (MDO is thick enough), that it's a
hard material (like melamine), or it has a hardwood top veneer under the
overlay. Now you're getting into more costly stuff.

Good luck.

It appears ahm gonna need it!!
Unless some of the simple solutions turn out.
Also, effing .030 alum is not cheap!! 1/8" would cost on the order of $150,
while 1/32" costs $75!!!!!
Talk about non-linear pricing -- holy ****.....

..030 SS is of course worse: $150 for the piece, altho I didn't compare this
to 1/8". I suspect about as non-linear.
Heh, and the 1/2" ply costs.... $20???? LOL

Appreciate the overview.

Oh, I asked elsewhere, but what does "contact cement" specifically connote?
Is it a genre, like "two-part epoxy" or white glues? A few people have
recommended it. Just wondering if I should be looking at a specific type.
--
EA



--
Ed Huntress


--
EA

"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
"Tim" wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement. _________________

Contact cement would, I think, work well for 030 aluminum to one side of
1/4 plywood, where the wood would have a chance to flex. It may work on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?
If I'm right, do I get a prize??
--
EA







But I think you'd
overcome the strength of the bond if you tried it on both sides, and
then
loaded things heavily.

Iow, you advise against Robatoy's advice of laminating both sides?
Reason?


'course, a quick look at yield strengths of Al and contact cement, plus
some calculations, would tell you what's what.

4 ft x 6 ft is a lot of contact area. There will be some flex, but not
like bending anything into a U.
I'm thinking over a 4-6 ft dimension, occasional flex of mebbe an inch or
two.
--
EA






--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Existential Angst" wrote in message
...
"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates, to
.030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would
like to be able to just roll on some suitable adhesive over the full 4x6
area, and press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about a 13% increase in stiffness, since stiffness is proportional to
the square of thickness...

Proportional to the *cube* of thickness.

Dayum.......



, but ONLY if there is no slippage between the two layers.

Correct.

Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured that 1/4" alum plate is as stiff or stiffer than decent 1/2"
ply, so the increase in stiffness is likely to be a bit more than 13%.

Laminating materials with different Young's modulus is not generally
additive.


Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

If you're laminating on the neutral axis, the situation is not demanding.
White glue works fine for two layers of softwood, of equal thickness.
Shear loads are low.

When the lamination occurs off the neutral axis you have bigger shear
loads on the glue line, and they can be quite high.

Aluminum is a bugger to bond to if you need high strength. Commercially,
they use PAA -- phosphoric acid anodizing -- and you actually bond to the
anodizing, not the aluminum. I've described the "scratch-in" method of
getting a good bond to epoxy several times here. That would work, but
it's not practical for a big surface. It's good for small things.

When I have a question like that I get on the phone with 3M, Loctite, or
one of the other big guys, and keep bugging them until I get to an
engineer who knows what he's talking about. Ask about self-etching
adhesives and adhesive primers for aluminum. I've heard of them, but I
don't know of any specifics.


Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception
of things like nylon, delrin, other "greasy" plastics. Any opinions on
this?

There are a blue million epoxy formulations. The common one that would be
reasonable in your application is an ordinary room-temperature-cure
(RTC), phenol-cured epoxy. In other words, boatbuilding epoxy. You
probably have a West Marine Supply (not WEST System) somewhere near
Yonkers. We have them in NJ. They carry common brands.

Epoxy is anti-thixotropic. In other words, it drools, unless it's
modified for surfacing.

When you price it, you'll probably realize that you're better off buying
overlaid plywood in the first place. If you want to paint it, MDO
(medium-density-overlay) plywood is fairly cheap and very smooth. Any
lumber supply that serves custom cabinet builders should have it. Don't
get it wet or you'll be sorry.

There are many other overlays available, including at least two thickness
of melamine (Formica, etc.). If print-through of the grain is an issue,
make sure it's either a thick overlay (MDO is thick enough), that it's a
hard material (like melamine), or it has a hardwood top veneer under the
overlay. Now you're getting into more costly stuff.

Good luck.

It appears ahm gonna need it!!
Unless some of the simple solutions turn out.
Also, effing .030 alum is not cheap!! 1/8" would cost on the order of
$150, while 1/32" costs $75!!!!!
Talk about non-linear pricing -- holy ****.....

.030 SS is of course worse: $150 for the piece, altho I didn't compare
this to 1/8". I suspect about as non-linear.
Heh, and the 1/2" ply costs.... $20???? LOL

Appreciate the overview.

Oh, I asked elsewhere, but what does "contact cement" specifically
connote?

Rubber-based. Usually Neoprene family. Solvent-type can be a wide variety of
Neoprene-type rubbers. Water-based typically is polychloroproprene. Don't
ask me what the hell that is, except that it's related to Neoprene.

Is it a genre, like "two-part epoxy" or white glues?

It refers to glues that you usually apply to both surfaces, wait a bit, and
then press them together. You'll need a slip sheet of slick drafting paper
or something similar. Brown kraft paper will work. If you haven't done it,
look it up on YouTube and save yourself some grief.

The adhesive is somewhat air-impeded, like laminating polyester resin, so
the surface of each side is ready to stick when most of the solvent
evaporates.

But it's rubber, in the end.

A few people have recommended it. Just wondering if I should be looking
at a specific type.

Solvent-based usually is stronger, but don't count on that anymore. 3M
supplies some data on their formulations.

If you're counting on that bonded stiffness, and the panel stiffness that
results from making the structure thicker, that you were talking about
earlier, you won't get a lot of it with contact cement. But I think you're
chasing your tail on that issue, anyway. Again, it's a question of what your
application is.

--
Ed Huntress


--
EA

"Existential Angst" wrote in message
...
"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
"Tim" wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one side
of
1/4 plywood, where the wood would have a chance to flex. It may work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

If I'm right, do I get a prize??

When you're right, we'll consider it. d8-)

--
Ed Huntress


--
EA







But I think you'd
overcome the strength of the bond if you tried it on both sides, and
then
loaded things heavily.

Iow, you advise against Robatoy's advice of laminating both sides?
Reason?


'course, a quick look at yield strengths of Al and contact cement, plus
some calculations, would tell you what's what.

4 ft x 6 ft is a lot of contact area. There will be some flex, but not
like bending anything into a U.
I'm thinking over a 4-6 ft dimension, occasional flex of mebbe an inch
or two.
--
EA






--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
"Tim" wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica
laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for
large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid
Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one side
of
1/4 plywood, where the wood would have a chance to flex. It may work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

Well, in the case of pure flex, won't a thicker material flex less, thereby
introducing less force?
Seems like an optimization problem here.....
Also, by definition, distance from the neutral axis would have SOME
contribution, no?


If I'm right, do I get a prize??

When you're right, we'll consider it. d8-)

Will I get to specify her dimensions?
--
EA



--
Ed Huntress


--
EA







But I think you'd
overcome the strength of the bond if you tried it on both sides, and
then
loaded things heavily.

Iow, you advise against Robatoy's advice of laminating both sides?
Reason?


'course, a quick look at yield strengths of Al and contact cement,
plus
some calculations, would tell you what's what.

4 ft x 6 ft is a lot of contact area. There will be some flex, but not
like bending anything into a U.
I'm thinking over a 4-6 ft dimension, occasional flex of mebbe an inch
or two.
--
EA






--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Existential Angst" wrote in message
...
"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
"Ed Huntress" wrote in message
...

"Existential Angst" wrote in message
...
"Tim" wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm
curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica
laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for
large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid
Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one side
of
1/4 plywood, where the wood would have a chance to flex. It may work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

Well, in the case of pure flex, won't a thicker material flex less,
thereby introducing less force?

Thinner gives more, so it won't load the aluminum-to-wood bond as much.

Seems like an optimization problem here.....
Also, by definition, distance from the neutral axis would have SOME
contribution, no?

Let's not go there. We'd need pictures and I'm not up for it.



If I'm right, do I get a prize??

When you're right, we'll consider it. d8-)

Will I get to specify her dimensions?

And degrees of firmness. Do you prefer inflatable or foam-filled?

--
Ed Huntress




--
EA




But I think you'd
overcome the strength of the bond if you tried it on both sides, and
then
loaded things heavily.

Iow, you advise against Robatoy's advice of laminating both sides?
Reason?


'course, a quick look at yield strengths of Al and contact cement,
plus
some calculations, would tell you what's what.

4 ft x 6 ft is a lot of contact area. There will be some flex, but
not like bending anything into a U.
I'm thinking over a 4-6 ft dimension, occasional flex of mebbe an inch
or two.
--
EA






--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

On Jul 11, 8:54*pm, "Existential Angst" wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or Alum
sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: *when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like to
be able to just roll on some suitable adhesive over the full 4x6 area, and
press them together, proly via weight plates.
What would good choices be? *How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate about
a 13% increase in stiffness, since stiffness is proportional to the square
of thickness, but ONLY if there is no slippage between the two layers.
Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. *I measured
that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply, so the
increase in stiffness is likely to be a bit more than 13%.

Inyway, I'd like an idea of how to gauge the type of adhesive to
application. *Bang fer the buck is always good, as well.

Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception of
things like nylon, delrin, other "greasy" plastics. *Any opinions on this?
--
EA

If you want stiffness out of wood construction, look up "torsion
box". Can be scaled to whatever size you want.
I've seen the technique used for cantilevered shelves coming out of
walls with no supports.

Stan

On Jul 12, 11:30*am, "dadiOH" wrote:


Contact cement is hard to apply evenly and is messy: plan on throwing away
any roller/brush used for application.

You are also hoping the cheap roller isn't made with pile stuck into
an adhesive that the solvent in the contact cement doesn't dissolve.
That way the roller itself will unroll, and then you're in trouble.

*Porous surfaces will most likely
require two coats. *Each surface needs to look glossy all over and must be
dry enough so your finger doesn't stick.

Others have suggested using paper slip sheets.

Nooooo paper slip sheets... they can get caught and tear. Dowels 5/16"
or bigger.*

That will work but the thing
about contact cement is, well, it bonds on contact. *I prefer to use dowels
or sticks to keep the two surfaces well apart from each other until you are
ready to bond them. *I usually space them (dowels) 12-15" apart, depends on
the dowel diameter.

Once you start bonding, start at the center and work out toward the ends to
avoid trapping air. *Once all is bonded it needs to be *BONDED*. *Do that
with a J-roller, lots of pressure; again, work from center out to the ends
and edges. *You can also use a rubber mallet, roller is better.

J roller indeed. You obviously know your laminating stuff.

wrote in message
...
On Jul 11, 8:54 pm, "Existential Angst" wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or
Alum
sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like
to
be able to just roll on some suitable adhesive over the full 4x6 area, and
press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about
a 13% increase in stiffness, since stiffness is proportional to the square
of thickness, but ONLY if there is no slippage between the two layers.
Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured
that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply, so the
increase in stiffness is likely to be a bit more than 13%.

Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception
of
things like nylon, delrin, other "greasy" plastics. Any opinions on this?
--
EA

If you want stiffness out of wood construction, look up "torsion
box". Can be scaled to whatever size you want.
I've seen the technique used for cantilevered shelves coming out of
walls with no supports.

Stan

Torsion boxes are great, but if you follow the whole thread, it sounds like
he needs something much thinner.

--
Ed Huntress

On Jul 12, 11:12*am, "Existential Angst" wrote:

So how do you resolve the disparate opinion from Tim and Robatoy, ito of
symmetrical lamination?

I can't speak for Tim, but I have laminated elevator panels,
restaurant cabinets, bars, floors, walls, tables, countertops in a
variety of materials, back splashes, suspended ceiling sections,
valences.... I could go on.

The most stable 'packages' do not include MDF or plywood. When you
laminate onto plywood, your joint is only going to be as strong as
the next ply's adhesion to the ply below. You have no control over
that.
A quality particle board, and yes there are many, many grades
(hardwood, long fibre, different binders, densities etc.), when
laminated, will be a far better performer that a regular plywood,
again assuming properly laminated. In terms of strength, a proper
plywood (and there is a lot of **** out there) will be stronger, but
cost and the de-lamination problems which I have encountered over the
years doesn't make a plywood an automatic choice over PB. Proper High
Density PB is VERY impact resistant especially when clad in a GP grade
HPLAM.

I have used sprayed rubber contact cement for years and years and only
like the Imperial airless 32 lb cannisters, as the layer of adhesive
can be very thin and therefore not give you much slippage relative to
the laminate and substrate. Too much rubber contact cement and you
'disconnect' the laminate laterally from the base. It actually slides
ever so slightly even after it has cured. Wilsonart 3000 PVA does not
allow for slippage which can set up immense tension between the lam
and subs to the point that 0.125 acrylic with actually form hairline
cracks, so in that app, use rubber contact cement.

People I know are now using an MDF and/or PB which is water resistant,
but not as nutso-coo-coo as Extira waterproof... or expensive.

And ALWAYS ALWAYS use a balance sheet even IF you're going to screw
the 'half' package to a row of cabinets. For the little time and money
involved, it is simply silly NOT to. In two adjoining buildings, I
laminated the elevators panels in one building, my way, 15 years ago.
The other building's elevator (I didn't bid on that gig) has its
panels redone, at contractor's expense, after 2 years, THEN they did
use a balance sheet that time but cheaped out on post-form grade
laminate, thinking they'd save a few bucks. Within 6 months, they had
me do it that time. I billed them for materials only. The building's
owner added $ 500.00 for labour. (Not enough, mind you, but I got a
lot of referrals over the years from him.)

Shortcuts WILL bite you in the ass......like that time, I....nebber
mind...

On 07/12/2011 08:14 AM, Ed Huntress wrote:
"Existential wrote in message
...
"Ed wrote in message
...

"Existential wrote in message
...
wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic, inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one side
of
1/4 plywood, where the wood would have a chance to flex. It may work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

I dunno -- I was seeing it as the distance from the neutral axis. You
can't increase the distance from the neutral axis without increasing
volume, so they pretty much go together.

I was saying that if you only put the aluminum on _one side_, _and_ you
use something thinner than 1/2 inch, that you should be OK. Basically,
the aluminum is going to move a lot less than the wood. Only doing one
side gives the wood an opportunity to move (and to bow with humidity),
which relieves stress on the glue joint.

Put Al on both sides of the wood and you're right back to gluing a
strong thing to a weak thing with stuff of questionable strength -- so
if you stress it to breaking, either the glue bond or the underlying
wood is going to shear, or the glue on the compression side is going to
let the aluminum lift and buckle, or the wood on the compression side is
going to let the aluminum dig in and buckle.

But (again) if rigidity is more important than strength, this may not be
a bad way to go.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

In article ,
says...

wrote in message
...
On Jul 11, 8:54 pm, "Existential Angst" wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or
Alum
sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like
to
be able to just roll on some suitable adhesive over the full 4x6 area, and
press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about
a 13% increase in stiffness, since stiffness is proportional to the square
of thickness, but ONLY if there is no slippage between the two layers.
Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured
that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply, so the
increase in stiffness is likely to be a bit more than 13%.

Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception
of
things like nylon, delrin, other "greasy" plastics. Any opinions on this?
--
EA

If you want stiffness out of wood construction, look up "torsion
box". Can be scaled to whatever size you want.
I've seen the technique used for cantilevered shelves coming out of
walls with no supports.

Stan

Torsion boxes are great, but if you follow the whole thread, it sounds like
he needs something much thinner.

If he wants something fairly stiff, light, and about a half inch thick,
I'd say try bonding some 20" wide flashing to both sides of a piece of
1/2" foam insulation. Use a structural adhesive rated for foam and
aluminum. Point of failure will likely be shear in the foam. Same
caveats as with all foam core--if you need to put screws or bolts
through it, cut out the foam where they go and put in something solid.

And test the Hell out of it before trusting it in a situation in which
someone can get hurt.

On Jul 12, 1:11*pm, "J. Clarke" wrote:
In article ,
says...







wrote in message
....
On Jul 11, 8:54 pm, "Existential Angst" wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm curious about
laminating an approx. 4' x 6' area of plywood with some other thin-ish, or
even not so thin-ish material -- from formica laminates, to .030 SS or
Alum
sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for large-contact wood
areas, in building mezzanines in lofts, etc.
Then there is elmer's carpenter's/wood glue, mastics for tile (what's a
mastic, inyway??), epoxies, a zillion other adhesives.

The general Q is: when to use what for what?

For example, in the .030 SS/Alum I will place over 1/2" ply, I would like
to
be able to just roll on some suitable adhesive over the full 4x6 area, and
press them together, proly via weight plates.
What would good choices be? How thick?

Interestingly, an increase in thickness from ..5 to .532 will generate
about
a 13% increase in stiffness, since stiffness is proportional to the square
of thickness, but ONLY if there is no slippage between the two layers..
Thus, the requirement for full-surface bonding, via adhesive.

Ackshooly, that 13% inc in stiffness presumes similar materials. I
measured
that 1/4" alum plate is as stiff or stiffer than decent 1/2" ply, so the
increase in stiffness is likely to be a bit more than 13%.

Inyway, I'd like an idea of how to gauge the type of adhesive to
application. Bang fer the buck is always good, as well.

Along these lines, I see all kinds of two-part epoxies, specialized for
wood, metal, ceramics/glass, etc.
Afaict, they all work the same on everything, with perhaps the exception
of
things like nylon, delrin, other "greasy" plastics. Any opinions on this?
--
EA

If you want stiffness out of wood construction, look up "torsion
box". *Can be scaled to whatever size you want.
I've seen the technique used for cantilevered shelves coming out of
walls with no supports.

Stan

Torsion boxes are great, but if you follow the whole thread, it sounds like
he needs something much thinner.

If he wants something fairly stiff, light, and about a half inch thick,
I'd say try bonding some 20" wide flashing to both sides of a piece of
1/2" foam insulation. *Use a structural adhesive rated for foam and
aluminum. *Point of failure will likely be shear in the foam. *Same
caveats as with all foam core--if you need to put screws or bolts
through it, cut out the foam where they go and put in something solid.

And test the Hell out of it before trusting it in a situation in which
someone can get hurt.

Virtually NO impact resistance... maybe some in blunt impact...but...

On 07/12/2011 10:09 AM, Robatoy wrote:
On Jul 12, 11:12 am, "Existential wrote:

So how do you resolve the disparate opinion from Tim and Robatoy, ito of
symmetrical lamination?

I can't speak for Tim, but I have laminated elevator panels,
restaurant cabinets, bars, floors, walls, tables, countertops in a
variety of materials, back splashes, suspended ceiling sections,
valences.... I could go on.

Like I said, I was specifically addressing the oddball case of
laminating aluminum to plywood. It makes a really interesting
theoretical problem, and may even be practical for a homebuilt airplane,
if you need the strength and you're a hot-**** adhesive engineer, and
you keep it dry.

But it's not what EA wants.

The most stable 'packages' do not include MDF or plywood. When you
laminate onto plywood, your joint is only going to be as strong as
the next ply's adhesion to the ply below. You have no control over
that.
A quality particle board, and yes there are many, many grades
(hardwood, long fibre, different binders, densities etc.), when
laminated, will be a far better performer that a regular plywood,
again assuming properly laminated. In terms of strength, a proper
plywood (and there is a lot of **** out there) will be stronger, but
cost and the de-lamination problems which I have encountered over the
years doesn't make a plywood an automatic choice over PB. Proper High
Density PB is VERY impact resistant especially when clad in a GP grade
HPLAM.

I have used sprayed rubber contact cement for years and years and only
like the Imperial airless 32 lb cannisters, as the layer of adhesive
can be very thin and therefore not give you much slippage relative to
the laminate and substrate. Too much rubber contact cement and you
'disconnect' the laminate laterally from the base. It actually slides
ever so slightly even after it has cured. Wilsonart 3000 PVA does not
allow for slippage which can set up immense tension between the lam
and subs to the point that 0.125 acrylic with actually form hairline
cracks, so in that app, use rubber contact cement.

People I know are now using an MDF and/or PB which is water resistant,
but not as nutso-coo-coo as Extira waterproof... or expensive.

And ALWAYS ALWAYS use a balance sheet even IF you're going to screw
the 'half' package to a row of cabinets. For the little time and money
involved, it is simply silly NOT to. In two adjoining buildings, I
laminated the elevators panels in one building, my way, 15 years ago.
The other building's elevator (I didn't bid on that gig) has its
panels redone, at contractor's expense, after 2 years, THEN they did
use a balance sheet that time but cheaped out on post-form grade
laminate, thinking they'd save a few bucks. Within 6 months, they had
me do it that time. I billed them for materials only. The building's
owner added $ 500.00 for labour. (Not enough, mind you, but I got a
lot of referrals over the years from him.)

Shortcuts WILL bite you in the ass......like that time, I....nebber
mind...

Is there a particle board that has the bending strength that he needs
for his machine base? Oriented strand board ("chipboard", or "Crudboard
(TM)", as my dad used to call it) would -- but I could see it having the
same problem as plywood, with glue letting go in shear.

Or to stop looking at trees and to take a look at the forest -- is there
a way to start with plywood that has the strength that he wants, and
make it look good without laminating?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Tim Wescott" wrote in message
...
On 07/12/2011 08:14 AM, Ed Huntress wrote:
"Existential wrote in message
...
"Ed wrote in message
...

"Existential wrote in message
...
wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm
curious
about laminating an approx. 4' x 6' area of plywood with some other
thin-ish, or even not so thin-ish material -- from formica
laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for
large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid
Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one side
of
1/4 plywood, where the wood would have a chance to flex. It may work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

I dunno -- I was seeing it as the distance from the neutral axis. You
can't increase the distance from the neutral axis without increasing
volume, so they pretty much go together.

It's not the neutral axis that's determining the force. It's an integrated
value of all of the force exerted by the expanding wood from the bond plane
to the plane of the wood panel farthest from the aluminum. And all of that
force is applied to the bending resistance of the aluminum, through the glue
bond.

Compounding the effect is the greater leverage exerted by any expansion
force generated in the wood fibers farthest from the aluminum.


I was saying that if you only put the aluminum on _one side_, _and_ you
use something thinner than 1/2 inch, that you should be OK.

It would be less likely to sheer off.

Basically, the aluminum is going to move a lot less than the wood. Only
doing one side gives the wood an opportunity to move (and to bow with
humidity), which relieves stress on the glue joint.

But the force is applied *to* the glue joint, as the wood tries to expand.
More wood, more force.


Put Al on both sides of the wood and you're right back to gluing a strong
thing to a weak thing with stuff of questionable strength -- so if you
stress it to breaking, either the glue bond or the underlying wood is
going to shear, or the glue on the compression side is going to let the
aluminum lift and buckle, or the wood on the compression side is going to
let the aluminum dig in and buckle.

True, but as others have said, it will be stiffer to begin with, and much
less vulnerable to expansion from changes in humidity.

But (again) if rigidity is more important than strength, this may not be a
bad way to go.

I think EA has a fairly low-tech application here. He can get away with a
lot, as long as the plywood is thick enough to provide the stiffness he
needs.

'Don't know why he's talking about aluminum, though. That's the biggest
bonding problem, and it has little else to offer to the application. It must
be something he isn't telling us. d8-)

--
Ed Huntress


--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Ed Huntress" wrote in message
...

"Tim Wescott" wrote in message
...
On 07/12/2011 08:14 AM, Ed Huntress wrote:
"Existential wrote in message
...
"Ed wrote in message
...

"Existential wrote in message
...
wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing plywood.

Now, in an interior environment (moisture not an issue), I'm
curious
about laminating an approx. 4' x 6' area of plywood with some
other
thin-ish, or even not so thin-ish material -- from formica
laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for
large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid
Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one
side
of
1/4 plywood, where the wood would have a chance to flex. It may
work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

I dunno -- I was seeing it as the distance from the neutral axis. You
can't increase the distance from the neutral axis without increasing
volume, so they pretty much go together.

It's not the neutral axis that's determining the force. It's an integrated
value of all of the force exerted by the expanding wood from the bond
plane to the plane of the wood panel farthest from the aluminum. And all
of that force is applied to the bending resistance of the aluminum,
through the glue bond.

Compounding the effect is the greater leverage exerted by any expansion
force generated in the wood fibers farthest from the aluminum.


I was saying that if you only put the aluminum on _one side_, _and_ you
use something thinner than 1/2 inch, that you should be OK.

It would be less likely to sheer off.

Basically, the aluminum is going to move a lot less than the wood. Only
doing one side gives the wood an opportunity to move (and to bow with
humidity), which relieves stress on the glue joint.

But the force is applied *to* the glue joint, as the wood tries to expand.
More wood, more force.


Put Al on both sides of the wood and you're right back to gluing a strong
thing to a weak thing with stuff of questionable strength -- so if you
stress it to breaking, either the glue bond or the underlying wood is
going to shear, or the glue on the compression side is going to let the
aluminum lift and buckle, or the wood on the compression side is going to
let the aluminum dig in and buckle.

True, but as others have said, it will be stiffer to begin with, and much
less vulnerable to expansion from changes in humidity.

But (again) if rigidity is more important than strength, this may not be
a bad way to go.

I think EA has a fairly low-tech application here. He can get away with a
lot, as long as the plywood is thick enough to provide the stiffness he
needs.

'Don't know why he's talking about aluminum, though. That's the biggest
bonding problem, and it has little else to offer to the application. It
must be something he isn't telling us. d8-)

Uhhh..... it's SHINY????
Well, at least it starts off shiny!!
And it's half the price of same-thickness SS.

Not absolutely wedded to any single strategy, as there are no doubt lotsa
unforeseen things that will make one strategy more do-able than another.
And regardless of what the laminating strategy is, I have the luxury of
using no adhesive at all, due to the way the edges are treated.

Lotsa options here, super info, appreciate all the input.
--
EA




--
Ed Huntress


--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Existential Angst" wrote in message
...
"Ed Huntress" wrote in message
...

"Tim Wescott" wrote in message
...
On 07/12/2011 08:14 AM, Ed Huntress wrote:
"Existential wrote in message
...
"Ed wrote in message
...

"Existential wrote in message
...
wrote in message
...
On Tue, 12 Jul 2011 07:13:44 -0400, dadiOH wrote:

Existential Angst wrote:
Awl --

Previously (on RW), I asked about coatings, waterproofing
plywood.

Now, in an interior environment (moisture not an issue), I'm
curious
about laminating an approx. 4' x 6' area of plywood with some
other
thin-ish, or even not so thin-ish material -- from formica
laminates,
to .030 SS or Alum sheet, to 1/4" rubberized tile, linoleum.

I recall carpenters using gobs of white elmers glue for
large-contact
wood areas, in building mezzanines in lofts, etc. Then there is
elmer's
carpenter's/wood glue, mastics for tile (what's a mastic,
inyway??),
epoxies, a zillion other adhesives.

Mastic is a pasty material. Like linoleum paste...Liquid
Nails...etc.
__________________

The general Q is: when to use what for what?

http://www.thistothat.com/

For most of the things you mentioned, contact cement.
_________________

Contact cement would, I think, work well for 030 aluminum to one
side
of
1/4 plywood, where the wood would have a chance to flex. It may
work
on
1/2" plywood if the bond isn't heavily stressed.

You're saying the bond would be less stressed with thinner ply than
thicker??
That seems counter-intuitive!

Tim is right.

Because there's less distance to the neutral axis?

No, because the force is a product of the volume of the material that's
trying to stretch or shrink, and thicker material exerts more force.

I dunno -- I was seeing it as the distance from the neutral axis. You
can't increase the distance from the neutral axis without increasing
volume, so they pretty much go together.

It's not the neutral axis that's determining the force. It's an
integrated value of all of the force exerted by the expanding wood from
the bond plane to the plane of the wood panel farthest from the aluminum.
And all of that force is applied to the bending resistance of the
aluminum, through the glue bond.

Compounding the effect is the greater leverage exerted by any expansion
force generated in the wood fibers farthest from the aluminum.


I was saying that if you only put the aluminum on _one side_, _and_ you
use something thinner than 1/2 inch, that you should be OK.

It would be less likely to sheer off.

Basically, the aluminum is going to move a lot less than the wood. Only
doing one side gives the wood an opportunity to move (and to bow with
humidity), which relieves stress on the glue joint.

But the force is applied *to* the glue joint, as the wood tries to
expand. More wood, more force.


Put Al on both sides of the wood and you're right back to gluing a
strong thing to a weak thing with stuff of questionable strength -- so
if you stress it to breaking, either the glue bond or the underlying
wood is going to shear, or the glue on the compression side is going to
let the aluminum lift and buckle, or the wood on the compression side is
going to let the aluminum dig in and buckle.

True, but as others have said, it will be stiffer to begin with, and much
less vulnerable to expansion from changes in humidity.

But (again) if rigidity is more important than strength, this may not be
a bad way to go.

I think EA has a fairly low-tech application here. He can get away with a
lot, as long as the plywood is thick enough to provide the stiffness he
needs.

'Don't know why he's talking about aluminum, though. That's the biggest
bonding problem, and it has little else to offer to the application. It
must be something he isn't telling us. d8-)

Uhhh..... it's SHINY????

Damn. I didn't think about that. d8-)

Well, at least it starts off shiny!!
And it's half the price of same-thickness SS.

Not absolutely wedded to any single strategy, as there are no doubt lotsa
unforeseen things that will make one strategy more do-able than another.
And regardless of what the laminating strategy is, I have the luxury of
using no adhesive at all, due to the way the edges are treated.

Lotsa options here, super info, appreciate all the input.
--
EA

Sometimes it's good to just fish around like that, to hear some options you
might not have considered. But now you can get down to looking at your
objectives in light of what's available.

I still think that laminating it yourself is going to be a losing
proposition relative to buying overlaid ply, but you can check out those
options for yourself.

Let us know how it works out.

--
Ed Huntress

On Jul 12, 1:41*pm, Tim Wescott wrote:
On 07/12/2011 10:09 AM, Robatoy wrote:

On Jul 12, 11:12 am, "Existential *wrote:

So how do you resolve the disparate opinion from Tim and Robatoy, ito of
symmetrical lamination?

I can't speak for Tim, but I have laminated elevator panels,
restaurant cabinets, bars, floors, walls, tables, countertops in a
variety of materials, back splashes, suspended ceiling sections,
valences.... I could go on.

Like I said, I was specifically addressing the oddball case of
laminating aluminum to plywood.

Laminating aluminum, clear, brushed, shiny comes in many diffent
sheens, and is already prepped for laminating.
Just about anybody sells that stuff, Wilsonart, Formica, Arborite,
Nevamar.

It makes a really interesting
theoretical problem, and may even be practical for a homebuilt airplane,
if you need the strength and you're a hot-**** adhesive engineer, and
you keep it dry.

But it's not what EA wants.


Yea.... what DOES he want? LOL

On 07/12/2011 12:08 PM, Robatoy wrote:
On Jul 12, 1:41 pm, Tim wrote:
On 07/12/2011 10:09 AM, Robatoy wrote:

On Jul 12, 11:12 am, "Existential wrote:

So how do you resolve the disparate opinion from Tim and Robatoy, ito of
symmetrical lamination?

I can't speak for Tim, but I have laminated elevator panels,
restaurant cabinets, bars, floors, walls, tables, countertops in a
variety of materials, back splashes, suspended ceiling sections,
valences.... I could go on.

Like I said, I was specifically addressing the oddball case of
laminating aluminum to plywood.

Laminating aluminum, clear, brushed, shiny comes in many diffent
sheens, and is already prepped for laminating.
Just about anybody sells that stuff, Wilsonart, Formica, Arborite,
Nevamar.

But is it load bearing? Can you laminate it onto plywood, then actually
use the strength of the aluminum?

Or is it just a way to make it shiny?

It makes a really interesting
theoretical problem, and may even be practical for a homebuilt airplane,
if you need the strength and you're a hot-**** adhesive engineer, and
you keep it dry.

But it's not what EA wants.


Yea.... what DOES he want? LOL



--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html