Good Morning-

I googled "Laminating plywood beams" but didn't come up with any
responses over the standard 1" or 2 sheets of 3/4 for benchtops.

I would like to create a laminate post 4" or 5" square using plywood.
I'd most likely leave the edges rough, but for a better 'look' I could
extend the last two pieces at a 45 degree angle bevel cut and slip a
another piece on the outside edge.

I'm doing this to increase the structural strength of a (theoretical
now, thanks craigslist) winepress. I intend to test the beam under
compression to see if it will fail and at what force.

Would it be better to glue up multiple pieces first, then glue them all
together (trimming / handplaning along the way) or glue them all up in
once massive stack? I'd like to try to minimize warping during the
process.

Any insight would be greatly appreciated-

Jason

(and for those that said to buy a wine press- ask and Craigslist shall
deliver: I found an 18" wine press and crusher for 200$. I figure
it'll take about 150$ to clean up and fix and replace the rusted iron
with SS, but it's worth it.)

wrote:
Good Morning-

I googled "Laminating plywood beams" but didn't come up with any
responses over the standard 1" or 2 sheets of 3/4 for benchtops.

I would like to create a laminate post 4" or 5" square using plywood.
I'd most likely leave the edges rough, but for a better 'look' I could
extend the last two pieces at a 45 degree angle bevel cut and slip a
another piece on the outside edge.

I'm doing this to increase the structural strength of a (theoretical
now, thanks craigslist) winepress. I intend to test the beam under
compression to see if it will fail and at what force.

Would it be better to glue up multiple pieces first, then glue them all
together (trimming / handplaning along the way) or glue them all up in
once massive stack? I'd like to try to minimize warping during the
process.

Any insight would be greatly appreciated-

Jason

(and for those that said to buy a wine press- ask and Craigslist shall
deliver: I found an 18" wine press and crusher for 200$. I figure
it'll take about 150$ to clean up and fix and replace the rusted iron
with SS, but it's worth it.)


I assume you're not looking for anything longer than 3'. Why not check
a construction site or stop by a lumber yard and look for a cutoff of a
laminated beam.

I would think that around 4x4"x3' a homemade plywood beam would be
weaker than solid wood. Why not just try a pressure treated 4x4 and
see if it will take the pressure. If you could find one straight
enough you could wrap it with plywood or hardwood to pretty it up and
add some srtength.

Since you are going to be putting stress on whatever you use I would
skip trying to miter the edges. They are bound to open up the first
time put the squeeze on. Stick with simple butt joints if you wrap it.

Georgia Pacific has a ton of detailed specifications on their site
engineered lumber if you want to do some theoretical calculations
first. This calculator may help you if you want to try solid lumber.

http://www.awc.org/calculators/span/...eversecalc.asp

Uh...it's been done and all worked out by
them there engineering types.

http://www.aitc-glulam.org/

You can buy them or go by a construction site and
they might give you what you are looking for. You
may have to look a little but depending on your
area, there is always a site using many glulams.




wrote:


I would like to create a laminate post 4" or 5" square using plywood.
I'd most likely leave the edges rough, but for a better 'look' I could
extend the last two pieces at a 45 degree angle bevel cut and slip a
another piece on the outside edge.

Thu, Sep 21, 2006, 8:18am (EDT-3) (RayV) doth
sayeth:
snip Why not just try a pressure treated 4x4 and see if it will take
the pressure. snip

I hope you're not recommending using pressure treated wood as part
of a wind press.



JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

I'm trying to avoid PT anywhere in the press, except for perhaps the
support legs- everywhere else I'd fear something would flake in.

I was looking for 4' beams because I could then attach them to 4' wide
by 6" or 8" solid core wood. I was under the impression, from my
materials courses, that laminates were far stronger than the base
material.

Like I said I'm concerned now about figuring out how to test the
strength of the construction- I've got a press on the way and
(assuming) I can file/brush all the bad spots down I'll be using it
straight away...

Others have constructed 8 ton presses that have withstood the force- I
don't think they'd fail catastrophic- just with a loud 'crack' or
something.

Jason
J T wrote:
Thu, Sep 21, 2006, 8:18am (EDT-3) (RayV) doth
sayeth:
snip Why not just try a pressure treated 4x4 and see if it will take
the pressure. snip

I hope you're not recommending using pressure treated wood as part
of a wind press.



JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

I'm trying to avoid PT anywhere in the press, except for perhaps the
support legs- everywhere else I'd fear something would flake in.

I was looking for 4' beams because I could then attach them to 4' wide
by 6" or 8" solid core wood. I was under the impression, from my
materials courses, that laminates were far stronger than the base
material.

Like I said I'm concerned now about figuring out how to test the
strength of the construction- I've got a press on the way and
(assuming) I can file/brush all the bad spots down I'll be using it
straight away...

Others have constructed 8 ton presses that have withstood the force- I
don't think they'd fail catastrophic- just with a loud 'crack' or
something.

Jason
J T wrote:
Thu, Sep 21, 2006, 8:18am (EDT-3) (RayV) doth
sayeth:
snip Why not just try a pressure treated 4x4 and see if it will take
the pressure. snip

I hope you're not recommending using pressure treated wood as part
of a wind press.



JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

Subject

What are you trying to laminate.

Using nothing but 1/2", 4 ply, CDX, and epoxy, can laminate a
structure you simply won't be able to destroy with out a tank and some
105 shells.

Lew

Thu, Sep 21, 2006, 4:56pm (EDT-3) doth sayeth:
I'm trying to avoid PT anywhere in the press, except for perhaps the
support legs- everywhere else I'd fear something would flake in. snip

Trying? Except for the legs? Your project, your money, put any
type of wood you want in it.

Just wonder what would happen if a dog or cat, or little kid,
licked some spilled juice of a PT leg.

Note to self:
Do not, repeat not, accept any type of wine from this guy. Ever.



JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

In article .net,
Lew Hodgett wrote:
Subject

What are you trying to laminate.

Using nothing but 1/2", 4 ply, CDX, and epoxy, can laminate a
structure you simply won't be able to destroy with out a tank and some
105 shells.

Lew

Or maybe a few ounces of kerosene and a match.


--
Every complicated problem has a simple solution that doesn't work.

Larry Wasserman Baltimore, Maryland
lwasserm(@)charm(.)net

wrote:
I'm trying to avoid PT anywhere in the press, except for perhaps the
support legs- everywhere else I'd fear something would flake in.

I was looking for 4' beams because I could then attach them to 4' wide
by 6" or 8" solid core wood. I was under the impression, from my
materials courses, that laminates were far stronger than the base
material.

Like I said I'm concerned now about figuring out how to test the
strength of the construction- I've got a press on the way and
(assuming) I can file/brush all the bad spots down I'll be using it
straight away...

Others have constructed 8 ton presses that have withstood the force- I
don't think they'd fail catastrophic- just with a loud 'crack' or
something.

Jason

I mentioned 'trying' a PT 4x4 because they are easy to come by and
reasonably cheap for a test. I have about 5 of them laying behind my
shed if you need one.

Oops, that one got away from me befor I finished typing.

Making your own glue-lams allows you to cut out the defects
so that all the lamiantions are all perfect wood. If you buy a
commercial laminated product it is likely (all but certain) that
the internal layers will contain defects and voids. That is
allowed by the standards orgs for most grades of plywood.

Even then marine grade or aircraft birch plywood, which are
supposed be free of internal voids, are cross laminated and
for most beams or columns that is weaker than wood with
a uniform grain direction. The advantages to cross-lamination
are dimensional stablity and resistance to splitting, not
basic strength.

You can get a better strength to weight ratio by using composite
beams, built-up sections like I-beams or box beams. Probably
that was the source of your confusion. Those aren't stronger than
solid wood of the same overall dimensions, they're lighter.

I'm not clear on the geometry of how you are using this particular
member but you would almost certainly get a stonger piece by
gluing 1x or 2x lumber instead of plywood. Three 2x4s glued
together in the shape of an I-beam would be much stronger than
the same three glued side by side. Unlike the example above,
that would keep the wieght the same but increase the strength
by changing the overall dimensions.

Like Joat, I don't see any reason to use any treated lumber
anywhere in the press.

--

FF