[Teamcasa]

"alexy" wrote in message
...
I am getting ready to do a bent lamination, and have questions about
adhesives and springback.

I have heard that urea formaldehyde or plastic resin glue is the best
to use for this application because of the long open time and lack of
creep once set. I am having a hard time finding it, though. I can get
a gallon from Highland Woodworking but because of its relatively short
shelf life, I would end up throwing away 95% of it. Anyone know a good
source for small quantities (Atlanta area desired, but online source
okay, too) or whether another type of glue would work as well. My
application is not load-bearing, and in fact will be "captured" by
another structure. I'm laminating 4 pieces of 1/8" thick poplar for
edge banding of the inside of an elliptical arch cut in plywood.

I have a form for bending my lamination, that I made slightly
undersize, anticipating that there will be some "springback" when the
lamination is removed from the form. Anyone have any ideas or formulas
for estimating how much that will be in advance, or is it just a case
of trial and error?
--
Alex --

Alex, For the project you describe above, I would use polyurethane glue.
Its has sufficient open time for your project. I only use plastic resin
glue when I need + 20 minutes to get the project clamped up.

Dave

[alexy]

"Teamcasa" wrote:


"alexy" wrote in message
.. .
I am getting ready to do a bent lamination, and have questions about
adhesives and springback.

I have heard that urea formaldehyde or plastic resin glue is the best
to use for this application because of the long open time and lack of
creep once set. I am having a hard time finding it, though. I can get
a gallon from Highland Woodworking but because of its relatively short
shelf life, I would end up throwing away 95% of it. Anyone know a good
source for small quantities (Atlanta area desired, but online source
okay, too) or whether another type of glue would work as well. My
application is not load-bearing, and in fact will be "captured" by
another structure. I'm laminating 4 pieces of 1/8" thick poplar for
edge banding of the inside of an elliptical arch cut in plywood.

I have a form for bending my lamination, that I made slightly
undersize, anticipating that there will be some "springback" when the
lamination is removed from the form. Anyone have any ideas or formulas
for estimating how much that will be in advance, or is it just a case
of trial and error?
--
Alex --

Alex, For the project you describe above, I would use polyurethane glue.
Its has sufficient open time for your project. I only use plastic resin
glue when I need + 20 minutes to get the project clamped up.

Dave

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's academic
in my relatively low-stress project?
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

[Teamcasa]

snip
Alex, For the project you describe above, I would use polyurethane glue.
Its has sufficient open time for your project. I only use plastic resin
glue when I need + 20 minutes to get the project clamped up.

Dave

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's academic
in my relatively low-stress project?
--
Alex

I use blue tape to stop creep. Its really not much of an issue unless the
bend is severe. Just make sure you wear nitrile (blue) gloves.
Dave

[Lew Hodgett]

alexy wrote:

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's academic
in my relatively low-stress project?

SFWIW, For the price of Gorilla Glue or equal, you can add maybe 10%
and get epoxy.

There is no comparison between epoxy and Gorilla Glue.

Lew

[alexy]

Lew Hodgett wrote:

alexy wrote:

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's academic
in my relatively low-stress project?

SFWIW, For the price of Gorilla Glue or equal, you can add maybe 10%
and get epoxy.

There is no comparison between epoxy and Gorilla Glue.

Thanks, Lew. I wonder what the trade-offs are between UF and epoxy?
Sounds like you are a "fan" of epoxy, but there are always tradeoffs.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

[alexy]

"Teamcasa" wrote:

I use blue tape to stop creep.

Either I am misusing the term "creep", or I don't understand what you
are doing with the blue tape to stop it. I thought that creep in a
glue joint referred to movement in response to sheer forces.

--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

[Teamcasa]

"alexy" wrote in message
...
Lew Hodgett wrote:

alexy wrote:

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's academic
in my relatively low-stress project?

SFWIW, For the price of Gorilla Glue or equal, you can add maybe 10%
and get epoxy.

There is no comparison between epoxy and Gorilla Glue.

Thanks, Lew. I wonder what the trade-offs are between UF and epoxy?
Sounds like you are a "fan" of epoxy, but there are always tradeoffs.

Lew LOVES epoxy (and must have stock WestSystems). He suggests it for
virtually every fix where an adhesive is used. Since he works on boats, its
a natural choice. For the rest of us, we get to use several diffrent glues.

Dave

[Teamcasa]

"alexy" wrote in message
...
"Teamcasa" wrote:

I use blue tape to stop creep.

Either I am misusing the term "creep", or I don't understand what you
are doing with the blue tape to stop it. I thought that creep in a
glue joint referred to movement in response to sheer forces.


You are not. Creep is what happens to the wood sandwich as clamping
pressures are applied. Blue tape will hold it most of the time for flat
stock glue ups, it has a hard time when the form includes a bend and twist.
Unless your bending form incorporates a twist as well as a bend, you should
not have a problem with creep. If you do, and blue tape will not hold, (try
it without glue first) apply clamps and cauls to prevent severe creep. Use
clear packing tape on the cauls to prevent the adhesive from sticking to it.

Dave

[Lew Hodgett]

Teamcasa wrote:


Lew LOVES epoxy (and must have stock WestSystems).

Actually, I don't use any West Systems.

They are not competitive for my applications.

The reason I suggest them is that they offer small quantities, are
readily available almost every place, and they offer very good tech
service.


Lew

[Teamcasa]

"Lew Hodgett" wrote in message
hlink.net...
Teamcasa wrote:


Lew LOVES epoxy (and must have stock WestSystems).

Actually, I don't use any West Systems.

They are not competitive for my applications.

The reason I suggest them is that they offer small quantities, are readily
available almost every place, and they offer very good tech service.


Lew


What do you use?
Dave

[Lew Hodgett]

Teamcasa wrote:

What do you use?

I work with Diversified Materials in San Diego.

They use several different suppliers based on price and availability.

Laminating epoxy is strictly a commodity, IMHO.

Lew

[alexy]

"Teamcasa" wrote:


"alexy" wrote in message
.. .
"Teamcasa" wrote:

I use blue tape to stop creep.

Either I am misusing the term "creep", or I don't understand what you
are doing with the blue tape to stop it. I thought that creep in a
glue joint referred to movement in response to sheer forces.


You are not. Creep is what happens to the wood sandwich as clamping
pressures are applied. Blue tape will hold it most of the time for flat
stock glue ups, it has a hard time when the form includes a bend and twist.
Unless your bending form incorporates a twist as well as a bend, you should
not have a problem with creep. If you do, and blue tape will not hold, (try
it without glue first) apply clamps and cauls to prevent severe creep. Use
clear packing tape on the cauls to prevent the adhesive from sticking to it.

Okay. That's not my understanding of the term. I think it refers to a
property of the cured glue line. From an engineering dictionary:
:Creep
:the dimensional change with time of a material under load.

and from the Franklin Global web site:
:What is creep in an adhesive bond?
:Creep or cold-flow in an adhesive bond is the deformation of
:the bond line under a stress or load over a period of time


--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

[alexy]

"Teamcasa" wrote:


"alexy" wrote in message
.. .
Lew Hodgett wrote:

alexy wrote:

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's academic
in my relatively low-stress project?

SFWIW, For the price of Gorilla Glue or equal, you can add maybe 10%
and get epoxy.

There is no comparison between epoxy and Gorilla Glue.

Thanks, Lew. I wonder what the trade-offs are between UF and epoxy?
Sounds like you are a "fan" of epoxy, but there are always tradeoffs.

Lew LOVES epoxy (and must have stock WestSystems). He suggests it for
virtually every fix where an adhesive is used. Since he works on boats, its
a natural choice. For the rest of us, we get to use several diffrent glues.
And his love of epoxy may be well founded--in its many formulations it
is wonderfully flexible. But I still believe that there are tradeoffs
in selection of any construction material or technique, and I'd like
to see some discussion to form the basis of an informed choice.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

[J. Clarke]

"alexy" wrote in message
...
"Teamcasa" wrote:


"alexy" wrote in message
. ..
Lew Hodgett wrote:

alexy wrote:

I've thought about that, but how is it for creep? My impression is
that UF and epoxy are better in this regard. But maybe that's
academic
in my relatively low-stress project?

SFWIW, For the price of Gorilla Glue or equal, you can add maybe 10%
and get epoxy.

There is no comparison between epoxy and Gorilla Glue.

Thanks, Lew. I wonder what the trade-offs are between UF and epoxy?
Sounds like you are a "fan" of epoxy, but there are always tradeoffs.

Lew LOVES epoxy (and must have stock WestSystems). He suggests it for
virtually every fix where an adhesive is used. Since he works on boats,
its
a natural choice. For the rest of us, we get to use several diffrent
glues.
And his love of epoxy may be well founded--in its many formulations it
is wonderfully flexible. But I still believe that there are tradeoffs
in selection of any construction material or technique, and I'd like
to see some discussion to form the basis of an informed choice.

Cagle, in "Handbook of Adhesive Bonding", a well known engineering
reference, recommends UF or RF over epoxy for wood-to-wood joints exposed to
weather. I don't remember why now and my copy is not readily accessible.
However he was writing over 30 years ago and the available epoxy
formulations may have improved since then.

Personally I generally use Titebond or PU for the convenience, but if it's
mission-critical indoor and I've got a good fit I go for the UF and
mission-critical outdoor the RF.

OTOH, I've got an assembly I'm going to glue up with T88 epoxy tomorrow, the
reason being that it's outdoors, the temperature right now is going down
into the high 30s at night, and T88 will cure at that temperature
(eventually) while UF and RF aren't rated to cure below 70 and the rest not
below 50.

[Teamcasa]

"Teamcasa"
You are not. Creep is what happens to the wood sandwich as clamping
pressures are applied. Blue tape will hold it most of the time for flat
stock glue ups, it has a hard time when the form includes a bend and
twist.
Unless your bending form incorporates a twist as well as a bend, you
should
not have a problem with creep. If you do, and blue tape will not hold,
(try
it without glue first) apply clamps and cauls to prevent severe creep. Use
clear packing tape on the cauls to prevent the adhesive from sticking to
it.

Alex
Okay. That's not my understanding of the term. I think it refers to a
property of the cured glue line. From an engineering dictionary:
:Creep
:the dimensional change with time of a material under load.

and from the Franklin Global web site:
:What is creep in an adhesive bond?
:Creep or cold-flow in an adhesive bond is the deformation of
:the bond line under a stress or load over a period of time

Alex, I don't think that applies to furniture making. Structural materials,
subject to significant pressures and/or vibration and large temperature
fluctuations, maybe. If you are making a glue lamination beam (GLB), that
may have to hold during a fire, then I'd worry about that type of creep.

Dave

[Andrew Barss]

Teamcasa wrote:
: :What is creep in an adhesive bond?
: :Creep or cold-flow in an adhesive bond is the deformation of
: :the bond line under a stress or load over a period of time
:
: Alex, I don't think that applies to furniture making. Structural materials,
: subject to significant pressures and/or vibration and large temperature
: fluctuations, maybe. If you are making a glue lamination beam (GLB), that
: may have to hold during a fire, then I'd worry about that type of creep.


The most common sense of "glue creep" in woodworking is pretty
much Alex's, but perhaps with 'time' replacing 'load'. Concretely,
it's the phenomenon of having two pieces glued together become non-flush
with one another at the glue line. Most common with white and yellow
glues.

- Andy Barss