ARTICLE: The Truth About Polyurethane Glue
 

http://www.popularwoodworking.com/fe...ea.asp?id=1064 Some
interesting info.

JOAT

We've got a lot of experience of not having any experience.
- Nanny Ogg

ARTICLE: The Truth About Polyurethane Glue
 

In article ,
(J T) wrote:

Some
interesting info.

Thanks Jay-oh-ay-tee; I did find it interesting as it confirmed what
I've suspected through my own uses.

Curious that Gorilla Glue hasn't done scientific testing on what the
founder claims is the glue's strength strength:

Some polyurethane glues advertise themselves as "super strong" and "the
toughest glue on planet Earth." Other polyurethane glues don't make any
claims about glue strength on the bottle. What gives? Frankly, glue
manufacturers seem divided on this issue.

Dale Zimmerman, a technical specialist with Franklin International, which
manufactures Titebond Polyurethane Glue, says that his company's tests don't
show that polyurethane glue is any stronger than yellow glue. Here's how they
tested the adhesives: They glued together 1"-square blocks of hard maple
using a long grain-to-long grain joint -- the strongest type of glue joint
for wood. Then they attempted to break the blocks apart by testing the
joint's shear strength, which basically means they tried to break the bond by
pushing one block up while pushing the other block down.

And what did they find? Zimmerman says that the joints made by the
polyurethane glue failed around 3,510 pounds per square inch (psi) of
pressure. Franklin's Titebond, a popular yellow glue, failed at 3,600 psi.
And Titebond II, their exterior-grade outdoor glue, failed at 3,750 psi.

"Polyurethane glues stick well and hold odd materials, but they generally
aren't stronger than yellow glues," Zimmerman says. "Yellow glue makes a bond
that is stronger than the wood. So while the polyurethane glue might actually
be stronger, it doesn't matter because the wood will always fail first. It's
not a stronger joint."

Other glue manufacturers disagree. Mark Singer, the founder of Gorilla Glue,
says that polyurethane glue is actually stronger than yellow glue when you
use it in types of joints other than the one that Franklin International
tested. Franklin, he says, used a long grain-to-long grain joint, and that's
a joint where traditional yellow glues already excel. Singer says that the
real strength of polyurethane glues is in an end grain-to-end grain joint or
an end grain-to-long grain joint, which are two joints where yellow glues
have always been lacking.

"Shear strength is not polyurethane glue's strongest feature," he says. "In
end grain-to-end grain the stuff is incredible. It far outperforms (yellow
glues) in end grain. If you coat both surfaces with polyurethane glue, I've
seen it (the glue) migrate 2" into wood."

Singer says his company hasn't actually tested this joint scientifically, but
he says he's seen tests from Europe and in the United States that confirm
this statement.


--
Owen Lowe and his Fly-by-Night Copper Company

ARTICLE: The Truth About Polyurethane Glue
 

Thanks for posting the link. I read it all.

Bob

ARTICLE: The Truth About Polyurethane Glue
 

I find poly (gorilla glue) excels at gluing oily woods. it works great for this.
there other better glues for job but they are not practical or readily
available.

--
Knight-Toolworks & Custom Planes
Custom made wooden planes at reasonable prices
See http://www.knight-toolworks.com For prices and ordering instructions.

ARTICLE: The Truth About Polyurethane Glue
 

"J T" wrote in message
...
http://www.popularwoodworking.com/fe...ea.asp?id=1064 Some
interesting info.

JOAT


FWIW and if you haven't heard. This month's issue September 2004 Issue 157
Wood mag(from the Better Homes and Gardens folks) there is a good study of
various glues and polyurethane too. The author was somewhat scientific in
his experimentation but his measuring devices looked kludged. He
mentions,briefly, his experience with hot hide glue using hide crystals. My
experience, although limited, doesn't agree with his assessment of the hot
hide glue. He said it smells bad and has far less bonding strength than
today's adhesives. For one, the stuff I use has no 'smells foul' odor to
it. Me thinks he got the low end stuff which, indeed, smells ripe when
heated. While SWMBO is looking over the produce at the food store you might
amble on over to the magazine rack and take a look.
Larry

ARTICLE: The Truth About Polyurethane Glue
 

Hide glue is certainly produced from some malodorous ingredients. Modern
types may be a bit less animal collagen and a bit more something else.

Here Dobbin ....

"Lawrence L'Hote" wrote in message
news:9gBKc.125903$XM6.9856@attbi_s53...


FWIW and if you haven't heard. This month's issue September 2004 Issue
157
Wood mag(from the Better Homes and Gardens folks) there is a good study of
various glues and polyurethane too. The author was somewhat scientific in
his experimentation but his measuring devices looked kludged. He
mentions,briefly, his experience with hot hide glue using hide crystals.
My
experience, although limited, doesn't agree with his assessment of the hot
hide glue. He said it smells bad and has far less bonding strength than
today's adhesives. For one, the stuff I use has no 'smells foul' odor to
it. Me thinks he got the low end stuff which, indeed, smells ripe when
heated. While SWMBO is looking over the produce at the food store you
might
amble on over to the magazine rack and take a look.
Larry