Teardrops n Tiny Travel Trailers

This is a very interesting and seemingly unbiased test on multiple types of glues in wood-wood applications. Tests performed by Case Western Reserve University. I think you will all be very surprised at the "loser" in the tests.

http://www.oldbrownglue.com/pdf/HowStrongisYourGlue_FWW.pdf

dave

No surprise here. :-) I've seen lots of polyurethane glue failures.

I know these guys are materials engineers and I am not, but I do know there are at least a few more types of strength tests other than this one.
- Racking -- which is what I would call this one. Similar to stress on a chair's seat to back legs or sideways pressure to a dresser
- Shear -- force parallel to the glue joint. This is the ASTM D905 test
- Tension -- pulling force, example would be on a drawer front
- Peel -- adhesion of a thin adherand to a thicker one such as a veneer on a substrate
- Cleavage -- force applied to spread the joint apart with a wedging action.

Things are also complicated due to the anisotropic nature of wood, the type of joint, etc.

Yeah, urethane glues are a perfect example of marketing over-ruling fact. One of the big touts is that it has good gap-filling characteristics. Unfortunately, when it fills a gap of any significant size, its strength goes down the crapper. Its strength is just OK at best, and the ability to take stain well is good. Its open time is especially attractive. It has its places, but don't be fooled about the gap-filling trait. From a cabinetmakers perspective, good old yellow glue is your best bet all-around.

Best,
Tom

For more glue tests, check out Matthias Wandel on youtube. https://www.youtube.com/user/Matthiaswa ... query=glue

He's done a lot of interesting tests. One video I haven't been able to find was a test of clamping pressure for different types of glue. If I remember correctly, polyurethane worked best when clamped lightly, while yellow glue worked best when clamped tight.

https://woodgears.ca/joint_strength/glue.html Here's his webpage on the subject.

Awesome test! Now I'm glad I built my floor with titebond3