Thread: Broke clean at 160 pounds $2 epoxy

Interesting Tim. I like practical tests and measurements. I think there are a few variables to be controlled though, if your comparison of epoxy and PVA is to be useful. I am interested in how this kind of test is related to the construction or fabrication of your table legs. Are you end butting sizeable cross-sections end grain to end grain? Also, I wonder if the stressor weight should be reckoned in leverage terms rather than dead weight. A smaller weight at a longer distance could produce the same tear apart stress. Looking forward to hearing about the PVA.

I just did the PVA clamped it broke at 250 pounds plus, it took all my 110kg body weight then I had to put my hands under the table and pull upwards to get it to break 114kg. I was amazed, this glue when clamped is STRONG. It is selleys crosslinked PVA external glue.

Its a pretty rudimentary test but it still gives me a good comparison i can use, I wanted to get a rough idea of the actual strengths and it was easy to do, the non clamped PVA broke at 95 pounds, which was not too bad considering.

My table 125mm rails are housed into the 100mm square legs 15mm but no mortise and tenon joints, thats why i tested the glue, I have more than twice the surface area for the glue than in test for each joint.
Regards Tim

It would be interesting to see how some real epoxy stands up in the test. That Chickenfeed gear is pure junk, you might as well try spit & sticky tape!

A very interesting test my friend.

Keep it up, put the results in a table ( and write a scientific treatise while you are at it ) and post.

Chickenfeed gear is pure junk

Do you mean there epoxy is junk??
Regards Tim

yes & yes. lol

By nature, isn't epoxy a brittle type of compound?

Like glass is strong but brittle; when it does break the molecular bonds are brittle and break apart very easily

The PVA wouldn't be as brittle and would give a lot more flex before snapping.

I find when I try tests like this, all I learn is how well stuff glues your fingers together.

Thanks for that, I have some good epiglass 2000 epoxy here also, it is like glass when it sets although it is great for fine cracks gets right into the joint and holds it together.
Regards Tim

The only time you would use epoxy rather than PVA is when you need a long setup time that exceeds the grab time of the PVA, or when the cured glue will be wet for an extended period. Cross-linked PVAs such as Kleiberit 303 and Titebond 3 will always be adequate for general woodworking, and are waterproof enough to survive the occasional immersion (I have a chopping board glued with Titebond 3 that is washed daily and the glueline shows no signs of failing after 4 years). In all the testing I've done with cross-linked PVAs, the wood has never split at the glue line.
Cleanup is a problem with cross-linked PVAs, and you have to be especially careful when clamping to make sure they don't come in contact with steel clamps. Kleiberit 303 stains blackwood, so finishing prior to glue-up is recommended.
Epoxy comes with a warnings a mile long, so from an OHAS point of view, it should only be used when PVA is just not an option.

Greg, Titebond 3 is a polyurethane glue - I think you mean Titebond I or II. Otherwise, I agree with your post.

Nope tittybond3 is a pva!

I think we both stand corrected.

Originally Posted by Greg Hawthorne

Epoxy comes with a warnings a mile long, so from an OHAS point of view, it should only be used when PVA is just not an option.

Yeah, I can remember my old man used Araldite to fix anything and everything.
I reckon he used to break stuff just so he had an excuse to mix part a with part b.

Nowadays, you wouldn't want to get the original Araldite mixture on your paws or you'd end up with mushrooms growing from your fingers - all 9 of em