Thread: Polyurethane Adhesives..which one?

Thanks for sharing!

I use both Selleys products. Durabond is strong but messy. I prefer working with PVA.

Yeah, I use durabond also, if I remember right, mostly because it has a slightly lower absolute minimum working temp (7deg C) which is important in winter where I live.

The current issue of Fine Woodworking (the one on the newstands at present I mean), there is an article testing various adhesives, including PVA, cross-linked PVA and polyurethane.

In summary the cross-linked PVA worked better in most cases, which was a surprise to the testers (and to me I might add!)

My adhesive of choice is Triton, I have yet to experience a failure.

Ran out a little while ago and when I went to Bunnies so had they. Bought some standard Aquadhere, yuk, thin as. Back to Triton

Their conclusions with regard to polyurethane adhesives were, to say the least, incorrect. What is more the results were in fact quite predictable, due to the design of the test samples.

As no Clamping Pressure was applied to the ACTUAL bond area. They were in fact evaluating the performance of these adhesives as a "Thick film" or "gap filler". Rather than evaluating the true bonding capability of the adhesives.

Clearly a foaming adhesive such as polyurethane,will expand and form a low strength foam if not suitably clamped. The greater the gap the lower the strength of the foam matrix.

The two PVA adhesives and the Epoxy adhesives showed very similar results as the have relatively stable characteristics as a thick film and exceeded the strength of the timber samples.

Whilst having some significance for joints where no clamping pressure can be applied. The results do not indicate the true potential of the adhesives when correctly clamped in edge bonding or lap joints.

Paddy

Thanks for the info Paddy. Just been shopping for some polyurethane glue which I haven't used before. The only stuff I can find way out here is the Durabond but they want $28 for the 450ml bottle which I'd never use up. Thought I'd google for a smaller bottle and found this thread - if I can't find smaller, at least I know it works OK

Sellys PVA exterior is the best for me.

Has anyone used the Bostik MDF Glue? I've been using it as a replacement for PVA primarily because I like the workability, but I've never really tested it for strength. Does anyone have any comment?

I've used the Durabond also, it works really well but is far too messy for most applications.

A local cedar window manufacturer in Margate Tasmania put me onto a glue product which I had never seen before. It is made AVS Adhesives, AV515. It comes in a 300ml silicon type tube, and its performance is outstanding. It has a D4 classification, and is highly water resistant. The tube makes for a mess free glue up and most of all it reacts in 60mins, but again more importantly is the way the excess can be cleaned up without any mess, and it doesn't stain timber, unless PVA on dark timber such as blackwood. It is around $15 per tube, and I would never go back. If you do a search for AV515 on this forum you will find more about it. Cheers