Not sure if many are aware of the detailed test carried out by a US woodworking magazine ...
I spend a fair amount of money buying quite expensive Polyurethane glue, and while it is still my first choice for fast setting glue .... esp for mitres & plugs ... I was surprised that Gorilla glue came out the worst in the test for strength.
It may be gap filling and fast setting, but so is jelly.
PVA type 1 came out the best
I have loaded the full report here ..
on test.
And, even then, you can't extrapolate beyond the particular brands/ formulations on test.
because of its strength under ideal conditions, but because it stays strong when wet. PVA can fail when wet.
NT
I think you can. PVA is PVA and doesn't vary greatly between generic 'white' brands and generic 'aliphatic;' or yellow brands.
It also echoes my experience making models..ultimately cheap white PVA has proved better than anything - epoxy, or superglue or foaming poly - for ultimate strength.
With hot glue being a surprisingly GOOD thing - much better than expected.
Epoxy does not actually work that well on wood. It tends to grab te surface layer only, and not penetrate into the wood like a solvent or water based glue does.
it fails not by breaking itself, but by tearing off the wood surface.
If you heat it till its runny and/or apply pressure, its a bit better.
I use it extensively to bond wire undercarriages to ply formers. Covered with a later of glass cloth impregnated with epoxy. usually heated with a heat gun and then covered in a polythene sheet with modelling clay used to apply uniform pressure for a few minutes till its set.
Even so it is in the limit possible to tear the whole thing off the wood without breaking the wood..fibres of the wood come off with it.
That is a bit unfair .. it was far more scientific than any other DIY test I have seen on glues.
didn't do well in the tests .. came out bottom
The irony being that that the one distinction you draw is the most meaningless marketing bullshit. Much more meaningful is whether it is a cross-linking PVA (D3 or D4) or not, not whether it has some yellow dye in it and extra tackifier resins.
But generally, I'm not going to disagree much with you over decent quality PVAs with or without yellow dye.
But polys and epoxies vary very much more as between each other.
From a very low base point, you may well be correct, but that doesn't make my observation wrong. Are you claiming it was worthy of a journal?
waterproofness and only instantaneous high-load failure, not slow fatiguing.
Pity they didn't review a cascamite type glue alongside them.
I was also taught, that polyurethane especially needs a high clamping pressure to produce a high-strength joint. i.e. any of the glue that foams is lousy for strength.
I took the view that for joints with large contact area by poor/irregular finish, PU was likely to do better than PVA which may end up with a small effective contact area.
But I added lots of screws to the joint in question so the joint was well clamped - and the screws take a lot of the load - the glue is really supplimental to add stiffness.
Ugghh.. chewy..
I'd imagine it has negligible fibre content.
I have used Cascamite myself .. found it a damn good glue ... seems to have dropped out of favour. I have horses in filed next door .. maybe I should boil up some hoof glue :-)
I am trying to work out what that means..they are in serried ranks? Or filing cabinets?
.. maybe I should boil up some hoof
An editor might be an investment.
Anyway, do remove the hoof first.
Its a hard call - PU has little strength where the contact is gaped and foamed, and less strength than the PVA on the good points of contact. If you really need a gap filling glue for irregular surfaces you are probably better off with epoxy.
Is there a less expensive source of epoxy by the litre? (less expensive than lots of tubes of araldite)...
It keeps changing its name. Also been marketed as Extramite, and now as Polmite.
All the same stuff. As they sell it by up-to a 25Kg bag, it must still be popular.
See:
It is slightly less convenient, and perhaps more suited to a professional joinery set-up, where all the work will be prepped for a gluing-up session at the end of the day - the cascamite made up in sufficient quantity - and everything cramped up overnight (and having a rack of dozens of g-clamps is the norm).
Another poster was asking about alternatives to tubes of Araldite - West Systems epoxy is, in the UK, almost used to the exclusion of all other epoxies in boatbuilding.
Not cheap to get started with West Systems, but if your usage justifies the initial costs, the rolling costs probably aren't too bad.
well use polyester then - a.k.a. car body filler.
Not from what I've seen. PU foam has great sticking power over a wide area, so for bunging insulation panels onto flat walls it just the job, as they're not under great mechanical stress. The makers also produce a low-expansion foam glue for exactly that, but I've found a thin line from a gun of ordinary yellow foam works well.
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