Darryl Keil
Posts: 1455
Joined: 2003-05-22
Location: Maine
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Over the years I have repeatedly been questioned about which PVA glue should be used when gluing veneer. Anyone who knows me or has read my posts on this subject knows that the hardness of the glue line is my first priority when gluing veneer. Hence my preference for urea formaldehyde resin glues, hands down. With that said there are times when I feel a PVA glue is fine to use, and I understand that many woodworkers who work with veneer prefer to use this glue, even if it doesn’t have the same level of performance as a urea resin glue does.
With this in mind I decided to do some testing on a number of different PVA glues to help those that are using this type of glue get the hardest glue line possible. I chose five PVA glues to do my testing with, Titebond regular, Titebond II, Titebond II Extend, Titebond Extend Original and Titebond Cold Press glue. I chose the Titebond brand for a number of reasons. One, its probably one of the most easily accessible glues for most woodworkers. Two, it’s the brand I get asked most often about. Three, Franklin Chemical Co., has probably more choices than any other manufacturer, at least to smaller shop users, and four, I thought doing the test from within one manufacturer kept it from getting out of control with too many choices. Maybe another time I’ll compare one manufacturer to another. Don’t hold your breath on that one though.
So, with the hardness of the glue line as my most important criteria, I performed the testing like this. On a piece of glossy plastic I poured out about a 12” strip of glue and let it dry for three days on the plastic. After that I could pop it off and continue to let it dry out for another week clamped lightly between a couple of pieces of plywood to keep it from warping too much.
Once all the samples were thoroughly dry I performed my test, which simply meant I took each one and bent it until it broke, or at least tried to. The clear looser was the Cold press glue, quite a surprise since this glue is designed for pressing veneers. I couldn’t get it to break unless I aggressively attempted to fold it completely back on itself. Obviously hardness was not high on the criteria list for this glue. Third and forth places equally were the two Titebond II’s, the regular one and the Titebond II Extend. They would break but with a fair amount of bending. Having a cross linker to make this glue waterproof does nothing for hardness. Second place was good old regular Titebond. It would bend a little but not much before it broke, much better that the Titebond II’s. The clear winner was Titebond Extend Original. You could hardly bend it at all before it snapped. Not only was this the hardest of the lot but also claims a longer open work time which is another quality you want in a veneering glue. I say “claims” because I didn’t see this had any more open work time than regular Titebond. Clearly Titebond II was the worst offender in tack time with Cold Press glue the best in this category by a fair margin, although compared to urea resin glues it was still a short open work time. Unfortunately I would never use Cold Press glue for veneering because it was the softest glue line of the group, by quite a lot, and hardness is my most important criteria for a veneering glue.
So, if for whatever reason you’re not going to use a urea resin glue, which by the way, wont bend in the slightest and shatters into pieces when performing this test, I would use Titebond Extend Original. Maybe another time I'll try other brands and see how they stand up to the Extend.
There you have it, for whatever its worth. There’s a lot more I could say on the subject, like gap filling ability, temperature resistance, bleed through, sandability, etc. but that’s about it for now.
Darryl Keil
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