Glue for Pre-Finished Plywood
The cured surface of pre-finished plywood offers very poor adhesion for just about all glue. September 26, 2009
Does anybody know of a glue that will bond poplar lumber or unfinished birch plywood to pre-finished maple plywood? Would something like ROO glue do this?
From contributor L:
Roo or Franklin's melamine resin glue will work. You just need one face that is absorptive. Curing time is longer than with Titebond yellow glue. A bit of scuff sanding is a good idea.
From contributor E:
I don't know we can give you a good answer. Here in Oregon I went to the local plant that makes the pre-finished plywood I buy. I went there because the finish is bulletproof and I wanted to find out where they get it. The owner said the product they use is a siliconized poly product. The silicon that's in it makes the adhesion of any of the plastic type glues like Titebond or Roo melamine glue unlikely. I have noticed that even after a glue joint sits awhile, a few good hard smacks will separate the joint and all you see is a thin layer of hardened dry glue. My guess is we would have to use something on the order of epoxy to really get a good mechanical joint. You might want to do a little homework and find out what your manufacturer is using and go from there.
From contributor J:
Contributor E is right. The melamine glues don't work worth a hoot on UV cured pre-finished ply. Scuffing helps a little, but in order to get a glue bond worth having, you need to completely remove the finish. I have never tried epoxy though.
From contributor A:
We tried all of the glues. They all fail. Either they don't like to stick to the pre-finished surface or the finish peels right off the plywood. We typically use rabbet/dado construction so gluing is a non-issue. However, we don't even bother anymore with glue when using butt joints... more screws.
From contributor N:
There should be a PUR that would work - we have glued wood to glass.