can be used in veneer work but its expensive, requires mixing,
and has a short life once it is mixed. Epoxy is best used for
substrates where ordinary veneer glue will not adhere (plastics,
good news is that it's a highly effective grain filler for veneer
that you are not going to stain or dye. The key
is to use a plastic spreader and use just a little more hardener
than you normally would. When it's dry, hand sand the panel with 150 grit paper and finish with your favorite top coat.
Polyurethane Glue bonds to anything. It is suitable for veneering when the veneer has to be pressed to a non-porous surface such as plastic. I would suggest using this glue only on small panels because it is difficult to spread, and it bleeds-through more than most adhesives due to the foaming action. It's also quite expensive.
Yellow glue (PVA) is probably the first glue that comes to mind when you say "glue" to a woodworker. Despite the recommendations of many woodworkers, I have never found yellow glue to be suitable for veneering. This type of glue never fully hardens, and thus allows the veneer to "creep" or move during seasonal changes in humidity. And because of its thin consistency, yellow glue also has a tendency to bleed through and discolor the veneer. Lastly, since yellow glue dries with a soft glue line, it is also very difficult to sand.
Hide Glue is the most traditional veneering adhesive. Its use dates back over 4,000 years ago to Egyptians who used it on furniture for the pharaohs. The method is called hammer veneering which derives its name from the use of a tool called a veneer hammer. The hammer is used to press the veneer sheets onto the substrate.
The method also requires a means of heating the glue typically in a "double boiler." Hide glue is very durable and it can be re-heated and reactivated if bubbling occurs. Hide glue can not be used in a vacuum press unless the appropriate salt or urea is added. For those interested in hammer veneering without the use of hide glue, check out the FSV adhesive below.
FSV or Flex-Pro is a good adhesive for paper-backed veneers when a vacuum press and a cold press veneer glue can not be used. This type of adhesive is not suitable for unbacked wood veneer.
It is applied in a manner similar to contact cement and has a very high initial tack but it dries harder and doesn't allow delamination when cured. Generally speaking, it should be used on porous substrates but I've had success using this glue to veneer over painted window and door jambs as well as stair stringers. It is also an excellent adhesive for those who prefer the traditional hammer veneering method.
Contact Cement is available in two versions. One is solvent-based and is highly flammable. It emits dangerous fumes that can linger in the shop for days.
Thanks to advances in chemical technology, there are now water-based contact cements which are non-toxic and work as well or better than the solvent-based type. For several years, water-based contact adhesives were considered inferior to the solvent-based cements (and they were inferior) but this has changed dramatically with the introduction of water-based cements such as Titan DX™.
Keep in mind that contact cements are only suitable for use with paper/wood backed veneers. There has been a lot of debate over this and it's one of the most common emails I receive. Check out this link.