By David J. Marks
Throughout history veneering was considered an art form and was generally only commissioned by the very wealthy.
The art of working with veneers dates back 4,000 years to the ancient Egyptians. In earlier times, veneer quality logs were sawn by hand by two craftsmen using a large frame saw. The advantages of working with veneers are stability, economical use of wood, and access to some of the rarest woods in the world, just to name a few.
There are many things to consider when veneering. The following are some of the essential points:
1) Edge joining 2) Types of glue 3) Substrates 4) Clamping systems
For edge joining straight pieces you can clamp a straight edge to the stock as a guide and use a sharp knife or a veneer saw, which has a curved edge, to make the cuts. My preference is to sandwich the veneers between two pieces of ½” to ¾” MDF (Medium Density Fiberbrand) and cut them with a router. Use the top piece of MDF as a guide. You will need to make sure the MDF is straight by making a clean cut on your Table saw or passing it over the jointer. Next, select a router bit that is designed for flush trimming and has a bearing at the top. Place 2 or more sheets on to the underside of your MDF guide and hold them in place with some tape. Keep in mind that veneers can be somewhat fragile until they are glued to a substrate, so it’s a good idea to use some of the medium strength adhesive masking tapes such as the blue or green colored tapes. Also, position your stack of veneers so that the edges you want trimmed are sticking out about 1/8” or more from your MDF straight edge. Now add your 2nd sheet of MDF to the bottom of the stack aligning it with the edge of the veneers so that they are supported.
The next step is to hold the stack together with clamps and then with the bearing up against the straight edge, rout the veneers. You will need to place clamps every 8” or so to ensure a good edge so plan on making partial cuts and then repositioning the clamps. Veneer tape is used to hold the edges together. This tape is paper with a dry adhesive. The adhesive is activated by wetting it with a sponge, causing it to become sticky. Generally, I’ll apply a little yellow glue to the edges of the veneers, pull them tight with blue masking tape and when dry, remove the blue tape and apply the veneer tape. Once you have created your full sheet, it will need to be glued up. I do not recommend using contact cement as an adhesive because it remains flexible. Yellow Aliphatic resin glue works, but I believe the best results are obtained with slow setting Urea resin glue. My favorite is Unibond. Good results can also be obtained with Weldwood plastic resin glue.
Veneer can be applied to any substrate considered to be stable; typically that means plywood or MDF. While MDF was designed for use with veneering with its void free smooth surface, I would say it works great for most applications except a situation such as an unsupported tabletop. Where strength is needed, a good quality plywood like apple ply (alder core with maple faces) should be used. One of the fundamental rules of veneering is that veneer must be applied to both sides of the substrate to maintain equilibrium.