Do you have a recommended finishing method for marquetry pictures, given that they typically incorporate a variety of wood types, wood grains, grain directions, etc.? Would you have any pro or con comments about the idea of finishing a marquetry picture with several coats (eight to ten) of Zinsser SealCoat™ Sanding Sealer, sanding between every two or three coats? I find that this product goes on rather easily and, since a marquetry picture doesn’t experience any appreciable wear, I thought it would be an acceptable alternative to the much “smellier” Deft® lacquer that I’ve been using for a number of years now.
— Robert Swanson
You chose wisely. Zinsser SealCoat Universal Sanding Sealer is pure, dewaxed shellac, and that is an excellent finish for a marquetry picture. Dewaxed shellac seals well over all woods, comes in a variety of hues, and has good wetting and clarity. I like to flood on the first coat liberally, then wipe it all off. Woods prone to absorb more finish will do so, resulting in very uniform sealing. Thus, by the time you get to the second coat, you have a more uniform surface than you started with.
Because it contains a polar solvent, the first coat of shellac will raise the grain of wood slightly, leaving it not rough, but furry. I like to knock back the “fur” with a very light scuff using 800-grit sandpaper, taking pains to avoid cutting through to raw wood. Because shellac dissolves itself with each coat, you don’t need to sand after that unless you get dust, dirt, brush marks or spray marks (runs, overspray, etc.) in the finish. As long as it goes on smoothly, there’s no need to sand between coats when using shellac.