Oil & Wiping-Varnish Finishes
Ever since I began woodworking in the 1970s, there has been confusion about “oil” finishes. The confusion exists because some manufacturers label their wiping-varnish finishes “oil.” The confusion is then compounded when articles in woodworking magazines repeat the manufacturer’s labeling even though in many cases the labeling doesn’t make sense. The products labeled oil just don’t act like oil.
In fact, oil and wiping-varnish finishes, no matter how they are labeled, could hardly be more different. Linseed oil and tung oil, the two drying oils commonly available to us, never get hard so they can’t be built up. All the excess has to be wiped off after each coat or the surface remains gummy and sticky.
In contrast, wiping-varnish finishes are varnish (sometimes polyurethane varnish) thinned enough with mineral spirits so they are easy to wipe on the wood. As with all varnishes, they harden well overnight so they can be built up to a very protective and durable film. There’s no need to wipe off the excess after each coat.
The first problem I came across in a magazine article was General Finish’s Arm-R-Seal being identified as oil. It’s not, and neither is Seal-A-Cell. Both are wiping varnishes. (So you may question why you’re instructed to apply both.) The fault for any confusion begins with the manufacturer, of course, and how it promotes these products. But we should know better by now.