An explanation of this most confusing of finishing treatments.
In the late 1980s, I hosted a local call-in radio show dealing with finishing and restoration. I remember one caller explaining that he had applied four coats of tung oil; he asked what he should use to seal the wood!
OK, so he was probably using wiping varnish falsely labeled “tung oil,” as I’ve explained many times, but four coats of any finish will seal wood quite well. Just one coat, in fact, is enough unless the finish has been excessively thinned.
Clearly, this fellow misunderstood the term “sealing.” But he’s not alone; there’s probably no term in finishing that’s more misunderstood.
A Little History
In the 19th and very early 20th centuries, there was no discussion of sealers and, so far as I can determine, there were no products marketed as sealers.