A reader thought he remembered my cautioning against applying paste wax over water-based finish or latex paint. His memory was that I had said that paste wax could damage these coatings.
This is not true, of course. There’s no problem applying most paste waxes over water-based finish or latex paint. But the source of the confusion could still be me because I have said that one brand of paste wax, Briwax, could cause damage.
Traditional Briwax contains toluene (toluol), which is a strong, fast-evaporating solvent. Toluene will damage water-based finishes, latex paints and also varnishes and lacquers if they aren’t fully cured.
My experience with Briwax goes back before it became popular, maybe even before it became available in the U.S. An antique dealer across the street from my shop brought me back a can from a buying trip to England. She loved this paste wax because it dries so fast that it can be buffed out almost immediately – in contrast to other paste waxes, which require much more time for the solvent to evaporate. The fast evaporation, of course, is the consequence of the toluene.
More recently, Briwax has had to add a toluene-free paste wax to its line of products because of environmental concerns with the toluene. But this new version still contains xylene (xylol) in addition to naphtha, both of which evaporate slower than toluene. Importantly, these solvents, especially xylene, are still strong enough to cause damage.
So be cautioned if you like using this wax for its easy workability.
— Bob Flexner