Shellac ... Waxed or Unwaxed
Issue: Issue 3.24
Posted Date: 12/17/2002
Though he'd only had one failure with waxed shellac, this woodworker had heard a lot of talk about de-waxed shellac, and wondered under what circumstances waxed shellac would cause problems. Otherwise he's had great success adding wax (seed lac) to his shellac ... using it thick under marine spar varnish, and under oil or latex paint ... and has found it best as well for French polish.
Mixing waxed shellac with waterborne-finish topcoats is a sure formula for disaster, noted one response. He noted that the label on his favorite brand of Oxford waterborne emulsion lacquer and poly specifically instructed against the use of waxed shellacs because of adhesion problems. Surprised to hear about some "adding" wax to shellac, he related his understanding that the higher the wax content, the lower the resin strength, the softer the film strength, and the more susceptible it was to water and heat.
Another poster likes to start with dewaxed raw shellac, because he can exercise total control over whatever he adds to it. That may be a retarder added to a first coat (which he wipes dry while still wet and then buffs when dry), turpentine or mineral spirits added as a thinner, or wax for a French polish. For the latter application, he's found that wax added some flexibility to the film and prevented it becoming brittle with age. He also saves any settled wax for subsequent applications.