Even though there is internet chatter about removing wax with 3rd party products, mineral spirits or vinegar, none guarantee success.
There is an old saying in the industry. "Once you wax, you cannot go back". Nothing adheres well to wax and even after cleaning, the wood grain can become contaminated. Wax can penetrate the wood, making future paint or stain finishes or touch-ups difficult or impossible.
The risk of a failure in re-coating over a wax finish is very high. Your best bet is to clean, strip, and sand, but even that is problematic. Here is what we recommend if you want to go ahead.
- Scrub with a solvent, such as mineral spirits, to break the wax barrier. Follow with several applications of Acetone applied with gray scotch bright pads to scrub the surface.
- Then strip the surface. You want to remove as much wax as possible before sanding to minimize the risk of driving the wax into the grain of the wood from the friction of sanding.
- Strippers that contain Methylyne Chloride like Zip Strip or Savograns are aggressive strippers but harsher. Gentler strippers are citrus or soy-based such as Citrus Strip or Soy Gel.
After cleaning, test the first coat of finish for adhesion. Rub a nickel across the surface or scrape the first coat lightly after 24 hours with a moderately sharp object such as a blunt standard table knife, not a sharp or serrated knife.
If you are finishing as a professional, NEVER guarantee a finish applied over wax. Here is a suggestion for your contracts:
We cannot warrant finishes over an existing piece of furniture. If products containing silicone (such as dusting sprays), oil soaps or waxes have been previously used on the piece, they may contaminate a new finish and prevent adhesion. In these situations, it is best to strip and sand the entire piece. Occasionally, a previous wax finish or silicone may be impossible to completely remove.
________ (Initials) I acknowledge that this piece has never been waxed/polished with a silicone-based dusting spray or cleaned with oil soaps.
________ (Initial) I have no knowledge of previous cleaning products used but realize they may have been applied by previous owners.
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I'm well-versed in wood finishing, restoration, and the complexities of dealing with wax-contaminated surfaces. The issues highlighted in the article are quite common when attempting to refinish wood that has been previously waxed. The challenges arise from the wax's ability to penetrate the wood grain, making subsequent finishing or painting a daunting task.
Removing wax from wood involves a careful process due to its ability to resist adhesion. Mineral spirits and vinegar might be attempted solutions, but their efficacy is limited. Instead, the article suggests a thorough approach, beginning with scrubbing the surface with a solvent like mineral spirits to break down the wax barrier. Followed by multiple applications of acetone using abrasive pads to further clean the surface.
Stripping the surface becomes necessary to remove as much wax as possible before sanding, as the friction of sanding can drive the wax deeper into the wood grain. There are various stripping options mentioned in the article, from aggressive ones containing Methylyne Chloride to gentler citrus or soy-based options.
The article emphasizes the importance of testing the adhesion of the first coat of finish after cleaning. Methods like rubbing a nickel across the surface or lightly scraping the coat with a blunt knife can determine if the finish adheres well, thereby assessing the success of the cleaning process.
Furthermore, the article advises against guaranteeing a finish over wax, especially for professionals, due to the risk of contamination. It suggests incorporating disclaimers in contracts to address potential issues arising from previous wax or silicone-based products applied to the furniture piece.
In the end, it highlights that sometimes, despite the best efforts, previous wax or silicone contamination might remain impossible to entirely eliminate, necessitating a cautious approach and realistic expectations when refinishing such surfaces.
