Q: I stained cherry with Minwax oil based stain and finished with compatible Minwax waterbased varnish. Over time the surface has developed what appear to be oxidized areas of light color. I have tried to fix these by sanding the surface, re-staining and finishing with oil based varnish but the blotches reappear. How do I resolve this problem and what has caused them?
A: The answer to the first question depends on the answer to the second. If the light areas are on the surface of the clear or in the clear finish itself, they may be simply blush marks. You can remove blush by spraying the area with blush eraser, which you can buy in aerosol cans at most woodworking specialty stores. However, the white marks may also be delamination, and that’s fairly common when pairing waterbased topcoat with oil based stain. Yes, the two are compatible under ideal conditions, but push the envelope just a bit and you get problems.
The most likely causes of delamination are not wiping off the stain aggressively enough, since it must be wiped completely while wet leaving only what the wood has absorbed, or applying the topcoat without leaving enough time for the stain to dry completely. By the way, if you in fact put a coat of oil based finish over the waterbased, the blush chaser will not work. Once you’ve done that, the only solution is to strip the piece and start over again, which is also the best solution for delamination issues.
Q: A few years ago I applied Watco oil to kitchen cabinets and put Watco satin wax on top of the oil. Now I want to renew the Watco oil and then seal with Varathane. How do I get rid of the wax?
A: Scrub off the wax with mineral spirits on a nylon abrasive pad, and wipe up the resulting slurry with paper shop towels.
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