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Wetting to Predict Blotching

Jul 7, 2016 | Expert's Corner | 0 comments

You can usually get a pretty good idea whether or not the wood you are using will blotch when a stain or finish is applied by wetting the wood.

You can use any liquid, but water will raise the grain causing you to have to sand more. Mineral spirits (paint thinner) works well except if you intend to apply a water-based finish. Some residue oiliness may remain and cause the finish to fish eye—that is, bunch up into ridges rather than level out.

Denatured alcohol would be better for this situation because it will totally evaporate. But it evaporates quickly, so you don’t have much time to judge the potential for blotching.

One possible solution would be to wipe with mineral spirits to provide more time, then remove the oily residue by wiping with denatured alcohol