Understanding causes and remedies of this typically shallow damage.
by Bob Flexner
A friend sent me a web link to a video and short text recommending the use of mayonnaise to remove white water rings on tabletops thinking that I would scoff at this remedy. I didn’t. I’ve actually seen mayonnaise work fairly well.
But removing white watermarks is unpredictable. There’s no sure-fire procedure. Variables affecting the outcome include the type of finish, how old and porous it is and how long the watermark has been in it.
I wrote about methods for removing white watermarks in the April 2001 issue (#121) of Popular Woodworking Magazine. I don’t have much to add to those, but I can explain better why the marks happen – and knowing what’s going on in the finish helps in understanding the remedies.
Watermarks & Blushing
White rings caused by water are similar in their causes and remedies to blushing in lacquer and shellac. When you spray one of these finishes on a humid day, the finish “blushes.” It turns milky white. You can remove this discoloration in one of several ways: abrade through it using steel wool or other abrasive; spray a slow evaporating thinner, such as lacquer retarder, on top; or wait overnight. Sometimes it will disappear on its own.
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