I have been experimenting with shellac as a finish, and for the most part have been pleasantly surprised. I have encountered one issue that concerns me, and so am wondering if anyone has any advice or insights.
I mixed up a 1 lb cut of dewaxed blonde shellac using an industrial “anhydrous alcohol” (approx 70% ethanol, 30% methanol, 0.5% ethyl acetate), and my 1/2″ thick maple drawer sides cupped in a rather extreme manner when said finish was brushed on one side. Thinking this might be due to moisture, I wiped the second side with water, and this helped flatten the parts. They never were as flat as before, so any advice that allows me to avoid this stressful situation would be much appreciated.
Thanks in advance, Andrew
Replies
odd
I have used shellac on several projects, but have never seen any cupping as a result. I use plain denatured alcohol from a Big Box store.
So I can't advise you on the cause of your cupping, but I do advise you to not use this anhydrous alcohol due to its very high methanol content.
Methanol is higly toxic and is easily absorbed through the skin.
Forrest
Thanks for your input Forrest, and for the warning about the toxicity of methanol.
It is however my understanding that most 'denatured alcohols' contain significant amounts of methanol due to its toxicity and the fact that its boiling point is close to that of ethanol, thereby making them difficult to separate by distillation.
Andrew
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