List - Regarding the use of different alcohols for thinning shellac, my understanding is that grain alcohol, as Susan suggests, and "reagent" alcohol, a laboratory-grade denatured alcohol, are preferred. And Susan also alluded to (I think?), a product offered by Russ of www.woodfinishingsupplies.com that is called Low-Odor 200 proof Denatured Alcohol. I have used it on my last three piano jobs and it is a great product. Regular 'denatured alcohol' found at paint and hardware stores is adequate for shellac thinning, but it does contain some contaminants and more water than the others listed above (perhaps in the 10-15% range, I am not certain). I have used it numerous times when convenience was an issue. The dry times are longer, and it doesn't 'lay out' as well when spraying. It is also more prone to blushing. It is more valuable to me to use for cleaning the brushes or spray gun after applying shellac, or to use in cleaning the wood surfaces I am finishing. One thing to keep in mind... no matter how pure the alcohol is when you start, it will draw moisture from the air if left in an open container for any length of time. Mark Potter bases-loaded@juno.com On Tue, 4 Sep 2001 18:11:02 EDT A440A@AOL.COM writes: > David asks: > >Why use grain alcohol that has some water in it and would seem to > have > >some > >counterproductive properties Why not use denatured, or does it > have water > >in it too? > > Greetings, > The "denatured" aspect of alcohol is related to the poisonous > additive, > which allows it to be sold without the liquor tax. This type of > alcohol is, > if I rememberr my high school chemistry class, is commonly about 40% > water. > The grain alcohol sold at the liquor store is 190 proof, which is > 95% > alcohol. If you try to take it to the purest state of 100%, it > will break > down into water/alcohol mix of about 95%. Which is enough to make > it dry. > Anhydrous alcohol is difficult to keep that way, i think it > takes a very > low temperature. > Regards, > Ed Foote > >
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