CP140: Thanks for the chemistry lesson. I have a degree in Biochemistry, but I'm sure there are some out there that this helped.

To all: Everyone discussed the "alcohol" thinner, but what about turpentine or mineral spirits? I can't find any performance data on these as thinners, so I expect they are unacceptable. Turpentine is distilled from pine resins, so it probably has very good penetration of the wood, but might affect the wood fibers before it evaporates out. It also has a much lower vapor pressure than isopropanol, so it might not ever fully evaporate. Mineral spirits may even be more problematic, since I believe they can be used to dissolve and loosen epoxy (used as a mold release in some epoxy casting methods).

Any actual experience with either of these? Perhaps its time to conduct some experiments in "the lab," otherwise known as my basement workshop!

Thanks,
Brad