Turning Archive 2005

Yet another alcohol question - dilution

John K Jordan
>When soaking wood in alcohol, water is evidently mixed with the alcohol and then removed from the wood by migration and evaporation. Dave Smith's article mentions "the moisture content of the solution will increase".

Has anyone measured the amount of water in the alcohol after soaking one or multiple chunks of wood? If the amount of water steadily increases by some unknown amount, would that not decrease the effectiveness and repeatability of the procedure? Or in practice, do you lose so much alcohol each time that replenishing it keeps the solution fairly consistent?

I think I remember a straight alcohol/water mixture can be determined by specific gravity or perhaps calculated from heat of combustion (is there a chemist in the house?), but as impurities (extractives?) also appear to be removed from the wood and mixed with the alcohol, measuring the actual alcohol content might be more complicated. (The alcohol from my first test with small pieces of spalted oak burl turned quite dark)

Any data or thoughts on the effect of reusing increasingly diluted alcohol? At some point does the alcohol become saturated with water and cease to be effective in drying the wood?

And a side question: would not periodic agitation increase the water/alcohol mixing at the surface, disperse the more diluted mixture away from the pores, and effectively remove water from the wood more efficiently?

Seems like both of these would be fairly easy to test with a good set of scales, some "well used" and new alcohol, and a bunch of wood samples cut from the center of a large piece of wood.

JKJ in East TN

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