>I posted this on the main forum but wanted opinions from turners. In my spare time I turned a small bowl from California Laurel. The wood looked like it would have some interesting contrast, but when I applied the blonde shellac the contrast kind of melted away and the piece took on a grey cast. Any help or suggestions? I have thought that I would sand the finish off completely and wait until I can get some oil to bring the grain out and then apply the shellac, or perhaps I should sand and then apply Deft.
>What you are describing could be the result of blushing, moisture trapped under or in the finish; not an uncommon problem in these hot and humid days of summer. Shellac is little different from lacquer with the blushing problem, and it can happen whether it is sprayed or brushed when the conditions are rught. The rapid evaporation of the thinner lowers the temperature of the surface film to below the dew point of the atmosphere, and condensation is formed the finish as it dries.
You can slow the evaporation rate of the alcohol thinner with the addition of a little Turpentine. Use the real Gum Spirits, and not a substitute. About 2-teaspoons per quart of alcohol should do it.
A couple other things.
Was the wood dry?
Wood moisture can be a problem.
Was the shellac old??
Or, did you mix a fresh batch with old alcohol??
Either way, the result can be the same because the alcohol can absorb large quantities of moisture from any exposure to the air. The rapid evaporation of the alcohol in hot weather will cause this moisture to condense out and form the blush.
>Thanks, Russ. I think you hit it right on. Our weather has been extremely humid lately and I didn't even think of the problem with moisture and shellac. It was fresh blonde shellac made from flakes (the only finish I didn't sell at my auction). I wiped the shellac off, sanded again and then thinned the shellac and applied it again and everything looks cool. Again thanks for your accurate diagnosis.