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  #11  
Old 25-03-09, 06:00 PM
Koo Schadler's Avatar
Koo Schadler Koo Schadler is offline
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Hello UBI,

Yes, shellac processed for furniture finishing is generally warm and dark in tone, and should be avoided. That is why you must make your own from scratch, with the proper bleached crystals.

David, I have a few questions for you. I've been using the bleached shellac crystals from Kremer and Natural Pigments. I did a test strip over different colors perhaps ten years ago that I've watched age, and have yet to see any perceptible yellowing to it, so thus far I've been satisfied with it. But from what you've said the clear would be even better. I wonder why Kremer et al don't carry it? If anyone would want the least yellowing shellac it would be a painter.... Is the music store you mention the only resource you have found for it? And how do you dissolve their shellac, which looks like it comes in sticks? Thanks for this link.

Also, how does one distinguish a less than pure denatured alcohol? Finally, have you (or anyone else) tried the water based shellac mixture from Natural Pigments.com? It is less toxic (given its water versus alcohol base), already dissolved, and in a convenient spray jar. I ordered a jar but haven't tried it yet.

Once I did remove shellac from atop an et painting. I inadvertently laid a small pond on a finished piece, leaving a too thick and uneven surface. After a few days of a minor freak out, I girded my loins and dove in for the repair. It actually came off well - as mentioned, denatured alcohol is a solvent for shellac but not for tempera (although conservator Ross Merrill warned me that too much rubbing of denatured alcohol atop tempera could eventually start to lift up some of the egg oil and maybe jeopardize the paint, so use it judiciously). Using a soft cloth dipped in alcohol, I wiped very very carefully until the shellac was all gone, then let the painting rest for a few days, and then successfully shellaced again. So it worked, but the shellac was relatively fresh when I removed it. I didn't know that shellac became insoluble over time, which is good to know about.
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  #12  
Old 25-03-09, 09:01 PM
dbclemons dbclemons is offline
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I just used the link to show that clear shellac is genuinely clear, but I should declare that I never bought anything from Music Medic. Their shellac would be dissolved just like any other. Extra bleaching makes it more expensive than other types, and most wood workers don't need clear shellac. Artist's use of shellac would be a very small market. The last place I bought some clear shellac seems to be off-line now.

I never use shellac as a final finish. I do have some unpainted test papers that I've sized with shellac that look rather clear after several years, even though I used a light blonde variety. I sometimes use it as a isolation layer in casein painting, but it all gets overpainted, so a slight tint doesn't bother me.

Generally, shellac is insoluble in water but water-based shellac is made by pulverizing shellac into a fine powder, and boiled down with water. It's used for inks. Emulsifiers or humectants can be added to keep it liquid. I believe Kama sells this also.

Alcohol (ethanol) can be denatured by many different things, even gasoline. "Denatured" just means it's been made unsafe to drink. Some cheap varieties may have contaminants present including water, which in small concentration are not enough to declare on a label, but COULD effect shellac causing it to get gummy. 200% proof is considered pure ethanol. It's something that's strongly regulated since it's used in illegal activities like meth labs. This is one reason that getting a dealer to mix it for you is reasonable, provided you know what you're getting.
More info about alcohol:
http://www.pharmco-prod.com/pages/alcoholintro.html
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  #13  
Old 31-03-09, 07:42 AM
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UBI UBI is offline
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Koo and David
Thank you for reply.

I'll try making my own varnish from extra-clear resin.
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