What is the difference between....?


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Old 04-29-01, 10:36 PM
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Hi, could someone please tell me what is the difference between varnish, shellac & lacquer? How can I tell which one is on a table I have?
Also, the table in question is a hard southern pine, that had been stripped & then wiped with a watered down white paint. I guess like a white wash. Then some kind of finish put on that. I doesn't look nice at all & I would like to strip it down to the natural wood. Will it be impossible to remove the paint "wash"? It's like using a paint to stain the wood so I'm sure it was absorbed into the wood. Any suggestions?
Thanks.
 
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Old 04-30-01, 04:27 PM
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Varnish, either standard or polyurethane is a 'reactive' finish. That is, it cures by a chemical action. Once cured, the original solvent will not harm it.

Lacquer and shellac are 'evaporative' finishes. They cure strictly by evaporation of the solvent. Reintroducing the solvent to a cured piece done in either shellac or lacquer will dissolve the finish.

To test for a particular finish you start with the least durable - shellac. Dampen a rag in denatured alcohol (shellac thinner) and rub an out of the way spot in small circles. If the rag starts to drag or stick, the finish is shellac.

If this brings no results, try the same action in another spot using lacquer thinner. Again, if the rag starts to drag or stick, the finish is lacquer.

If neither of these tests yield any positive results, the finish is a varnish - whether 'standard' or polyurethane can only be determined by a chemical analysis.

If the person who applied the paint 'stain' sealed the wood first, you won't have too hard a itme cleaning it up. If they didn't, chances are you won't be able to clean it up enough to restain without some serious sanding.
 
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Old 04-30-01, 10:42 PM
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Now I know the difference!

George,
Thanks very much for explaining the difference between the 3 & how I can tell the difference with those easy tests. I keep a "reference scrapbook" of household hints, ideas & projects & a copy of your answer is going into it, for future reference.
I don't believe the wood was prepped in anyway before she (my mom)put the paint wash on it. I believe the very middle of the table is a veneer & I probably won't be able to do the serious sanding it'll take to clean it up. Maybe I'll just paint the middle & stain the rest of the table and matching pieces.
But, at least now I know how to find out what the finish on it is & know what to use to remove it. After that project, then I'll tackle the paint wash removal. One step at a time.
Thanks again, you've been very helpful,
Sandi
 
 

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