Keith, I have been reading your informative posts on finishes.  I've learned things from each.

What I have not read in awhile, though, is exactly where to begin.  Some years back;  most likely on a magazine forum now gone, a regular to restoration and finishes posted up an article on how to determine the existing finish on a piece.  I remember he had a small kit that he used containing some chemicals that he would use in a certain order that would provide the answer.  Maybe it was Jim Kull, or maybe Steve Mickley.  But I looked through Steve's site without seeing anything like this.

 

Maybe you could do an article or two on restoration?

Full disclosure - my wife bought an old dining table and expects that I can "make it new again".  Not without some guidance I can't!!!

Cal

I used to have a bottle with a dropper that was "Finish Indicator".    The result and color of the puddle would indicate broad classes of finish.   I used it so little, it went bad.

 

But the test I think you are referring to:

1.  Put a drop of denatured alcohol on and obscure spot and wait for a minute or so.   If the finish is soft and sticky, it's shellac (shellac's solvent is alcohol).    This is not entirely foolproof, because alcohol is a latent solvent of lacquer and if the lacquer is really old, it might soften it a bit.

 

2.  If it fails #1, put on a drop of lacquer thinner and repeat the test.   It will soften lacquer.   But again, the thinner may contain some strong solvents like acetone that can also cause some damage to varnish and waterborne finishes.

 

3. Xylene does the same for w/b finishes, but an old piece is unlikely to have that.

more:  http://www.woodmagazine.com/materials-guide/finishes/what-finish-is-that-anyway

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Probably the best rules of thumb:

Made before 1910 : shellac most likely for home-built and factory finished furniture

Between 1910 and 1940 : shellac being phased out and lacquer taking over

Post 1940: 99% chance of lacquer for factory finished furniture.   Varnish likely for shop-built.

 

some other advice:

 

Products like Formby's Furniture Refinisher seem to be just a glorified ATM (Acetone-Tolulene-Methanol) stripper.   It contains solvents for both lacquer and shellac.  My opinion: buy some lacquer thinner and save yourself money -- it's the same ingredients, in maybe different percentages.

 

Howard's s Restore-a-finish seems to be just a glorified furniture polish with some alcohol to remove white water rings.   I've used it and it looks good for a few weeks, turns bad again.   My opinion is antique shops use it to put "lipstick on the pigs" and when a customer buys a piece and comes back in a month with a dull piece, they have the opportunity to sell them a can of Howard's

 

 

Edited August 1, 20178 yr by kmealy

Thanks Keith, as my start date approaches for this project I will likely have a few more questions for you!

Cal