How to identify an existing finish.

[Anotherplane]

Hey folks,

I recently bought a Georgian bureau bookcase circa 1800 for a restoration project. I knew upon initial viewing the finish on the side of the piece looked a bit shiny and plasticky. This morning I just tried a little metho on the finish and it didn't dissolve or turn sticky so I'm guessing this is something modern. I also tried reviver with equal parts metho, linseed oil and turpentine which is stronger on metho than I usually use....it didn't make any difference even using 0000 wire wool...

Can anyone advise on the best way to approach this, do I test with a different solvent or just dive in and strip the piece. The existing finish is obscuring the nice mahogany and not showing it off at all so I don't feel like it would be destroying a nice patina.

[jack620]

I had a similar issue with a gramaphone record player. Metho wouldn't remove the finish and it was too old to be polyurethane. The finish was murky and dull. I ended up stripping it with paint stripper. I did a small section at a time and wiped off the residue with copious amounts of metho. Then I refinished with shellac. A dramatic improvement.

[Anotherplane]

As much as I hate to have to strip it I think it's the best option as there is some nice mahogany hidden underneath.

I think the piece must be quite a bit earlier than the auctioneer suggested. The oak lined drawer bottoms run front to back, the dovetails have a half tail at the bottom. The ogee feet are almost identical to a 1750 bureau bookcase I saw online, It's going to take quite a bit of work but it's a piece I will be keeping for a long long time.

[q9]

Try acetone and steelwool.

[Anotherplane]

I am really surprised at the resilience of this finish, I have used mineral spirits ( white spirits ), metho, polish reviver, acetone all applied quite vigorously with 0000 wire wool and it makes hardly any difference. It did however knock off the horrible plasticky shine and it seems the grain is showing better. I applied beeswax over the cleaned area and it is good enough that stripping the finish is maybe not now the best idea...

[ED65]

I had a similar issue with a gramaphone record player. Metho wouldn't remove the finish and it was too old to be polyurethane. The finish was murky and dull.

Aged shellac is occasionally resistant to being redissolved in alcohol, you see this sometimes if it has 'alligatored' for instance.

When dealing with furniture of the right age to originally have been finished in shellac (pre-1930s) if ethanol or meths literally won't touch it there's a decent chance it was previously refinished, or at least had the finish topped up, since you can scuff shellac and successfully put virtually any other clear finish over the top of it.

In this case that might have been an old copal or dammar varnish, which are good candidates for going murky and dull!

[ED65]

...I don't feel like it would be destroying a nice patina.

If you have to remove old finish stripping is the way to do it and retain as much of the original colouring as possible, the patina which is in the wood and not in the dirty or discoloured old finish. With minimal abrasion and sensitive refinishing you can make it look like nobody ever messed around with the thing, as is the often the goal of professional restorers naturally.

I am really surprised at the resilience of this finish, I have used mineral spirits ( white spirits ), metho, polish reviver, acetone all applied quite vigorously with 0000 wire wool and it makes hardly any difference. It did however knock off the horrible plasticky shine and it seems the grain is showing better.

Plasticy sheen, resistant to acetone and abrasion? That does sound suspiciously like it was refinished, with a two-part product, so fairly recently as you initially suspected.