Identifying finish... Is this NC?

[marinosr]

I am having trouble figuring out what this finish is on this mid-century piece of furniture. I want to repair it. I thought it was nitro cellulose based on how brittle it was and the period it was made. I removed a chip and put it in lacquer thinner, though,band it didn't dissolve. It became springy in lacquer thinner but not gummy. No effect of DNA on the finish. Could this be NC that's just old enough it won't dissolve anymore? Or am I looking at some varnish?

 

[Gofor]

Did you try alcohol? Could be hand rubbed shellac.

 

[JNCarr]

Try pure acetone or toluene to eliminate the methyl alcohol and lights in lacquer thinner.
If DNA didnt touch it, its likely not shellac.

 

[marinosr]

I gave pure acetone a try... it made it springy but didn't dissolve it, like the lacquer thinner did. I have since read that many polyurethanes will swell and become springy with prolonged exposure to acetone. So I think I'm dealing with some sort of poly or other cross-liking varnish (which is surprising given the era of the furniture... it may have been refinished at some point.) Anyway, I scraped the old stuff off with a cabinet scraper tonight (it came right off, very brittle), sanded with 400 grit, and put some wipe-on poly in its stead... it's looking nice.

 

[Mike Davis]

A card scraper is my favorite refinishing tool.

 

[Oka]

Start with alcohol to see if it is shellac. If not then if you can test for polyurethane, Varnish and Lacquer – Use a cotton Q tip or swab with acetone on it and apply to the wood in a hidden or area not visible normally to the piece. If the area becomes tacky, then it is shellac or varnish and if it beads up, it has a polyurethane finish. If it is lacquer, it will dissolve almost completely.
It is good to practice testing with known finishes so you become familiar with how each reacts then, you will be knowedgable as to what finish you will be working with.

 

[Graywolf]

I am having trouble figuring out what this finish is on this mid-century piece of furniture. I want to repair it. I thought it was nitro cellulose based on how brittle it was and the period it was made. I removed a chip and put it in lacquer thinner, though,band it didn't dissolve. It became springy in lacquer thinner but not gummy. No effect of DNA on the finish. Could this be NC that's just old enough it won't dissolve anymore? Or am I looking at some varnish?

This seems like a conversation varnish from your description and the pic. Its not an easy repair. If this piece of furniture means something to you, then I would suggest you seek the assistance of a furniture refinishing and repair professional. If this a piece you want to practice on then you could try a host of technics.

 

[marinosr]

The repair is done. I scraped off the finish with a card scraper and wiped on satin poly. It looks much better now. Hopefully it will be durable. It's not a sentimental piece (bought it out of someone's garage), I just like it a lot and want to have it looking nice .

 

[Craptastic]

The glass cutting there is pretty damn nice. The whole piece is pretty damn nice. Good piece. I can see why you wanted to restore and were a bit picky on it. Nice work!

You found that at a garage sale? Damn! I need to find better garage sales.

 

[TheyCallMeTex]

Ahh a Negroni man I see!

 

[JNCarr]

That's a beautiful piece and well done on the refinish. Slainte!