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Old Varnish - Okay to use?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=41501		 Page 1 of 1
Author:  George L [ Thu Sep 26, 2013 11:04 am ]
Post subject:  Old Varnish - Okay to use?
I have a half can of Pratt & Lambert 38 gloss left over from previous finishing jobs. I've been adding marbles before re-closing the can after each use, but it's been sitting for a year or more now and I've found that despite my efforts at displacing the air, a thick skin has formed over the top of the varnish. Beneath that skin the varnish appears to be fine. Is it okay to use? I have an unopened can that I can turn to for my next project, but I hate throwing stuff like this out (or anything else, really). Just curious about what others would do in such a situation.

Thanks,
Author:  Rodger Knox [ Thu Sep 26, 2013 11:10 am ]
Post subject:  Re: Old Varnish - Okay to use?
I think that depends on how thick that skin is.
If it's less than 1/16" I'd test it on scrap to see how it dries, but I probably wouldn't use it on something for sale.
If it's 1/4" or more, I'd toss it.
Author:  nyazzip [ Thu Sep 26, 2013 11:14 am ]
Post subject:  Re: Old Varnish - Okay to use?
whether or not you discard it,you might as well at least use it on scrap, and keep the scrap laying around for a few years for observation....then you (and maybe we) will know for future reference.
i'm sure the general chorus here will be "throw it out!"
Author:  Colin North [ Thu Sep 26, 2013 1:40 pm ]
Post subject:  Re: Old Varnish - Okay to use?
I made a similar inquiry a couple of years ago and was advised to brush or spray a coat of the vanish on a sheet of glass and if it dried hard it should be OK.
Author:  Chris Pile [ Thu Sep 26, 2013 2:31 pm ]
Post subject:  Re: Old Varnish - Okay to use?
Next time, turn your can upside down. That way the skin is on the bottom of the can.
Author:  George L [ Sat Sep 28, 2013 10:51 am ]
Post subject:  Re: Old Varnish - Okay to use?
Thanks for the replies, fellas. I was swept up in a work project right after posting this question and have been unable to respond until now. Thanks for the advice. I'll definitely do some experimenting to see how the varnish performs.

Storing the can upside down is something I had considered doing in the future. However, if the thickness of the skin is an indication that the viability of the remaining material may be compromised, as Roger suggests, I wonder if it would matter whether the skin was on the top or the bottom. Any thoughts?

FWIW, of the varnishes I've tried, my favorite so far is the Pratt & Lambert. I've yet to try Epifanes or Sutherland Welles.

Thanks again for the advice,
Author:  Bob Menzel [ Mon Sep 30, 2013 3:45 pm ]
Post subject:  Re: Old Varnish - Okay to use?
Will be interested to see how your test goes. I've had Tru-Oil skin up on me (right side up and inverted) with no apparent problem. I'm planning on picking up a gallon of P&L 38, but will be transferring it into a couple of quart and pint cans for longer term storage. While I'm at it, I'll probably spring for a can of Bloxygen because I've lost all my marbles.
Author:  Rodger Knox [ Mon Sep 30, 2013 3:58 pm ]
Post subject:  Re: Old Varnish - Okay to use?
My observations about the thickness of the skin is based on my experiences with TruOil and the original Rockhard. Initally I didn't do anything to reduce the air in the bottle, so whenever I reopened the bottle, there was a little skin. I just removed the skin and used what was left, and didn't have any trouble with it until I got close to the last of the liquid, which didn't dry as quickly. It did still dry, but it took several days instead of several hours.
The Rockhard was in a quart can that was closed for a couple of months after being opened, and developed a skin nearly 1/4" thick. It didn't dry overnight on a test piece, so I tossed it.
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