Official Luthiers Forum!

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,

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George :-)

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.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

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!"

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.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Next time, turn your can upside down. That way the skin is on the bottom of the can.

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"Act your age, not your shoe size" - Prince

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,

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George :-)

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.

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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A man hears what he wants to hear, and disreguards the rest. Paul Simon