PSA - Old can of shellac

[skizzo]

Putterring around in the shop today, mostly bandsawing, jointing and sanding, and something didn't seem to smell right. I checked around a bit and eventually chalked it up to lots of operations on different wood species. Eventually made it over by the bench and storage cabinets and it smelled more and more like shellac. Hmmmm.... haven't done any finishing inside all summer and haven't used shellac since I don't remember when. But I opened up the upper cabinet with cans of finishes and paint rattlecans and found shellac had seeped over half the lower shelf. The quart can that's been sitting there for a couple years or more somehow degraded or sprung a leak, leaving a layer of gooey mess about 2' around. Quick run to the store for some DNA and it all cleaned up, with the can immediately discarded.

Just a heads-up that the shellac/alcohol seems to have eaten its way through from the inside out of the stored can, breaking through over night last night. Glad I was back out there today and found it soon, and thought it might be a good reminder for others to keep an eye out.

[Paul K. Murphy]

That's a good ending to a story that could have been much worse. Fortunately, alcohol contained in shellac isn't the fire hazard other volatiles can be. That's why alcohol stoves are a good choice for boats. A heavier than air cloud, lingering, is the last thing you need!
Glad things worked out well for you.

[K. L. McReynolds]

Shellac has a definite shelf life. Once that shelf life is up, shellac does it's best to get off the shelf.

[skizzo]

[AgGEM]

Skizzo - Thank you for this PSA!
Ag

[YSU65]

Happened to me too. Going to put the new can in some kind of plastic container just in case it happens again. Mine was pretty old, probably 7-8 years.

[Guest]

Me too. What a mess! I now decant Seal Coat into a mason jar as soon as I open the can. I keep the jar in the back of a dark shelf so the UV is not a problem. One would think Zinssner would know about this problem and package their product in something that doesn't deteriorate over time.

[DaveinOhio]

Hank Knight in SC said:

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Me too. What a mess! I now decant Seal Coat into a mason jar as soon as I open the can. I keep the jar in the back of a dark shelf so the UV is not a problem. One would think Zinssner would know about this problem and package their product in something that doesn't deteriorate over time.

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The main problem though is that the premixed shellac will itself deteriorate over time. I try not to keep any of those type of products(finishes, glues) more than a year after the purchase date.

I always keep at least a spray can of shellac on hand for general use, but one of those generally gets used up within a few months. Otherwise, I try to buy finishing products shortly before using them, and will discard the unused portion when winter really sets in.

Dave

[fredhargis]

This seems to be a common problem, I now put my cans of shellac into plastic bags and then sit them o the shelf. For the record, I also had this happen with some Watco NC lacquer. The can became corroded enough to let all of it leak out. Fortunately it was stored in the barn, so there was little damage, just a huge mess.

[J-W-P]

This happened to me too a few years ago. Little pin hole leak formed on the side of the can. Of course the hole was near the bottom of a nearly full can.
The drawer I kept the can in now has a thick layer of cured shellac with a hole in it the size of a quart can.