09-04-2010 05:29 PM
Zinsser used to put the date of manufacter on the bottom of the can, so you could figure it was good for three years from that date. They don't do that any more, just a code. Is it still good for 3 years, and is there a way to decipher the code?
09-04-2010 06:49 PM
Three years was very optimistic. I hadn't noticed the lack of an open date, it must be a recent change since the TDS for the Amber still refers to a date stamped on hte bottom.
09-07-2010 08:11 PM
My local retailer only carry the one gallon of dewaxed shellac. After 2-3 years, the gallon always starts to leak from the bottom. It happens to me with the last 2 gallons I bought.
09-08-2010 05:24 AM
Zinsser has had problems with the interior coatings on a number of their cans. Shellac is acidic and eventually eats through the seams of the can.
Frankly, despite Zinsser's specified storage life after two years, and especially after three, I would be pretty reluctant to use shellac that old. I'd be looking for a source where you can buy it in quarts so you could be workinhg with fresh shellac. Or, order flakes and mix your own. Better quality, usually, and you only need to mix what you need, so you know it is really fresh.
09-15-2010 08:36 PM
I left the can outside, and it has drain itself, if it was at the bottom of the can, nothing is readable anymore. My estimate, it was 4 years or older. The can was never left on a concrete floor as an example, where the humidity may make it rust from beneath. It was 4 feet off the floor, on top of a file cabinet (4 drawers) that I use to store my tool and the paint in the top drawer. It is dewaxed shellac, that I use as a first and 2nd coat when I finish my project. Then, I give it 4-5 coats of water based poly-urethane. The shellac enhance the grain color, without yellowing the wood.
It happed with a previous gallon I bought 3-4 years prior to this can. The previous gallon leaked all over the top of the file cabinet, removing the paint in the process.