Catalyzed Finish Expiration Dates

      Pre-cat lacquers are labeled with an expiration date. Use it after that, and here's the trouble you'll have. June 28, 2006

If I go past the pot life on my precat laquer (1.5 years old) but it seems to spray fine, what are the possible negative effects that I can run into? Also, what is a safe shelf life for precat?

Forum Responses
(Finishing Forum)
From contributor A:
The catalyst has been used up past its pot life. It will no longer cross link and produce a good hard finish. It will still work like it should except the durability rating of the dried product will be diminished. You might as well use nitrocellulose lacquer.

From contributor B:
Most of my precats are 6 months. I tried using one past that, and it came back all checked. It was the only one I had all year. It is best to check with your coatings supplier to see if something bad will happen.

From contributor C:
When I used expired pre-cat the first coat was alright , but the next coat made the first coat wrinkle. What an ugly mess that was. Live and learn.

From the original questioner:
How do I know when it was originally catalyzed? Is it six months from the time I open it or the manufactured date?

From contributor B:
It would be six months from manufacturer’s date.

From contributor A:
Mine sits on my distributor’s shelf uncatalyzed until someone places an order for it. Then they add the catalyst and shake it up. After that I have 3-4 months to use it. I use ML Campbell's MagnaMax.

From contributor D:
There are some companies that add the catalyst right into the coating, and there are others that add the catalyst when the coating is shipped. Some are sending the catalyst with the coating and the finisher does the mixing. Normally, something that old, where the catalyst was added right into the coating, would have gone through the crosslinking process already, and would have hardening right in the container. You should ask your manufacturer or supplier, then date the cans so you know the expiration dates.

From contributor E:
I've used Magnamax 3 months past the expiration date. It worked fine but I will say it wasn't as durable as the catalyst was petered out. It took twice as long to cure. We keep the cans around for a year in case of a call-back touch up, then we pitch them in the proper method.

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