Preserving Leftover Catalyst

How to prolong the shelf life of unused catalyst for catalyzed finishes. March 12, 2006

We use post-cat polyurethane for spraying wooden counter and island tops. We're fairly satisfied with the final product, but the problem is the shelf life of the catalyst. We've used ICA and have been told by Campbell's reps that their cats will do the same - a month after the cat is opened, it is spoiled. We only use it on occasion, like 5 times a year (less than 2-3 gallons). Any solutions?

Forum Responses
(Finishing Forum)
From contributor R:
Most companies have catalysts available in quarts/liters. Build the cost of the wasted catalyst into your price.

From the original questioner:
Thanks. I actually have 0 control over pricing, but I'd for sure do that. I think the owner already does. We've been told that if you shoot inside the opened container of catalyst with a product called "Bloxygen," it will skin over the top and keep what's under it fresh. Also been told to toss it in the freezer (right next to the squid and cigar minnows).

From contributor D:
Use Bloxygen. The only way an isocyanate catalyst goes bad is by moisture absorption. I use argon from my MIG welder for this purpose, but Bloxygen works great too. Here in the desert (Phoenix, AZ), this is not much of a problem with 15% humidity, but back in Pennsylvania using a shielding gas was absolutely essential. One squirt and the activators should last forever.

From Bob Niemeyer, forum technical advisor:

That's right - use an inert gas like Bloxygen. Also, don't keep small amounts of product in larges cans with lots of air space. Pour it off into a smaller can and float some inert gas that is heavier than the air we breath. Also, placing cap on can when not in use will help.
Please don't place it in the freezer - that's a no-no.