> Manufacturers, not unlike boat builders, want the world to work the way
> they want it to not the way the world wants to.

> If you want to believe System Three's statement of unlimited life, do so.
> It is clearly wrong.

> My statements may be wrong but I error on the safe side. Personally I use
> about 10 gallons of epoxy a year, I purchase new epoxy each month and
> discard the old.

In principal I agree, George, but would take issue with some of the details. I installed a 4500 sq ft epoxy floor once with material that turned out to be 7 years old! I wasn't in on the joke before the fact and changed suppliers after that stunt, but the point is that the location is a very high traffic area on a pedestrian ramp of a major Seattle parking garage, and after 6 years it's still in good shape. I wouldn't recommend this to anyone, and it certainly is no guarantee of anything, but it illustrates that there is more flexibility to shelf life than you might think. I wouldn't think twice about using high quality 1-year-old material if in undamaged original, unopened containers.

Industrial seamless floor applicators tend to amass stocks of surplus material over the years, because with material you can't get locally you need a safety margin. We had +/- 600 gallons of cats and dogs last year, from +/- 25 different manufacturers, mostly partial kits of opened material, and because of environmental concerns it costs $17 per gallon to DISPOSE of surplus epoxy around here. We thought we had a deal to sell it all to a cement operation for kiln fuel for $0.02 on the dollar, but they backed out because of the huge variety of material types. If you mix it up and cook it off though, it becomes nonhazardous. So we mixed it all up in small batches, added sand and made mortar out of it, and trowelled it down underneath a new driveway. It all set up hard as a rock, and some of it was 22 years old.

So, I think tossing it out after 1 month is a waste of good material.