Usually the spraying conditions aren't affected by the shelf life, so much as the performance of the product after it is set up.
My PPG jobber tells me that DCX61 should be used up within 12 days after opening, and they told me the same about the reactive reducer used in the DRR basecoat system. I switched to DBC to avoid that shelf life issue.
I've seen freshly spayed PPG2021 Clear that is difficult to compound that the jobber blamed on "old" hardener. I'm sure the DCX61 was only a couple of weeks old.
It's a bit frustrating, because in restoration, paint jobs tend to be quite spread apart, as compared to a production collision shop that might spray color a couple times a day, every day....
Tim Bowers
Stellar Antique Auto Restorations.
