Why does nobody talk about the primer flash time on aluminum?

I keep seeing guys at our shop spray epoxy over aluminum panels after just 20 minutes, then wonder why the top coat fisheyes. The tech sheet for our primer says 60 minutes minimum flash time for aluminum, and I've tested it. After three separate jobs last month, I started clocking it. The ones I let sit a full hour laid down perfect every time. It's not a big thing, but it saves a ton of rework. Anyone else find small tech sheet details that get skipped a lot?

2 comments

2 Comments

walker.logan27d ago

The shop temperature gets ignored too. Our tech sheet says 70 degrees for that 60 minute flash. If it's 55 in the bay, that hour might not be enough. I watched a guy follow the time but the metal was cold to the touch, and we still got solvent pop. It's not just a timer, it's about the conditions hitting that dry stage.

ruby_gonzalez26d ago

Man I used to just set a timer and walk away, no questions asked. Seeing solvent pop happen right after a "correct" flash time was a real wake up call. Now I always check the panel temp with my hand before moving on, it's just part of the job. That tech sheet number is a goal, not a guarantee if your shop is freezing.