Just realized I was sanding clear coat way too early for years

Used to wait maybe 15 minutes after spraying before hitting it with 800 grit, but after a bad run last month where it all peeled, I tried waiting a full 45 minutes and the finish came out way smoother. Anyone else rushing their flash times and getting burned?

3 comments

3 Comments

thomasgonzalez4d ago

You say waiting 45 minutes gave you a smoother finish, but I actually think rushing it can work just as well if you keep your coats light. I've been spraying for years and I still hit it at maybe 10 minutes with 600 grit and never had peeling issues. Over waiting just makes the clear coat too hard to sand smoothly without heavy scratches.

brooket434d agoTop Commenter

...and that's kind of the thing, right? It depends a lot on what you're shooting. I did a project a few years back on a vintage motorcycle tank - single stage urethane, not your typical clear - and if I'd waited 45 minutes that stuff would have been like trying to sand a rock. 10 minutes with 400 grit was the sweet spot for that particular paint, any longer and you were just making deep scratches you'd have to fill later. But I've also done plenty of basecoat/clearcoat jobs where 45 minutes was just right because the clear was still soft enough to level but not so soft it loaded up the paper. It's almost like you just gotta feel it out with your own setup and not get stuck on a hard rule.

mark_green4d ago

@thomasgonzalez I get what you're saying about light coats, but your paint is basically still wet at 10 minutes. That 45 minute window lets the solvents flash off just enough so the clear has some bite without being gummy. Light sanding on a fully set clear with 800 or 1000 grit gives a way more consistent finish with no deep gouges.

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