How much epoxy curing before painting?

Is there any official recommendation on how long epoxy needs to cure before being over-painted? 

This the outside hull of an NE Dory and will be Interlux Pre-Kote over MAS.

MAS says thin film set and full cure take seven hours and seven days respectively, and Interlux only talks about prepping with 80 grit and cleaning up blush.

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RE: How much epoxy curing before painting?

I don't know about official, but you need the epoxy to be completely cured where it contacts the paint so you don't have unreacted components contaminating the paint. That's probably what the thin film set refers to. If so, that's the absolute minimum for the roughest workboat finish.

If you're trying for anything nicer, you'll want to be sanding it, so it has to cure hard enough for that. Seven days is a good average guess, but depending on your local conditions it can be a lot more or a lot less. The safest thing is to wait until you can't dent it with your thumbnail, then try to sand it. If it makes a dry dust, you're fine. If it balls up and clogs the paper, it needs to cure some more.

MAS is a no-blush epoxy, but it doesn't hurt to clean the surface with water and denatured alcohol to remove any contaminants, including sweat and skin oils.

FWIW, my sailing dinghy took 30 calendar days of sanding, filling and priming to go from final epoxy coat to start of paint (this was mornings before work and weekends).

Have fun,



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