Issues when spaying SPI epoxy

RayH

Promoted Users
Hi guys, new to the forum. I just sprayed some SPI epoxy and had some issues with fisheye/ craters ( assume it was application issue when spraying) . I used the waterborne cleaner and let it set for an hour. I mixed the epoxy and let it induce 30 mins. The issues showed up on the first coat. I let the first coat flas for 1 hour and then applied a second coat ( went much better after spraying faster and less overlap) anyways my question is do I wet sand the expoy to smooth it out and move forward with applying the 2K primer or do I need to spray another coat of epoxy after sanding before primer?
 
The craters come from spraying the epoxy too wet on the first coat. First coat needs to be sprayed fairly dry. Your subsequent coats can be wetter. If you are applying 2K urethane, you don't need to do anything about the craters.
 
Hi guys, new to the forum. I just sprayed some SPI epoxy and had some issues with fisheye/ craters ( assume it was application issue when spraying) . I used the waterborne cleaner and let it set for an hour. I mixed the epoxy and let it induce 30 mins. The issues showed up on the first coat. I let the first coat flas for 1 hour and then applied a second coat ( went much better after spraying faster and less overlap) anyways my question is do I wet sand the expoy to smooth it out and move forward with applying the 2K primer or do I need to spray another coat of epoxy after sanding before primer?

Dry sand the epoxy. For best results, wait 48 hours before sanding. There are two types of adhesion, mechanical and chemical. Mechanical adhesion is created by sanding scratches. Chemical adhesion is created by the product fusing/bonding to the layer of paint being sprayed over. It is said that chemical adhesion is better than mechanical adhesion. Since SPI epoxy has a 7 day window, if you apply any other material, filler or paint, within that 7 day window, you will have chemical adhesion. I believe if you sand within the 7 day window and apply another product, you're getting a chemical and mechanical adhesion. It would be best to apply 2k primer over epoxy after 48 hours, and within the 7 day window.
 
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Guys thanks for the advice! Chris you stated the first coat needs to be sprayed fairly dry but the tech manual states 2 wet coats ( I know it doesn’t mean 2 at the same time).
I plan to wait 72 hrs, dry sand with 180 and apply the 2k.
 
As was pointed out to me by a friend on the forum here, you can spray wet but you have to maintain correct gun distance. If you get the gun too close or too much overlap on a pass you get the craters. I guess I have tried to simplify it for everyone with my answers about spraying lighter.
 
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