Sorry never gave that a thought about block sanding. You said it gets really hot then the better off you are. I have had problems with painting fiberglass parts as soon as i get them. Now maybe each company is different. Just make sure you let the primer set long enough to cure. Id let it set over night or if it does get that hot where your at set it out side but be careful to much heat at a long period of time is also bad for the primer & paint. Sorry dont mean to scare ya. We also want pictures lol
