Yep, Cut the gel coat with acetone until you get the spray you like. Test spray on smooth vertical surface - no runs. Use a good, good bit more catalyst then you think. Get the scratch onto the horizontal if possible. If not, wait 10 minutes or so between light coats - no sags... no over spray outside your tape off... Clean the scratch super well with acetone. Tape the area off pretty close to the scratch and out another 10 inches with newspaper. Should the "scratch" be filled? Almost sounds like it...scratches usually can be taken out with wet 600 -1000 - polish... Over spray the gel coat with PVA so the gelcoat is cut off from the air and cures hard because you will need to sand with wet 280 400 600 1000 and polish; if that's where you're going. Same procedure for larger areas too.

PVA http://www.boatersland.com/fib105685...FZGiPAodxFwARA

These sprayers work real well too. http://shop.preval.com/collections/f...preval-val-pak

Gelcoat never lays out flat like a topcoat spray job. Sanding and polishing always required..

LOL