You are trying for a "mechanical" bond. If you shoot multiple layers of gel coat, you want to do it before the first layer flashes off so that a chemical bond is achieved for the those layers.
This is true if your using Duratec. Treat it like paint. However, If your shooting gel coat without wax or Duratec you can let each coat kick before the next coat and still have a chemical bond. Gel coat without the additives stays sticky after curing.
Yeah, man. Hotcoat! Spray a good heavy coat of gel, don't make it sag though. Walk away for a bit to let it go off a little, and toss the gun in a cool place... we use a small fridge... then come back and spray a little more. Repeat several times. You've got to watch the thickness though to avoid runs.
I know a guy that walks away from the first coat and takes the opportunity to leisurely grind up his weed. Then he goes back to spray. The second break he rolls a spliff, and goes back to spray a little more. The third break he smokes it, and goes in for his final application. Says it helps him avoid the peel, which lessens his finish time.
I usually take old gel down to 120 before spraying. Fix any and all pinholes ahead of time to avoid pin air. Don't use any epoxy fillers. Marinetex should be banished from the cat sailor's lexicon...hate that shite. It's ruined more gel repairs than any other substance known to man. Formula 27 works well.
