When I did the sanding, I figured that I was really getting thin on the gelcoat layer, so that is another reason I chose to rebuild the thickness for protection. However, if you want to just touch up some spots, the Preval works great. Just spray out the spots and then after cure, sand smooth and polish and you will not know it was there.
Lots of reading on THT about gel coat and lots of experts as well. For me, and my background painting auto/industrial for years including Imron's and Acyrlic Urethanes, I had a old Eclipse 78 spray gun that I used. I sprayed cars with same gun and it came out with excellent results and no orange peel, but the gun could also handle the heavy urethanes.
So I have been using it with the Gelcoat as well but using Duratec to help is spray better. At times, I have used Styrene to reduce it some, but not much.
In the end, you will get some orange peel affect depending upon spray method, reduction and how heavy you apply it. To get it smooth and pretty, you just sand progressively usually starting with 240, 320, 400, 600, 800, 1000, 1200, 1500, 2000 wet and then polish it. For the bottom, I skipped most of the grits. Started with 320, then I think 400, 800 and then polished it. But I keep getting areas that start to show the sand scratches and have to repolish it. I have been too lazy and haven't had the time to get out the air jitterbug and 2000 to resand and then polish. I just hit it again with heavy cut and it comes to life in seconds. Eventually, once per year if I keep hitting it like this, I might not have to do the 2000 wet. :mrgreen: But again, it is the bottom and it is smooth and nice! Much better than the old hard bottom paint that was chunky.
