I have my hull striped down and ready to be sanded but wanted to know if you have to sand it down to the fiberglass before painting? Also what is the best paint to use.
1.. sand down to fiberglass... no...
2.. best paint to use... gel coat...
1.. this will differ depending on substrate(what's already there).. if it hasn't been painted before(factory gel) sand with 400-600 until the shine is all gone..
if it's been painted before, could be a different story.. painted once i would go with the previous procedure.. if there's more than one repaint, sand to gel coat
or close to it using 180 followed by 320 then prime with something(depending on the system you want to use...
2.. gel is the best to use, though not the most feasible.. rattle can paint will work if you're on a low budget project and just want to to look decent(i'd suggest one of them trigger deals or your finger will be sore).. automotive paint system(weather it be ppg, dupont, hoc, sherwin williams, basf) is virtually the "best" next to gel... if sanded with 320 for primer, i would NOT use a high build primer(they are NOT a moisture barrier, and would be much like using body filler) epoxy primer sucks to sand but does have filling characteristics.. if the substrate does need filing your only real option is high build primer.. if this is the case so be it, the only alternative is extensive and would require more product and procedure than i want to get into... if the substrate is more or less defect free(at least to your taste, and you started sanding with 180) epoxy then paint(paint will not fill 180 or 320 grit but epoxy will).. if epoxy primer is used, let epoxy flash for 2-4 hours then paint(no sanding if done this way, if you wait until tomorrow you will need to sand it)...
if you just sanded with 400 or 600 you don't need to prime it with anything, just sand and paint(weather you're doing single stage or base clear)...
the key to any paint job is prep(doesn't matter what paint you use) before you even start to sand clean it with a mild detergent and water(much like you'd wash your car) but not that "wash n wax" crap... after that, clean it with a good wax and grease remover(any auto paint store) keep wiping until it's mostly dry... now sand it... after you're done sanding(before you paint) wax and grease one more time... let dry good before either paint or primer...
*if you don't use auto paint, then skip all of it and just do the prep part...
if i didn't know any better i'd say i've painted a time or two...