I have a fibergl*** cobra body I'm going getting ready for painting. It has a red gell coat on it that has a gloss finish. Can I scuff the gell coat with a red scuff pad, primer it and paint? I need to know what sand paper you are using on the primer to. Thanks for your help
I would use the gell cote for block sanding it with everything from 120 grit to 330 grit as needed. You can do any filler work, remove all seams etc before priming.
Yes but make sure you do not go through the gel coat - if you do you'll have gel coat it again! Personally I'd use wet & dry 600 grit (you're only trying to key it, not blocking for straightness I take it). Ask you paint suppliers which product us best used on fibergl*** and pay close attention to thinner amounts as anything which contains lots of thinner may result in going into the gel coat (=sinkage).
I would start with 320 wet, lay on some epoxy, then primer before the 'no sand window' expires. Let both cure well and start blocking with the same grit. Once flat, another light primer coat and 600 before painting. But, it may take (more likely, will take) more than one primer application.
@birdman1 You can block that gel coat Depending on how old the body is, some gl*** body manufacturers recommend scuff sanding the gel coat and allow it to gas out. Anytime you refinish something, the product tech sheet will tell you how to prep the part. Meaning, you look up the primer/paint and prep the body according to the product manufacturer’s recommendations. My rule of thumb is most regular primer surfacers will bond to 320. Primer -fillers or high build surfacers are thicker and would need something courser than 320 Again, the product tech sheet will tell you. If painting directly over the gel coat, prep the body according to the paint tech sheet recommendations. I’d at least seal it. To look up a tech sheet simply google the product name/number. For instance you can get the tech sheet for JP202 that way https://www.craggyaero.com/Ventus/SL202+JP202+2K+High+Build+Primer+Surfacer+03+15-2.pdf you get the mixing ratio, surface prep, how to apply it over different substrates, flash times ……. Don’t trust the generic answers given by the paint store guy or us random internet experts
The first thing you need to do is use a wax and grease remover and get every bit of release agent off the body… Go over it two or three times…
Agreeing with @oldiron 440 to remove the stuff on the surface and with @anthony myrick to select all your supplies first and do what they tell you for each step. Just like building an engine, have the build planned before buying the parts. As for blocking, the way it was explained to me was like road work. You bring in the heavy s****ers to get the contours right first (heavy grit sandpaper), then progress to finer and finer grade machines (higher number sandpaper) to get it smooth prior to laying down the road bed. If you start with fine stuff, it will smooth up and over the big rocks and leave the hollows, not get things really flat, if that makes sense. If you haven't done it before, you may not have the 'feel' to judge how much blocking the body needs. Try putting a paper towel between your hand and the surface and rub lightly. It may help you feel the highs and lows. Since it sounds like the body is still shiny, you can look it over with a bright light and a lined board, too. They are used for PDR or you could cobble up your own. Most kits have dedicated forums with people that have been there before. It helps to read up and find out if everything fits before starting body work. One kit from a well-known place has a known issue with the (not a cobra) p***enger side door fit which requires cutting the inner from the outer and repositioning so it matches up on the outside and fits the opening on the inside. Better to do the big stuff before worrying about the final finish! I remember reading one guy's build on a Cobra. He got it built, carefully following all written instructions and the guidance of others. Found out he had to remove a rear suspension part, but the bolt was put in front to back then the aluminum inner installed that blocked the bolt's removal! Had to drill a hole in the inner or cut the bolt off a little at a time until it was all out, then install it back to front.
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