rockcitycafe said:that part is from a brand new mold, so the surface is really high gloss, I'd hit it with some 400 grit just to make sure the paint has a good surface to grab, I don't recommend shooting paint straight onto gelcoat, I've always felt that a good primer will eat a bit at the gelcoat and provide a really nice surface for the paint
axeugene27 said:see sometimes you can directly talk to the manufacturer and get good answers. One of the benifits of buying small company american made stuff.
Booligan said:BTW, how do you like the Bonneville seat? I was looking at it for my CB175 buildup, but wasn't sure about the width of the flat portion of the seat. The 175 has a funky spot where I would be mounting it up, and the width of the flat mounting area is important. Looks like their site says that it's 7.5" wide, but with the sloped sides of the seating area, I'm not sure what I'd be working with.
Red Devil said:The gelcoat does not need to be primed unless you have flaws to bodywork or else break through to the glass underneath. Sand with 400 grit paper if you are planning on painting it a solid color, if you are planning to paint it a metallic I would usually go to 600 grit.
mathil said:I see this thread got raised from the dead, but for future reference...
Fiberglass molds have intentional contaminants added to their surface. These come in the form of waxes, mold releases and PVA. All of these things are anathema to a good paint job.
It is possible to paint basecoat directly on gelcoat. I've done it probably 100 times, but first you need to be absolutely sure all the release products are off of it. You need to remove these before sanding, or you'll only succeed in sanding them into the surface. Basecoats are sensitive to such contaminants and will puddle, or fisheye, or generate other flaws if you're lazy on the prep.
Before you sand it wash it with TSP, wax and grease remover, soapy water, acetone and rubbing alcohol. It sounds excessive, but you have to use a solvent that can remove the mold release. Basically, wash it with everything in your arsenal before you paint.
Sanding to 400 grit is sufficient for a basecoat. Make sure you sand until there is absolutely no shine left on the part in any small patches. I prefer to sand to 400, spray sealer and then spray base wet on that. The reason is if you have a white gelcoat seat and you're painting it red you'd have to put an excessive amount of basecoat on it to achieve hiding, as opposed to a black sealer. Every basecoat color has an ideal substrate color of black, gray or white. Metallic red over white has been the hardest to achieve hiding in my experience.
High On Octane said:Your best and most cost effective solution is to use a 2K urethane primer. It will have excellent adhesion to many surfaces including bare metal, plastic and fiberglass. I like to mix my 2K primer 4:1:2 and use as I sealer too, it works very well. If all of your body work is done and your surface is sanded to 320 grit or finer, just use the 2K as 4:1:2 sealer, 2 coats waiting 10-15 minutes in between coats (or until completely flashed off) and wait about 20 minutes and you can top coat with the urethane enamel right on top.
Scottie J