Jet Ski Paint Prep

[brapperdoodle]

So Ive just finished my fiberglass work and Im ready to prep my ski for paint. I have sanded a decent amount on the bottom of the ski and filled all of the scratches that I care to. My question is, do I need to remove all of the factory coating? Not sure if this is "Gel Coat" because people argue too much in threads... The underside of the ski is part raw fiberglass and part factory coating (where I didn't sand deeply) The underside of this 1995 Yamaha was hideous to begin with, and now looks smooth and ready. As for the top deck, does that need to be sanded beyond the factory coating? Im planning on doing a proper paint job in an actual paint booth. My brother is actually spraying it but I need to get my boat prepped. I will probably be using House of Kolor paints... What do you recommend for paint prep?

 

[mikidymac]

You need to sand the entire surface with something like 400 grit. You don’t need to remove all of the factory paint but you need to scuff it up really good so the new paint sticks.

On the superjet the bottom is painted but the top deck is gelcoat. The big problem spot is the factory hood as Yamaha didn’t prep them correctly and the paint peels off. The hood is the only part you need to remove all the factory paint all the way down to raw fiberglass or it will continue to flake off even with new paint.

Your base coat should be a good epoxy primer.


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[schicks]

Best to sand with 180 grit leaving factory gel coat, spray a high build primer to seal all the body work, sand primer with 320, then paint.

 

[chadly]

Depends what paint you use, You will see those 320 scratches.

 

[schicks]

That can happen when you dont fully sand the 180 surface to 320. To prevent this, you can add ink to acetone and wipe it on the surface, basically giving you a color guide to sand off so you know didnt miss any spots. You can also use graphite powder. High build primers will change color tone when you sand, which also acts as a non cheat guide if you pay attention. Im not familiar with house of color paint, but ive never had 320 scratch marks show with awlgrip paint.

 

[brapperdoodle]

I went to the local auto paint supply shop and got my paint and such ordered. I asked then about flex additive for the clear coat, and they told me it wouldn’t hurt anything but also said it wasn’t necessary for my application. It’s about $80 extra and I don’t mind spending that if it makes a difference but the guys there really seemed to think I didn’t need it. They pretty much said it’s only for stuff that is really gonna be flexed like thin plastic and stuff. What do you all think of a flex additive for the clear?

 

[mikidymac]

It's really not needed. All of the new polyurethane clears out will flex enough for a ski. It's more for the soft plastic bumpers that really flex.

 

[brapperdoodle]

It's really not needed. All of the new polyurethane clears out will flex enough for a ski. It's more for the soft plastic bumpers that really flex.

That’s pretty much word for word what they were saying

 

[mikidymac]

Just follow the advise of the paint shop. They are usually pretty knowledgeable. The main thing is prep and keep the hull super clean. Then make sure you follow the paint instructions for temperatures and flash times.