I have an '99 Dagger Cypress. I want to paint it, probably primer, then a base color, then a tribal design over all of the area that’s out of the water. I know it’ll get scratched and such. My question is, what kind of primer will stick on a rotomold hull?
Nothing
Rotomolded plastic isn’t porous. Nothing will stick to/bond with it.
Painting Plastic
T painted an old late 70’s whitewater boat with the krylon spray paint mentioned above. He really didn’t expect it to hold up well, but it appears to be holding up fine. Where T has scrapped it over a few logs, the old color can be seen through, but the upper portions still looks great.
Really dressed the old girl up!
Deb
Just don’t
expect it to look like your car. 
A friend used a spray can to put shark teeth on an old school WW boat and it still gets a laugh.
Years before Krylon Fusion, I used
– Last Updated: Oct-22-07 6:39 PM EST –
regular Krylon spray paint to put some decorative flashes on the deck of a WW kayak, and to cover up the jackass Perception "Proline" logos.
I masked off the areas, sanded them with 220, and cleaned them with acetone.
The trick with spraypainting is to use several light coats, not one or two heavy ones. This avoids orange peel, and also results in a paint layer that is less inclined to pull off like a skin.
The decorative blazes are more than ten years old. They are nicked or scratched a little, but show no tendency to peel off.
I do not recommend painting large areas. The larger the area, the more potential for application mistakes, and the more weight gain. Decorative flashes should be the limit.
wel…
“Rotomolded plastic isn’t porous. Nothing will stick to/bond with it.”
I figured there’s got to be something out there that will stick to it, cause there’s the dagger logo, and the words “dagger”, and “cypress” on my boat. Those had to be put on there somehow.
they were put in the mold before
it was cooked…
baked
in the cake pan. literally. the graphics are stuck onto the inside of the mold before she goes in the oven.
the molecular make-up of the plastic is quite ‘oily’ and it’s very difficult to get anything to adhere properly, especially paint. even adhesive is ez to peel off.
steve
Krylon Fusion paint
The biggest problem people seem to be having with Fusion is a failure to read its’ directions!
Fusion is NOT to be applied over primer!
Shoot it directly onto the plastic surface.
I sail R/C sailboats, and this paint was discussed, praised, and dissed on those boards for the same reasons.
I painted a hull with it, let it sit for about two weeks (IIRC, it takes 7 days to reach maximum chip resistance) and it’s been just fine.
As for whatever mold release agent they use on rotomold, denatured alcohol is about the mildest thing I can think of that MAY remove enough of it to work for you. Acetone is pretty tough on a lot of plastics, but perhaps not RM Poly.
If the boat is more than a year old, and has seen use, I’d think that the mold release agent would be pretty much gone by now.
Auto paint shops sell a product called Prep Sol for use on surfaces before painting. Perhaps this would help.
Bob