Herb’s question is right-on. I’ve used minwax waterbased polycrylic on polyester resin and it turned out good, but I’ll never put it over epoxy again. Every time my board goes in cold water (which is everytime I surf) it gets cloudly white. It doesn’t sand off very well either. Maybe other brands are different, but it doesn’t seem to ever completely harden.
If you are just doing boards for yourself and you are not worried about seeing the weave from sand throughs, leave the filler ( hotcoat ) as a sanded finish, or if you are not worried about weight put a finish coat of resin on the board and sand this too about #400 or #600.
The board will be watertight and last twice as long.
Or you can use a product called seal skin which will leave a semi-gloss finish, it’s water based and you just wipe it on with a chux cloth or similar.
If you are down this way drop by and I’ll give you some.
I have been doing speed finishes on poly boards with what I mentioned earlier, and have bought stuff similar to future, but that doesn’t give a finish like a speed finish.
Only just starting to get into epoxy so was looking for something that will give a good speed finish on epoxy, and won’t burn down my garage.
FWIW, I’ve used Minnwax Helmsmann Spar Urethane (Home Depot) clear gloss on epoxy before. Leaves a very nice shiny coat. But I had some limited experience sanding the stuff I do remember it being ‘softer’ and clogging the paper.
Any advice there? I would think spraying it you wouldnt have to sand, but I like a sanded bottom, 400g.
I didnt spray it, I rolled and brushed it on.
Cheers
EDIT: I also remember the gloss coat being slick in the water…so duckdiving without wax on the rails was a problem.
It doesn’t have to be waterbased to use,but the waterbased stuff is much more user friendly. Plus the oil based PU seems to yellow quickly and yellow dark at that.
Howzit craftee, How long did you let it dry before sanding? I have found that even though instructions say the drying time is usually 24 hrs but it can take longer due to the environment. The spar varnish I use says 24 hrs but I let it dry for at least 48 hrs and then sand, makes a big difference.Aloha,Kokua