So I’m building a board for a friend and he wanted a deep blue bottom wrap to rail bans on the deck. I’m building with 2 pound EPS. So I finish the shape, spackle lightly, give it a light white airbrush (tempura + acrylic, 50/50). after drying, I hit the white with a light scrubby pad then I mask and paint the bottom and rails in a deep blue (blue tempera + acrylic, 50/50). After that dries I hit it with a light acrylic coat. The board surface now feels strangly smooth and tight. I’m used to a bit of fuzz on the surface that I knock down with a light scrubby pad.
I’m willing to scrub the board down a paint again, if needed. The other boards I’m building have that fuzz which I am used to.
My question is: When is an airbrush on foam too thick and might cause a delam?
Doesn’t sound like you over did it to me. But I don’t see the reason for the Acrylic. So if you have a problem it won’t be due to the paint but rather the Acrylic.
Too much heavy paint on any foam has the potential for delam. But it sounds as though you went about the spackle and paint in the correct fashion. I don’t see the need to seal paint with acrylic sealer. Epoxy is less likely to react with paint. If you used an acrylic paint there would be no need to seal. The sealer stays hard and slick on a painted surface. I don’t think you have anything to worry about. Lowel
I once had a strange reaction when glassing over blue paint…aqnd only over the blue. The resin crystalized in spots over the blue. Thankfully there wasn’t a lot of blue on the board and the spots I had to carefully grind and re-glass were minimal. I’ve avoided dark blue since.
Not related to delam, but glassing with epoxy over dark blue there is a tendency for the weave to show and look “milky”. Not a problem with lighter colors, but definitely with dark blue. I also avoid dark blue, since I glass with epoxy.