Sandblasting

Greenflash35 · #1 (**permalink**) 01-17-2010

We're going to replace all of the interior hull paint " bilges, cabinets, etc" with Gel Coat. That's a lot of sanding, has anybody ever used a Sandblaster on the inside? Will 80 psi hurt the fiberglass hull?

bljones · #2 (**permalink**) 01-17-2010

wlanut shells would be a better choice than silica blasting, but I would hesitate to blast below deck. It gets everywhere, and you will be cleaning up dust for months to come. If you don't like sanding, you're going to have to strip it with a chemical stripper, and even then you will still have some sanding to do. In any event, are you sure you want to re- gelcoat? Paint would be a better choice, and will require less sanding.

Greenflash35 · #3 (**permalink**) 01-17-2010

Thanx bljones, we're not to worried about the mess because the sanding of the fiberglass is making a dust layer even with a vacuum sander. The reasons we would like Gel Coat instead of Paint is that on our boat there is heavy fiberglass cloth not mat and even with many coats of Paint it's vary porous and "difficult to clean". We would like a smooth surface. Also this sounds bad but part of the reason we're doing this is after we sail in Really Really bad storms the Bulk Head to Hull glass connection has cracked. So I'm going to beef it all up now but when we're out cruising id rather just slap a bandage over the Gel Coat.

sailingdog · #4 (**permalink**) 01-17-2010

You really don't want to use sandblasting on a GRP boat. It is too easy to damage the laminate with sand, since it is a very aggressive media. Instead of walnut shell media, I would recommend sodablasting the interior. Unlike walnut shells, the soda used in sodablasting cleans up with damp rags or towels quite well.

If you want a really smooth interior surface, you'll probably want to use a thin layer of thickened epoxy to both seal and smooth the interior surface. Gelcoat will stick to a properly prepped epoxy surface well enough for your cosmetic use. Also, the use of thickened epoxy on the interior of the boat will help seal the laminate and prevent water from migrating from a wet bilge into the laminate.