Builders' Forum Archives
Re: Sanding High Build Pr
Posted by Lance on May 12, 2004
I owned a boat building business a few years ago specializing in ocean going multihulls. We sanded "acres" of hull surface using the following method (and no, please don't recommend me to be "committed" to a mental hospital, this system works for a mirror smooth finish!!)
Get some quick dry lacquer spray paint in a contrasting color to the primer you used. Fogg a very light coat on the previously primed surface. You do not need total coverage, just a light "fog" will do. Get a standard wood paint stir stick and wrap an entire piece of 180 grit paper around it so the sandpaper forms somewhat of a "sheath" around the stick. Sand either dry or with water (depends on the type of sandpaper you use). As the paper wears down, tear off the two "used" surfaces, exposing two "new" surfaces. Continue using the sand paper in this fashion until you have used about half the paper then skip the tearing off process and rewrap the paper from the other end. This way you can use the entire sheet around the stick.
The purpose of the "fogging" of the spray paint is to act as a "guide coat" showing where you have sanded and where you haven't and the contrasting color shows even the smallest surface imperfections. Depending on how many imperfections and how perfect you want your finish you may apply more primer and sand with a finer grit the next time (we always went from 180, primer, 220, primer, 360, topcoat).
The last boat we did before a severe epoxy allergy forced me to shut the business down was a 45' catamaran and we sanded every square inch of the hulls with the above method (we did have wear cheap leather gloves as the sandpaper has a tendency to sand your finger prints off your fingers and this HURTS!!)
Hope that gives you some idea how to finish your boat
Lance Alldrin Chico,CA formerly "Ark Works"
In Response to: Sanding High Build Primer by Joe Lombardo on May 11, 2004