Re: Question about wet sanding
maybe its a wee late,But i would have started by buffing,Not sanding...
for a lot of reasons.for one sanding really takes a lot off the gel
a heavy duty rubbing compound is what I would use,almost all of the buffing machines are very light weight also,it could save you a lot of time and muscle ache,and the result could come out much nicer..If ever sanding I would start with 2000 grit.
I agree with you, but respectively only to a point. Generally speaking a person should always approach this kind of task using the least aggressive method that still gives the desired results. MOST of the time a good buffing with a quality compound and wool bonnet is sufficient. However, if the surface of the gelcoat is allowed to oxidize too far, no amount of buffing is going to bring it back. All you're going to get is a nice pattern of buffing marks (up and down, side to side where it's dark(er) with lighter squares in between these buffing lines). It may take a month after the buffing has been done to show up, but guaranteed they will. And by the following Spring, it will look the same as it did before (faded and chalky with little to no reflection)
In these situations the only way to bring it back to "new" is to wetsand. All wetsanding does is remove the top film (about 1 mil worst case, which really isn't that much) to expose a fresh surface that will buff out and polish up to look almost as good as when the boat was built. As far as grits, with gelcoat usually a person can go over the boat with 1200 with a DA or 1500 by hand and it will buff out great. Paint on the other hand is a different beast, nothing less than 2000 grit.
Now, all this being said, some boats inherently have thin gel when they were built. You'll be able to tell by looking closely at edges and radius's (the gel will appear a little speckled and lighter in color). Open flat areas should be thicker and OK to work a little harder. If you do wetsand, generally avoid corners and edges with the paper. Save those spots for the buffer
Hope this helps!
~BWT
