: Attn: Experienced S3 LPUsers. How much S3 LPU do I need to finish two 18 foot
: pygmy Kayaks? How many coats give the best presentation?

: Thanks

: Mike

Mike, I've only used it on one boat, but this is my experience. As for quanity I used 3 quarts to put 4 coats on a Guillemot fast double (26 ft long). Maybe a gallon would do ya'?
As others have noted brush marks are a problem with this finish. I've been meaning to post my experience with it anyway so I'll tag it on here. This is what I did and got pretty good results, but maybe someone else has better ideas. It was a lot more work than putting on varnish, but given how much work it was to sand out the brush marks I'm convinced that it is a much harder, and hopefully durable, finish that will be worth the effort. Even using a good brush and what I hope is good technique, the brush marks were quite prominent. I tried thinning the second coat to mitigate the brush marks but then I was having trouble with runs and decided to keep it thick and deal with the brush marks afterwards. I put on four good coats. I waited several days for the finish to harden then took it back outside to sand. I tried starting with 220 grit, but it hardly touched it. I wound up going clear down to 150 grit paper to get rid of the brush marks, then worked back up through the grits to 320 with a random orbital. It was then smooth, but obviously quite dull. Partly because I was tired of sanding, I decided to try wiping on a couple of quick coats to bring the sheen back. I thinned it out, roughly 2/3 finish to 1/3 water, and wiped on a couple of coats. For those of you who haven't wiped on a finish before, it's a wonderfully fast and foolproof method of application. It does, however, leave a very thin build. I used about 1 cup to put 2 coats on a 26 ft boat. At this point the finish was smooth, no rag marks, but the sheen was uneven. In retrospect, I think what I probably needed to do was to wipe on two or three more coats and that would have evened out the sheen with very little effort. At the time I decided that it wasn't going to work and that I needed to bite the bullet and rub the finish out. Since I was only going for a satin finish I optimistically thought that 1000 followed by 1200 grit wet sanding would do the trick. After that it still didn't have the sheen I wanted so I went back and got 1500 and 2000 grit paper. Pretty good, but still not there. Back to the autoparts store for some 3M Body Repair Rubbing Compound - Fine Cut. This stuff is designed to be used after 1500 grit paper so my 2000 grit step was probably wasted. At any rate this stuff worked. It's more of a gloss than the satin finish I started out to get but it looks nice.

I'm rigging the boat up now and hope to launch either next weekend or the weekend after- I'll post pictures then.
Mark