I’m a spaz. I can never get away from not having to do a gloss coat. I get my laps as flat as possible, well as good as I get them, anyway. Then I do a perfect hot coat; I mean the thing sets up without any bubbles or glitches, but the occasional nat or June Bug as I do work in a hot, sweaty east coast garage. The hot coat dries and I sand. Inevitably I get some sand-throughs; I’m pretty sure my neighbors hear me cussing. So I do a gloss coat, which usually turns out really good.
The questions is: How superhuman do I need to be to only have to do the hot coat in a respectable manner? I hear it’s done regularly and I also hear bigfoot is roaming the woods.
Super Human = No sand or burn thrus. But you should still do at least a wipe-on finish. The wipe- on will hide slightly abused weave. If your getting burn thrus you should slow down the RPM’s but keep the sander moving. Use the sander on the flats. Hand sand the rails and do the final over all sand by hand. It’s nice to do everything that can be done with the sander. Not always possible though depending on the skill level.
Gunkie, I’m no pro, but I follow the lead of pros like McDing and here’s what works for me: (Epoxy; but I imagine the same applies for Poly):
Machine Grind fin boxes/leash plug with 60-80 grit on a hard pad (carefully). The 5" hard pad with velcro/backed paper from Harbor Freight does the trick. Cheap and easy.
Machine sand the deck and bottom with 100 Grit on yellow soft power pad. Resist all temptation to hit the rails with the 100. Hand-sand any stubborn shinies with 100 grit and all around after.
Machine sand the deck and bottom with 150 Grit on a super-soft Ferro pad. You are just taking out the 100 scratches here, not doing any heavy lifting. Hand sand 150 again just to make sure everything is nice. STILL DON’T TOUCH THE RAILS.
NOW I’ll hit the whole board and rails with 220 Grit on a super-soft Ferro pad. Nice and easy, slow RPMS, light touch on the rails. You’ll be surprised how well 220 works on rails with a machine. Once more: 220 by hand just to make sure the whole board is uniform.
Optional: Repeat step 4 but with 320 Grit.
Two coats; Behr low-lustre masonry sealer. Wiped on (like a hot coat) with a sponge. Watch for drips. As McDing says, this will seal/hide minor burn-throughs, but NOT major ones.
Burnish dried sealer with Scotch Brite Maroon (Very Fine); then Grey (Ultra Fine) on a soft velcro-backed Ferro pad.
I try to keep it simple. Industry standards generally are less not more. I have used cheater coats, piss coats etc. on lams and hotcoats, but after having been in some of the best glass shops on the West Coast and Hawaii and seen their process I came to the conclusion that such extra steps are to be used only to remedy a dry lam, a poor Hotcoat or over sanding etc. Lowel
I have ridden hotcoated boards since the early 70’s. A clean glass job with just the rail bumps sanded and you are good to go. I can make boards that shine like mirror with nice color etc etc but to me boards were disposable and I didn’t feel like waisting my time. Plus a good hotcoat unsanded is stronger than a board glossed and polished.
personally I like to stop sanding the hot coat at 80 grit, do a gloss coat, and who cares what the standard is? I don’t think of surfboard making as an industry anyway…although it is “hard work” so in that sense maybe.
Hi Barry, just to clarify, are you saying add the second layer after the first kicks, but before it sets hard? I’m consistently finding myself going back to redo spots around the laps and fin box/plugs after sanding, but I’d rather not if I could avoid it…
Gloss resin dries considerably harder than lam or hotcoat…surfboard resin is a 3 part lamination system …any deviation will have less strength , and is only a short cut to save labour cost and materials . If you don’t like the shine and polish on a gloss coat , just wet rub it.
Harder isn’t stronger. Harder tends to be more brittle…but harder. Strength is not found in finish coats of resin. Strength is in fiberglass cloth bound by resin
Although its easier to burn through, I still think that medium or hard pads for the flats is the way to go on the initial cut. Soft pads will ride any bumps you might have in your hotcoat. Soft and super soft on the rails/deep concaves.