Hi I was sanding my foil today and it's scratched a lot but it's really smooth it just looks awful what can I do?

go up the different roughness paper till like 2000 with water. google it.

Maybe, next time tell Mr. Mittens he can't help you with the sanding? Even up to something like 800 will look better. Make sure there's no contamination on your sand paper like fine grit, sand, etc.

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Paducah said..
Maybe, next time tell Mr. Mittens he can't help you with the sanding? Even up to something like 800 will look better. Make sure there's no contamination on your sand paper like fine grit, sand, etc.

Remembered possible source of contamination - cheaper sand papers will shed grit if you get them wet, especially general purpose papers. True wet/dry oxide papers don't.

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Paducah said..

Paducah said..
Maybe, next time tell Mr. Mittens he can't help you with the sanding? Even up to something like 800 will look better. Make sure there's no contamination on your sand paper like fine grit, sand, etc.

Remembered possible source of contamination - cheaper sand papers will shed grit if you get them wet, especially general purpose papers. True wet/dry oxide papers don't.

Thanks guys I was using a cheaper sand paper the get the main coat off , then I sanded with 2000 but the rough sand paper scratched it, it doesn't perform bad it's performs better it's just looks lol. Thanks for you guys advice!

I wouldn't try to sand that out. I'd recoat it with a decent clear coat and start over. Sanding it out might start cutting into the carbon, which you don't want. Resurfacing it with clear coat will wet the scratches out and reduce the nasty look. I doubt it'll look 100% again, but it'll at least look better.


like the others said steer clear of cheap sand paper, and stick to finer grades. I wouldn't use anything harsher than 800 (and even that is probably a bit too rough).

edit: if you're looking to tidy up the whole mast, sand it all (still stick to a finer grade than 800) then clear coat the whole thing before sanding back to the finish you want. Avoid sanding bare carbon.

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Subsonic said..
I wouldn't try to sand that out. I'd recoat it with a decent clear coat and start over. Sanding it out might start cutting into the carbon, which you don't want. Resurfacing it with clear coat will wet the scratches out and reduce the nasty look. I doubt it'll look 100% again, but it'll at least look better.


like the others said steer clear of cheap sand paper, and stick to finer grades. I wouldn't use anything harsher than 800 (and even that is probably a bit too rough).

edit: if you're looking to tidy up the whole mast, sand it all (still stick to a finer grade than 800) then clear coat the whole thing before sanding back to the finish you want. Avoid sanding bare carbon.

Yeah my mast has a pretty thick coat on it so I can sand more?

It depends on what's missing of the original coat. Looking at your pic, it looks like the original coating is flaking off? If so, I'd be looking at sanding off the rest of the flakey coating, and lightly sand the exposed carbon then re clear coat the whole thing. Then sand to the finish you want.

Those are some pretty deep scratches. As an alternative to clearcoat, you might try a glazing putty like the one made by Bondo (www.3m.com/3M/en_US/p/d/b40067521/). Use some black epoxy-tinting to give you a black finish, and then spread it in a very thin layer smoothly over the involved area (you can just use the edge of a credit card). It cures in less than an hour and is very easy to sand. It's not strong enough for structural repair but that also means that it sands down before the hard epoxy of the mast, so you can get it really smooth without sanding into the carbon. Once it's cured, wet-sand with 400/600/1200. You'll have a very smooth, matte finish which you can clearcoat or not (I don't). The advantage of using this over a two-part epoxy filler is that it's so soft - fast to apply and it's much softer than the mast material so you won't sand into the structure.

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Awalkspoiled said..
Those are some pretty deep scratches. As an alternative to clearcoat, you might try a glazing putty like the one made by Bondo (www.3m.com/3M/en_US/p/d/b40067521/). Use some black epoxy-tinting to give you a black finish, and then spread it in a very thin layer smoothly over the involved area (you can just use the edge of a credit card). It cures in less than an hour and is very easy to sand. It's not strong enough for structural repair but that also means that it sands down before the hard epoxy of the mast, so you can get it really smooth without sanding into the carbon. Once it's cured, wet-sand with 400/600/1200. You'll have a very smooth, matte finish which you can clearcoat or not (I don't). The advantage of using this over a two-part epoxy filler is that it's so soft - fast to apply and it's much softer than the mast material so you won't sand into the structure.

My goal was to get the coat off, as all the patrik riders have told me to sand it off as it's quicker?

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RoyalontheFoil said..

Awalkspoiled said..
Those are some pretty deep scratches. As an alternative to clearcoat, you might try a glazing putty like the one made by Bondo (www.3m.com/3M/en_US/p/d/b40067521/). Use some black epoxy-tinting to give you a black finish, and then spread it in a very thin layer smoothly over the involved area (you can just use the edge of a credit card). It cures in less than an hour and is very easy to sand. It's not strong enough for structural repair but that also means that it sands down before the hard epoxy of the mast, so you can get it really smooth without sanding into the carbon. Once it's cured, wet-sand with 400/600/1200. You'll have a very smooth, matte finish which you can clearcoat or not (I don't). The advantage of using this over a two-part epoxy filler is that it's so soft - fast to apply and it's much softer than the mast material so you won't sand into the structure.

My goal was to get the coat off, as all the patrik riders have told me to sand it off as it's quicker?

The effect you refer to is very small, where it exists at all, and is absolutely trumped by the negative effect of even a small nick or bump in the surface big enough to disrupt laminar flow. You can test this by putting a smooth sticker or something on the windward side of your foilmast and noticing how much more readily it spins out.

I believe the idea behind a less-than-mirror finish - something like what you'd get with a smooth 1200 grit finish - is that a thin layer of water attaches to the surface and the water you're sailing through glides along over that layer, which offers less friction than the surface itself would. One advantage of the Bondo-type paste is that it won't hold a finish finer than about 2000 - too soft - so you'll never achieve a mirrorlike finish unless you finish up with clearcoat as you would in automotive applications.

Some manufacturers - SABfoil for instance, think that the clearcoat mirror finish offers enough advantages - for one thing you can really see any fault in the shaping - that the slight difference in slipperiness is offset. There comes and goes a fad in racing yachts for a micro-rib finish ("riblet") - about what you'd get with a really consistent 60-grit swoosh aligned with the flow - but mostly the big boats are very very smooth nowadays. The little ribs don't just trap water but also tiny air bubbles ("superhydrophobic" finish) and while the air bubbles are maintained the finish is incredibly slippery, but they just don't stay there that long before being swept away.

This showed up just today on the NW-Windtalk: