FSR

[Peter]

Davis markets a product called FSR , fiberglass stain remover, that works very well in removing stains of all kinds from gelcoat. I also discovered it removes those annoying rust streaks from 'stainless' steel.
All my blocks and stanchions are gleaming again :-)
How long will this last? Only time will tell.

[Rachel]

I can second that recommendation.

I used FSR on the bottom of my white-gelcoated dinghy after leaving it in the water a bit too long and getting a very stubborn brown-orange discoloration. After trying a few other things to no avail, I used FSR and literally hosed it all off in five minutes (no scrubbing).

I think it's a milder version of one of the acids (forget which one). One nice thing about it is that it's a gel so it hangs where you want it and doesn't tend to run where you don't want it. You "paint" it on, let it sit for (if I remember correctly) about ten minutes, then hose it off.

The directions say it's safe for home fiberglass showers and such, which makes me think it's not too caustic (although I was still careful about where the runoff went).

Rachel

[Maine Sail]

On & Off has a new gel formula that is a LOT less expensive and achieves the same results, just a little faster, because it's got more acid in it...

I like FSR but stopped using it when they came out with On & Off gel..

[Peter]

FSR contains Oxalic acid, also contained in spinach!
Acoustic: I'll check around for "On & Off Gel" as soon as my 2 liter jug of FSR runs out. Thanks for the tip!

[Tim]

I've always liked On & Off, but the liquid nature of it made it harder to use. The new gel formula sounds like a winner to me.

[Shark]

I'll second Peter's recommendation for FSR. The white gel coat on my boat was badly stained when I got the boat and FSR removed the stains.

I've never used it on any thing but gel coat but I think I've read that oxalic acid can also be used for removing black stains from teak. Anyone here had experience with that use?

[Tim]

Oxalic acid is a common product used to bleach wood, including teak.

[David VanDenburgh]

I've never used it on any thing but gel coat but I think I've read that oxalic acid can also be used for removing black stains from teak. Anyone here had experience with that use?

We've used Bar Keeper's Friend, which uses oxalic acid as its prime ingredient, to clean up teak. It's milder than mixing up a batch of oxalic, but it works fairly well, sometimes requiring two or three applications to lighten the wood sufficiently.

Te-Ka is a pretty impressive product for cleaning teak, and it's recommended by Rebecca Wittman, a varnish guru (among many other things). It does a fantastic job of cleaning with minimal effort. Te-Ka is not for fiberglass and must be neutralized and rinsed thoroughly.

David