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Not sure what caused it but I have a reddish brown stain on the hull that I would like to clean off. I'm not the only boat in the yard in the issue so definitely something in the water and not just age. ImageUploadedByTapatalk1417999154.761668.jpg ImageUploadedByTapatalk1417999171.561227.jpg

Any ideas on how to remove? Topsides are circa 1985 gelcoat.

In same vein, could use recommendations for cleaner/wax, the 3M stuff did not do well on last attempt.

Josh
 

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We use a product found at most hardware stores or Home Depot made by Goof-Off. It's just called Rust Remover. Spray or wipe it on, watch the stain disappear and rinse thoroughly. We use it all the time to get the stains off the hull while running the river systems and some parts of the ICW. Chuck
 

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Oxalic acid in all its different guises, as crystals from Home Depot. FSR from West Marine, and Barkeepers Friend from any grocery store, (my favourite). Or hull cleaner from Walmart (Attwood hull cleaner).
+1 For oxolic acid. Cheap, wipe on-wipe off effective and is probably the base ingredient for a lot of $$$ specialty products. Just keep it away from galvanising.
 

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cheaper than bleach? jajaja
Purchased as oxalic acid crystals is cheap enough to count the difference in pennies. Oxalic acid is also known as "wood bleach". I used to use it to clean my hobie 16's waterline after it had been sitting in muddy water for a few days and nothing comes close to how well it does the job imo. The odd thing is oxalic acid is recommended for removing rust stains and I have to say I've really never had what I would call good results with it when used for that purpose.
 

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bleach cleaned my teak pretty damn well too!
good to know...next time ill use oxalic acid

in any case 2 galons cleaned my whole hull

how much does oxalic acid cost at the dollar store?
 

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I brought a 500 g container about 10 years ago and still have plenty left. You don't add much to (warm) water to get an effective strength. I think it was about 10 bucks or so at the time. That's in AU dollars and we seem to pay double of what everyone else does :(

No idea what it's worth now but it's not expensive. Just cant get it in lemon scent ;)
 

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The brown stain occurs because the gelcoat has become more porous as it ages. You want to be careful about making it more porous and make sure you seal it well.

We used MEK to clean, then a light compound. Then seal the hull with Scotchguard in the black bottle. I'd be afraid of damaging the gelcoat with too harsh chemicals.

The stain has not returned in 3 years even though we have not hauled the boat to reapply the polish (we plan to do that this Spring.)

Tod
 

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The best cleaner I've found in more than 50 years is LA Absolutely Awesome Cleaner, available at Dollar General and Dollar stores for $1 a bottle. Spray on, wait 2 minutes, wipe off, rinse with clear freshwater. It's what the name says - Absolutely awesome.

Gary :cool:
 

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All the 'acidic' remedies mentioned will work to clean the hull.

The 'reason' that this staining occurred is that the gelcoat in that area has become 'porous' due to oxidation and microscopic surface cracking of the gel.
The Remedy for that and to help prevent 'boat moustache' is to 'vigorously compound the hull' to remove the old dead surface gel, and then 'push'/force wax, etc. into the remaining porosity.
.... dont just smear the wax on and then wipe off; PUSH it into the porous gel and leave some polished wax on the surface to build up that 'seal'.

You can websearch most 'boat forums' for Mainsail's most excellent offering of 'buffing and waxing' ... and then if you dont want the 'moustache' to return, youve got to wax and buff seasonally to keep that 'porosity' sealed.
Start your search here: http://www.sailnet.com/forums/gear-maintenance/52772-tips-compound-polish-wax.html
 

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Try toilet bowl cleaner on a small spot. It worked when i kept our boat in the Indian River down in Florida.
 

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We have the same condition , and although I wouldn't disagree with anything said here I like to spray on straight bleach . First I wet the area with fresh water, spray the bleach wait about 2min . then hose off . A good soap down after doesn't hurt . I can do the whole boat in about a half hour . In our marina we have these rubber rub rails in the slip , they are nasty , touch one with your hull and you get a black stripe . The only thing that completely gets it off is Mr. Cleans Magic Eraser .
 

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Is it safe for the water? you know, environmentally and all that.
I looked into that a little bit and it looks like oxalic acid is safe. It occurs naturally in a lot of plants and breaks down fairly quickly once in water.

The sailing club I'm in uses Barkeeper's Friend (oxalic acid, soap, and an abrasive) to clean our MC scows and after the first time I saw how much of it was ending up in the lake I had to go home and look the stuff up. Turns out it's OK.
 
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