Rust on Our Fiberglass Hull !

[ggeardino]

Well we went on our first long trip and dumb me, I put canned soup in the storage area near the bilge pump. So long story short, the cans got wet and the rusty water came out of the boat through the bilge and rusted the side of the boat! Does anyone have an opinion on what is the best product to remove it? Thanks!

[SeaBungalow]

We've had good luck with Bar Keeper's Friend on removing all kinds of stains from fiberglass decks. Non-abrasive cleaner.

[Sailmonkey]

or try wichinox by wichard. just remember to wax after cleaning the rust off.

[roverhi]

If you can find oxalic acid in small quantities buy it. Hell, if you can find it in large quantities, buy it and sell the excess to your friends. Oxalic acid is the active incredient in Barkeeper's Friend and probably all the other rust stain removers. It comes in a crystal form, just mix with water and paint on the stain, wash off after a few minutes and stain will usually be gone. Persistant stains may take several applications. We used it on our Westsail 32 to do away with the topside stains from the exterior chanplates that afflict all boats with these. No rubbing, buffing or elbow grease, just paint it on and rinse away the stain.

It's also a good wood bleach. Suspect it's the active ingredient in teak cleaners.

[AnchorageGuy]

you don't say where you are. If you are in the US, go to Home Depot and get a product called RustAid. The stuff is magic.

[GordMay]

RustAid is another, in a long line of products, based upon Oxalic Acid.

[AnchorageGuy]

Yep, But it is very inexpensive.

[cdennyb]

YEP, certainly not THAT expensive.

Real Milk Paint ® - Oxalic Acid Wood Bleach

These guys say it doesn't work and it's too toxic.
make your own decisions.

http://www.ecomade.com/ainfo.php/lid/17/products_id/28

[delmarrey]

Nitric acid, it eats iron/rust but not plastic!

Eye and hand protection required, your body has iron.

[forsailbyowner]

Another brand we use is whink, look for it in a brown plastic bottle in cleaners section of grocery or big box stores.

[Sunspot Baby]

We use wood bleach and it DOES work. Just remember to rinse well after use or it will leave its own stain. Available at many hardware stores but not all.

Wear glove if you are going to scrub while using it.

George

[GordMay]

Originally Posted by cdennyb

... These guys say it doesn't work and it's too toxic. make your own decisions...

“These guys” are Singerman Laboratories who sell their own products. The linked site compares their own product with those of other manufacturers. Hardly a creditable opinion, on it’s own.

[David M]

Be careful with any acid, the lower the pH, the more likely it is to discolor the gel coat. This is especially true the darker your gelcoat.

Start with the most mild acids first, like vinegar, and then apply them over a greater and greater time period so as to minimize the chance of damaging the pigment in the gel coat. Then step up to the next level of acidic compounds, (lower pH) if necessary.

Keeping relatively porous gelcoat filled in with wax, silicone, teflon or other substances that come in gelcoat polishes will help prevent stains in the first place.