Stubborn Salt stains on hull.....anyone !!!

[yohoho]

I have just returned from a 6 month trip and have bad salt staining on my hull. As the hull colour is Blue this really shows up. I have tried fresh water, soapy water, water with chemicals for removing most other stains but nothing works. It's like a really hard speckled crust, a bit like orange peel effect you get on badly painted cars.

Does anyone know of something that will get this off ???

[Tempest]

FSR in the Blue container works on my White Hull....for tough stains.

I would test a small spot on a dark hull..I'd hate to see it take more than the stain off..

Here's west marines selections

Fiberglass Cleaners Maintenance

Tempest

[SVlagniappe]

Davis FSR is the bomb! I've only used it on white Gelcoat however...

[14432]

Could it be something other than salt? Seems like if soap & water will not work - especially hot water - then this is something other than salt.

FSR is great for waterline-type stains, rust, etc. but what you're describing seems to be something else.

Where is this stuff - all over the topsides, at the waterline?

[KeelHaulin]

Salt deposits can usually be broken free with an acid wash. Try white vinegar first and see if it has any effect. You can mix a 1/4 cup of muriatic acid (swimming pool acid) in with a gallon of water for a stronger acid solution. Of course you will want to test this on a small area before you do the entire boat. Gelcoat is usually unaffected by acids; and I'm pretty sure FSR is a gelled acid.

[georgefmys]

Try Salt-Away sold at West Marine,don't know what's in it but I have used with excellent results. Seems able to break down even very stubborn salt deposits. As you may have already found out, standard cleaners and stain removers don't work on encrusted salt.

[yohoho]

Thanks for all the help people - it is definately salt, there is nothing else it can be unless someone sneaked up while I was at anchor and sprayed something on every square inch of the hull !!
Until this happened to me I would never have believed just how stubborn this stuff is, it's crazy.
I'll give some of your suggestions a try but here in Australia some of these branded products could be hard to find. I was hoping someone would come back with something simple like 1 part lemon juice, 2 parts tabasco sauce and a drop of rum. I'll start with the vinegar !

[Ogrenaut]

Cut a lemon in half and sprinkle liberally with table salt. Gently rub this on the affected area. This took out old rust stains on my sails and I would suspect it would take salt stains off your hull. I would caution about the abrasive property of any undissolved salt crystals scratching you paint/gel coat.

The down side to this is it takes a lot of lemons. Vinegar and a mild abrasive, like Bon Ami®, might be a good, cheap solution.

Good luck.

[Tempest]

We used to make a paste of Lemon juice, flour and kosher salt to clean copper pots...the salt was there for abrasion...you might eliminate it.
just try the lemon juice and flour...

Save the rum for drinking!

[GaryHLucas]

Salts are removed by acids. I wouldn't go with muriatic acid (weak hydrochloric) as it is a very corrosive acid. The lemon juice is citric acid, which you can buy powdered. Vinegar is Acetic acid. Phosphoric acid is better though, you'l find that in a product called On & Off or something like that.

Oils and greases are removed with caustic cleaners. Easy Off oven cleaner is Sodium Hydroxide. It often helps to alternate chemistries as fouling can be in layers of different kinds.

Gary H. Lucas