Safe way to clean rust-like stains?

Aug 17, 2014
38
AMF SunFish & Puffer AL
I just bought a boat and the sails are in good shape but main has 1 rust like stain and jib has 2 of them.

From reading old posts I get the idea that anything that will work will be bad for the sails.

anyone found a safe way to do this or just live with them?

Thanks..
 
Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
I just bought a boat and the sails are in good shape but main has 1 rust like stain and jib has 2 of them.

From reading old posts I get the idea that anything that will work will be bad for the sails.

anyone found a safe way to do this or just live with them?

Thanks..
What I have used successfully to remove rust stains from sails is "The Works" which will set you back a whopping $1.00 at your local Dollar Tree store.

http://www.dollartree.com/The-Works-16-oz-Tub-Shower-Cleaner/p6065/index.pro

The oxalic acid in its formulation is what converts/removes rust stains.

I have never seen any evidence of damage to my dacron sail fabric (which is a plastic variation afterall). No evidence of adverse effect even many years on. Reference to damage to sails from solvents and cleaners might pertain to newer sails that still have their protective coatings on them. (This is just my opinion.) But many years on, probably not much of the coatings are still left to damage.

Depending on the severity of the stains, several applications will be needed. More of the stain will disappear after each application.

Going forward, you might want to determine what has caused the staining in the past. Most often, its that the sail comes in long-term contact with stainless steel fittings or riggings that have developed surface rust. Most on this site who have used it (including me) are very pleased with a product called Spotless Stainless that removes rust and the re-passivates the surface to slow down the rate of future rusting. Do a forum search for Spotless Stainless. You will see many before and after pictures. Great to use round a new old boat which most likely will have rust splotches on many SS fittings.

Back to "The Works": The stuff also does wonders to remove tannin and rust stains from gelcoat. Here is picture of it's effect on my hull under my transom overhang. The picture was after only one application. The second application re-stored the gelcoat to full white.

Note: Whoops -- after writing this, I decided to look at your profile (sail101e). Probably the Spotless Stainless info about not much use on your boats. Any, "The Works" should help out your sails. And rust/tannin stains you might have on your hull and deck.
 

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Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Re: Safe way to clean rust like stains?

yea, nobody really wants to tell you to put acid on your sails, and you probably cringe to think about it, but the modern sail material is actually a plastic formulation... and acid is stored for years in plastic without damage to the containers.

the paint on your boat or auto, the gelcoat, the fiberglass or epoxy... all plastic formulations.

rust on the other hand is organic, and acid will eat it.... and so is cotton thread, so providing your sails have been semi professionally sewn and assembled with polyester thread and not with cotton thread, a mild acid solution will clean the rust stains without damage to the sail themselves.
 
Mar 26, 2011
3,401
Corsair F-24 MK I Deale, MD
... but the modern sail material is actually a plastic formulation... and acid is stored for years in plastic without damage to the containers....

... rust on the other hand is organic, and acid will eat it, and so is cotton thread, so providing your sails have been semi professionally sewn and assembled with polyester thread and not with cotton thread, a mild acid solution will clean the rust stains without damage to the sail themselves.
Some good idea, but not in the details:

Working sails are polyester, which has good resistance to acids. Spinakars and some lines, on the other hand are nylon which is VERY vulnerable to acid. Drop some battery acid on a nylon rope and watch it melt away within minutes. Thus, weak acids are OK for polyester sails only. Yes, cotton is also vulnerable to acid, but you won't find that in sails.

Acid is stored in polyethylene containers. Certain other plastics are also used, but by NO STRETCH are all plastics acid resistance.

Rust is inorganic (not organic like cotton, nylon, and polyester), and like many metal oxides is soluable in weak acids.

Bleach will not remove rust stains; it functions by oxidizing, and rust is oxide. It can make the staining worse and will damage the sailcloth to some extent.
 
Aug 17, 2014
38
AMF SunFish & Puffer AL
What I have used successfully to remove rust stains from sails is "The Works" which will set you back a whopping $1.00 at your local Dollar Tree store.

http://www.dollartree.com/The-Works-16-oz-Tub-Shower-Cleaner/p6065/index.pro

The oxalic acid in its formulation is what converts/removes rust stains.

I have never seen any evidence of damage to my dacron sail fabric (which is a plastic variation afterall). No evidence of adverse effect even many years on. Reference to damage to sails from solvents and cleaners might pertain to newer sails that still have their protective coatings on them. (This is just my opinion.) But many years on, probably not much of the coatings are still left to damage.

Depending on the severity of the stains, several applications will be needed. More of the stain will disappear after each application.

Going forward, you might want to determine what has caused the staining in the past. Most often, its that the sail comes in long-term contact with stainless steel fittings or riggings that have developed surface rust. Most on this site who have used it (including me) are very pleased with a product called Spotless Stainless that removes rust and the re-passivates the surface to slow down the rate of future rusting. Do a forum search for Spotless Stainless. You will see many before and after pictures. Great to use round a new old boat which most likely will have rust splotches on many SS fittings.

Back to "The Works": The stuff also does wonders to remove tannin and rust stains from gelcoat. Here is picture of it's effect on my hull under my transom overhang. The picture was after only one application. The second application re-stored the gelcoat to full white.

Note: Whoops -- after writing this, I decided to look at your profile (sail101e). Probably the Spotless Stainless info about not much use on your boats. Any, "The Works" should help out your sails. And rust/tannin stains you might have on your hull and deck.
Thank you, about to head out the door to pick some up (The works). I am going to test on a very small area just to be on the safe side.

The puffer does have SS fittings, including an upgraded mast step. They all look great. What I do see that might be the source is on the sails themselves. Not sure of the proper terminology, but where you connect the halyard at the top (which is a SS connector) and the boom to the bottom are brass like metal in the sails. You can see some of that green corrosion . It's not bad on the main, but more noticeable on the jib connections. These are not SS so not sure how to deal with them. I am storing them inside the house , that should help some.

The Sunfish sail is not nearly in good of condition and feels kind of cheap in comparison. If I keep the boat I will just replace it. Thanks.
 
Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Some good idea, but not in the details:

Working sails are polyester, which has good resistance to acids. Spinakars and some lines, on the other hand are nylon which is VERY vulnerable to acid. Drop some battery acid on a nylon rope and watch it melt away within minutes. Thus, weak acids are OK for polyester sails only. Yes, cotton is also vulnerable to acid, but you won't find that in sails.

Acid is stored in polyethylene containers. Certain other plastics are also used, but by NO STRETCH are all plastics acid resistance.
Thinwater:

Thanks for the info. I'm not young any more but I do still appreciate to "read and learn".

I have also found that Spotless Stainless will remove rust stains from sails, which would make sense if the rust on the sail is a transfer of SS surface rust from a fitting. For example, stains are from a sail is flaked and stored over old boom bales. Or stainless steel clew or tack fittings have leached discoloration into the sail.

Spotless Stainless' active acid is citric. Would you think safer than oxalic if in doubt?

The main sail that came with my boat was severely stained with rust when I bought. Strangely mostly in the flaking-over-the-boom folds. Took me awhile to realize that the dry storage boat yard at which my boat was stored for two years was only 1/10 mile and downwind (and +20 mph was frequent) from a commercial steel vessel sand blasting and repainting company. Probably ferrous dust drafted over the yard on occasion and given enough time, settled in the folds. I became aware of what likely was happening when my new 2-part polyurethane paint job on the cabin top that I did in the dry storage yard before launching began to show lots of small rust spots all over soon after the job was finished. Other people in the yard had noticed the same thing but had not made the connection.

Anyway, oxalic acid did remove the rust stains from the probably 15 year-old sail. And the sail fabric and stitching remained intact for years afterward.
 
Mar 26, 2011
3,401
Corsair F-24 MK I Deale, MD
^^ About 2 years ago while working on a frac flowback recycling project in Pennsylvania I got to watch a 2000 gallon acid spill caused by a nylon hose fitting that somehow slipped in with the polyethylene fittings; they look nearly identical. It just melted. Fortunatly the operation was on a contained concrete slab, so no environmental concequence. But quickly telling plastics apart is often worse than telling SS alloys apart.

Boats are one of the most critical places to get all of the materials right. Sanitation hoses can look like water hose but arn't. Truck fuel hose is not marine fuel hose. The wire is different. Brass ins't bronze. And on and on.