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Rust Stain Removal


Craig asked:

I hope you can recommend a product for a problem I am having.
I made the mistake of using steel wool to smooth wood trim between coats on a fiberglass sail boat. Now there are orange spots where the steel wool shards fell on the surface. How can I get the spots off?


For your convenience, I’ve highlighted the hyperlinks. Click on the hyperlink to get more information about the selected product.

It sounds like your problem is superficial, meaning that the stains are on the surface and not imbedded in the gelcoat. I will assume that your problem is on the deck.

The first product to try is Boat Scrub. Simply apply a small amount to a soft cloth and rub out the stain. If you have a lot of these marks, I recommend using a Marine Power Mitt with the Boat Scrub. It will save a lot of labor.

If the stains have been on there for a while and will not release completely, mix a 50/50 solution of Boat Clean Plus and Boat Scrub and work the stains out as above. These products will not harm your gelcoat and will act to restore the finish. This is what boat manufacturers use to remove yellowing and streaking.

If the stains still remain, this means that the gelcoat was not sealed and the steel filings have imbedded in the microscopic pores, rusted and stained. It will be necessary to dissolve the metal particles in order to get the stain out. Waterline Stain Remover will accomplish this but it is a strong acid based cleaner with deep penetrating surfactants and extreme caution must be used when working with this cleaner.

What you need to do is apply the Waterline Stain Remover to the stains with a cloth or brush and let it stand for 10 to 15 minutes and then rinse will to get it all off. You may have to repeat this process several times until the stains are removed. This is smelly stuff so be sure to work up wind. Protect yourself with rubber gloves, a respirator and face shield plus protective clothing so you don’t splash it on your skin. You also need to protect adjacent wood, metal, fabrics and paint etc. It is safe for gelcoat; protect everything else.

When you get the stains out you may have some super clean shiny spots on the deck. I recommend that you wash the rest of the deck with a 1:4 solution of Boat Clean Plus and water (use a deck brush on the non-skid areas and a Marine Power Mitt on the smooth parts). While still wet, apply some Boat Scrub and scrub well in all 6 directions and then rinse clean. Depending on the size of your boat, you may want to work in about 6 ft x 6 ft sections. Your gelcoat should be so clean at this point that it will literally fluoresce.

To seal the pores in the gelcoat so you don’t get deep staining in the future, and put an easy to care for shine on the deck, apply 2 coats of Sure Step. This will reduce dirt and stain attachment and make maintenance much easier (no more deck scrubbing). Sure Step is pressure sensitive so although it’s slippery and shiny, when you apply pressure, by stepping on it or pressing down on it, the pressure changes the co-efficient of friction and gives you grip. When the decks are wet, the traction increases even more.

Thanks for your question.

Your question and answer will be posed in the Ask the Skipper forum for the benefit of other sailors that may have the same problem. www.auroramarineclub.com

Captain Aurora

Richard Kittar

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