Removing Mildew/Mold From Sails

[Project_Mayhem]

I tried searching the forum and saw a huge variety of answers from dish soap to bleach! My furler wasn't working 100% last year and as a result it only unwound 95% of the way. Moisture got trapped and now there are black marks along the bolt rope. What are some tried and true methods that wont hurt the sail cloth?

PS - I'd love to hear some input from our resident chemist @thinwater

 

[rgranger]

I've had some luck using woolite and soaking the sail for a few days. I purchased a new 30 gal garbage can and soaked the sail in that. Then took the sail out and layed it out in the yard and scrubbed the remaining stains with a handheld brush. The mold stains were much improved but the rust stains were not improved by woolite.

 

[dlochner]

A non chlorine bleach will help. Try some oxy clean or maybe a little hydrogen peroxide.

 

[thinwater]

dlochner is on the right track. Sail makers universally recommend against chlorine bleach and in favor of oxygen bleaches. Chlorine damages polyester and kills laminates in minutes.

The long version is found in Practical Sailor (Feb 2018). If you are doing upholstery or really cleaning a sail, you need to read that and some other PS articles.

The short version is to scrub off the surface dirt with a warm borax/washing soda solution (soak fo a few minutes), and then was hthe sail with Oxiclean at standard laundry concentration for 3-6 hours. If you can get it in a tub, just keep wetting it for several hours.

If this does not remove all of the stain, just sail. The treatment "weakened" the remaining stain and the UV will finish it in a few days.

Rust stains are treated (not on nylon!) with a weak acid solution, such as CLR. Do not over concentrate.

 

[Project_Mayhem]

Thanks everyone for the simple and straightforward advice. I'll give it a try as soon as it's warm enough to dry out a sail!