Cleaning mold from cloth sails

[Seasick]

I have a wooden ship model with cloth sails.  Over the years, the fabric has become very dusty and spotted with what looks like black mold.  I can remove the sails from the masts to clean them but what solution should I use to kill the mold without shrinking or damaging the fabric?

[Veszett Roka]

Try clean vinegar. Here we have a mold cleaner, but it contains chloride and it fades away all paint in no time but removes the black spots also very fast - so if your sails are white you can try bleach. Also you can ask a paint shop, they have a clean fluid addition for wall paints (sorry, don't remember the name) which kills germs, fungus and black mold. This fluid contains ammonium, but i never tried it on fabric. Be careful, i think better to try those liquids on a spare fabric, or a hidden spot of the sail.

[paul ron]

a weak bleach solution will kill and get rid of the mold stains. i had somethig similar with mold stains, bleach worked like a charm.

 

 

[Snug Harbor Johnny]

With vinegar or bleach, it has to be very dilute - especially with old material that may be weakened with age.  A better alternative is to order a product called "Restoration", meant to undo age yellowing or spotting on fabrics.  There are instruction, and I treated old sails as part of a Gorch Fock 1 restoration that can be found on MSW.  Easy does it is better than going whole hog of cleaning fabric.

 

[Seasick]

8 hours ago, Veszett Roka said:

Try clean vinegar. Here we have a mold cleaner, but it contains chloride and it fades away all paint in no time but removes the black spots also very fast - so if your sails are white you can try bleach. Also you can ask a paint shop, they have a clean fluid addition for wall paints (sorry, don't remember the name) which kills germs, fungus and black mold. This fluid contains ammonium, but i never tried it on fabric. Be careful, i think better to try those liquids on a spare fabric, or a hidden spot of the sail.

 

[Dr PR]

Bleach (sodium hypochlorite) is your best bet for killing the fungus - we used it in my medical mycology lab to kill the nasties. It was diluted about 1:3 with water.

 

However, what it will do to the old cloth is a question. Do you know what type of cloth was used? If it is silk you have few options. As was suggested above, whatever you use should be tested on a part of a sail that isn't especially noticeable.

 

On thing to remember about fungi (molds) is that they reproduce with spores. These are microscopic "seeds" that are made by the bazillions. Spores are really tough. The only way to kill some of them is steam sterilization (or a blowtorch). If you leave one alive it will eventually germinate and start the problem anew.

 

The fact that you have mold growing on the sails tells me that there is something in the sails that is fungus food. It could be the fibers of the cloth - depending upon the type of cloth. Or it might be some organic compound that was used to color the sails (tea) or perhaps starch that was added to give the sails shape. Starch is just polymerized sugar, and is readily digestible by a lot of critters.

 

After you remove the mold you should wash the sails to remove the mold food.