anti mildew treatment

[MtHopeBay]

My mainsail cover that came with my good old boat smells like a hospital. A disinfected one. I've had it two seasons and it still smells that way, has not mildewed and is easy to clean. What is that treatment or material? I wish I had it in my sails. I just finished scrubbing my mainsail and I couldn't get all the mildew stains out.
Mike

[RichH]

Mike -
Most hospitals , etc. use a 'quatenary ammonia' compound for disinfection ... but you shouldnt be breathing it - dangerous!!!

For woven white dacron sails, the best for 'mildew' removal is to obtain a sodium silicate detergent (a product called Tuff-eNuff used to be carried by West Marine, so perhaps you can 'special order' it from them. Tuff-eNuff is manufactured by Wallace & Sons, Inc., St. Augustine, Florida ... do websearch and call them for a distributor in your area - expensive !!!!!)

Spray on the sodium silicate based detergent, lightly scrub to spread the detergent and immediately cover the sail with a plastic tarp to prevent dry-out. This product will dissolve the mildew cells ... so it takes 'soak time' to do the dissolving job. Remove the tarp and scrub with a long handled 'soft' brush applying additional detergent as necessary to 'keep wet'. Recover and let soak again. Rescrub/spray any remaining mildew. THOROUGHLY rinse ALL the detergent out of the fabric ... rinse several times until NO detergent remains.

Then, get some oxalic acid crystals (wood bleach) from paint or hardware store and mix into HOT water. You keep adding the crystals to the HOT water until no more crystals dissolve into the water (a saturated solution). A quart or two of Hot oxalic solution brushed on with a soft brush will be enough. Oxalic will almost instantly remove/bleach all the remaining tannin and iron staining (including the 'shadows' left by mildews that contained 'iron' in their cells). Then thoroughly rinse the sail several times to remove all the oxalic.
Caution - be SURE to wear gloves, eye protection, etc. when using oxalic acid. You do not want oxalic to come in contact with your skin - it quickly absorbs through the skin and deposits in the nephrons of your kidneys as 'sharp' crystals.

Hope this helps. ;-)

[sailingdog]

I would recommend using a full-face respirator mask along with heavy gloves when working with oxalic acid. The stuff can be very nasty.