• Untitled Document

    Join us on March 29rd, 7pm EST

    for the CBEC Virtual Meeting

    All EYO members and followers are welcome to join the fun and get to know the guest speaker!

    See the link below for login credentials and join us!

    March Meeting Info

    (dismiss this notice by hitting 'X', upper right)

Cleaning green mildew crud from canvas

KS Dave

Dastardly Villain
Blogs Author
Greetings fellow lake-sailors. While I was pleasantly surprised at the state of my genoa when I unfurled it for the first time (it seems to be in great shape), there is a fair amount of the green mildew-y crud on the Sunbrella cover. I've had limited success scrubbing this stuff off with soap and water (using a stiff brush). Anyone have a silver bullet for it?
Maybe this isn't only a freshwater problem, but I don't have any experience with boats on saltwater. This same stuff seems to grow on everything around the lake.

GenoaCrud.jpg
 

markvone

Sustaining Member
I use this process from the Sunbrella website. I lay my canvas on a glass top patio table in the shade to soak in the cleaning mixture if there is a lot of mildew/crud. I scrub with a clean, firm brush dedicated to canvas cleaning. I would consider soaking in a bucket/bathtub (total immersion) if really dirty. Freshwater rinse/soak to reduce bleach smell.
After clean and dry, recoat with 303 Protectant to re-waterproof. Keeping the canvas waterproof to the maximum extent possible will really help keep the dirt and mildew at bay.

Mark
 

Attachments

  • care-and-cleaning-tips-sunbrella-marine-tops-covers-en-us.pdf
    407.9 KB · Views: 3
  • IMG_0451.jpg
    IMG_0451.jpg
    18.9 KB · Views: 5

KS Dave

Dastardly Villain
Blogs Author
I use this process from the Sunbrella website. I lay my canvas on a glass top patio table in the shade to soak in the cleaning mixture if there is a lot of mildew/crud. I scrub with a clean, firm brush dedicated to canvas cleaning. I would consider soaking in a bucket/bathtub (total immersion) if really dirty. Freshwater rinse/soak to reduce bleach smell.
After clean and dry, recoat with 303 Protectant to re-waterproof. Keeping the canvas waterproof to the maximum extent possible will really help keep the dirt and mildew at bay.

Mark
Thanks, Mark. Bleach was on the list of things if Simple Green didn't work. This is a genoa, so I'll be laying it out on my driveway to scrub on it. Why in the shade?

At that dilution strength, the bleach didn't discolor your fabric?
 

markvone

Sustaining Member
I would be careful laying the sail (or canvas) out on any hard surface due to wear from abrasion and adding stains from oils, etc. I would use the lawn first but you can get dirt stains. The beauty of the glass top patio table is that it's flat and smooth but clean. You could do a sail one table-sized section at a time. I do it in the shade to maximize the soak time (prior to the scrub) as the cleaning solution will dry fast in the sun and even faster in low humidity (not a problem here). I have brand new light tan Sunbrella canvas and old black Sunbrella canvas and no sign of fading with the cleaner. Those instructions do come direct from Sunbrella.

Also, you can have the genoa sun cover replaced by any sailmaker. It's sewn on last for that very reason and it's common to need replacement when it's torn, worn or faded.

Mark
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
MIldew stains are very hard to get out of Dacron, and since mildew grows on dirt, we're advised to keep the sails and covers clean. Easier said than done.

I take my Sunbrella sailcover home every year and work it over with detergent and bleach (Sunbrella is impervious to bleach)-- and never get a spectacular result. Actually, I lay off the detergent, because that means waterproofing again--a big job for a sailcover.

I use my concrete driveway to wash sails, after sweeping it, vacuuming with shop vac, and then hosing it down with detergent. The result of scrubbing with a push-broom is as good as "professional" sail cleaning, which (to me at least) is not worth the money. And mildew stains don't come out.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
A guy I hired to redo my sail cover said they clean canvas tops with a pressure washer. Don't over-do it on the pressure/tip width, obviously.
 

Drewm3i

Member II
I gently pressure clean all canvas with an electric power washer. It works wonders, but you have to be careful. I dont have the patience for scrubbing, which can also damage the fabric.
 

bigd14

Contributing Partner
Blogs Author
I just cleaned the green algae off my cover with a pressure washer. Results were mixed. The cover is navy blue so as soon as it got wet I could not easily see where I had sprayed. When it dried it became obvious. It’s better than it was. I have not determined if the waterproofing has been entirely blasted off yet. Not sure what I will use to waterproof it, the options I have seen involve some nasty chemicals. No obvious damage from the pressure washer (electric).
 

paul culver

Member III
I use full strength vinegar for mildew and the more stubborn bird crap on my deck and it works quite well, but I haven't yet used it on fabric.
 

David Grimm

E38-200
All my sail and other covers went right in the washing machine with some tide when I purchased the boat. The green came off and they looked great. I laid them out on the plastic dock and with a garden sprayer applied star brite water proofing. Now the dock is waterproof too. 4 yrs later they're all still beading up water!
 

markvone

Sustaining Member
Here's an idea, for driveway sized cleaning, sails, sail covers, etc., I'd get a new poly tarp of the correct size and dedicate it to sail and cover cleaning. Keep track of which side is always up/down. Lay it down first to provide a clean, smooth, non-abrasive cleaning surface for the big covers and sails. I would use it on the lawn also to minimize dirt and grass stains. Works for smaller size jobs as well. I'm currently downsizing and I no longer have room for the glass patio table top dedicated to boat cover cleaning :( .
Mark
 
Top