Black on the bimini canvass

So the canvass bimini is off and I need to clean it up and do a wee bit of sewing in one section. What do you recommend for cleaning the canvass - bleach or hydrogen peroxide, or something else?

On my stamoid I use the mildest bleach solution that will work, assuming your stains are mold based. Start weak and go stronger if needed. Rinse very thoroughly.

I only bleach clean as needed, not as a regular thing.

For spots on the underside I mix a mild solution in a spray bottle, then spray it on a paper towel and spot clean.

I did the same thing when I had sunbrella. I know it's not great for the fabric, but it is often the only way to get it clean. I've tried mildew removers and peroxide based cleaners. They didn't work at all for me.

Sunbrella can take bleach.

Mix 3/4 bleach, 1/4 cup mild detergent (Deft), 1 gallon of water. I use a sponge that is covered with a nylon mesh ( like a bug sponge for cleaning a car windshield). Rinse well.

Comodave said:

Sunbrella can take bleach.

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If top is Sunbrella bleach / soap solution is the way to go.
Complete Sunbrella cleaning & care directions available on Bacchus website - Useful Links and in TF Library Misc heading.

I would strongly suggest, if possible, to remove the top and soak it in the solution. Then rinse & retreat for water repellency.
1st - it takes a little time to work and it gets both sides at the same time.
2nd - you will need to rinse multiple (~2-3X) times and easier off the boat
3rd - you will need to retreat again best done off the boat
4th - Recurrence more likely if just doing spots while on the boat.

Sunbrella recommends 303 Fabric Guard (not the same as 303 Protectant) and it works well when applied per direction & tips provided... not as well if applied differently or sub-optimal conditions.
NOTE: Avoid getting 303 Fabric Guard on vinyl windows! (or 303 Protectant or other vinyl treatment on Sunbrella)

We just did this a few weeks ago. Following Sunbrella’s directions but with less bleach, just to be safe:
1/4 c Dawn detergent
1/2 c bleach
1 gal water

Took the bimini down, laid it out on the top deck, and used a soft brush on a stick. We let the solution sit on it for a couple minutes, then rinsed very well. Flipped it over and did it again.
We’d had black mold all over the thing and now it looks brand new. Was much easier and faster than we’d anticipated.
How many times will I be able to say that?

Sunbrella, a synthetic material, can be bleached without harm.

The thread used to sew the canvas could be cotton which will be harmed by the bleach and eventually disentegrate.

Polyester and PTFE/Fluoropolymer threads will not be harmed by bleach.

Find some excess stitching on the cover and remove a short length of thread. Heat it with a soldering iron and if it melts, it's not cotton.

Anybody had any issues if some of the bleach solution got onto their strataglass?



Taking my bimini and enclosure down is an all day affair complete with quite a few curse words and busted knuckles. I generally only do it for hurricane prep. So I wash in place. I soak the curtains down with fresh water before, during and after the bimini cleaning to try to lessen the bleach exposure, but I'm sure some still gets on them.



I've done this three or four times and haven't seen any issues on my strataglass but it still concerns me.

syjos said:

Sunbrella, a synthetic material, can be bleached without harm.

The thread used to sew the canvas could be cotton which will be harmed by the bleach and eventually disentegrate.

Polyester and PTFE/Fluoropolymer threads will not be harmed by bleach.

Find some excess stitching on the cover and remove a short length of thread. Heat it with a soldering iron and if it melts, it's not cotton.

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Agree w above but IMO anyone using cotton thread on marine canvas should be shot! It will only last a couple seasons... maybe one in the south. Any commercial shop should be using UV treated poly as a minimum and offer Tenara or similar as an upcharge but worth it especially in the south.

I was talking to the Sunbrella VP at the Annapolis Boat Show. He said no problems with bleach, they had a piece of Sunbrella soaking in a jar of straight bleach as a display.

I would absolutely not have any canvas made without using Tenara or equivalent thread. If the shop does not want to use Tenara, find a new shop. Tenara is more slippery and so you have to set up the machine a bit differently. The difference in initial cost should not be excessive since a spool of Tenara is about $120 and will do a complete boat. It will last forever. No poly thread and absolutely no cotton thread. I actually have never seen cotton thread used on canvas.