Cleaning canopy

[FlyingDutchman]

When we bought our (used) boat last year, it came with a brand new canopy.
In the fall, we took off the new canopy and put on the old one, which had been in a plastic bag. Then we covered the boat with a cheap plastic sheet to avoid the old canopy from geting wet as we don't know if it is watertight.

The problem is, that the old caopy stinks and is covered with black fungus (mildew?). In a couple of weeks we will install the new canopy again and we want to try to clean the old one so that we can use it again next winter.

Any recommendations on how to get the black stuff of without damaging the material?

 

[charles_reed]

Oxalic acid solution

Apply for about 10 minutes than wash off with plenty of clean water.

 

[BarryH]

Re: Oxalic acid solution

Oxalic acid solution will be a bit harsh. I'd suggest using a weak solution of Milton fluid. It'll get rid of the mildew with maybe one or two applications. Rinse off with plenty of clean water. If you want to go the whole hog you could reseal with an application of Grangers.
I'm taking it as read that your canopy is made from acrylic canvas.

 

[pvb]

Milton....

Milton, as I'm fond of saying, is just a dilute solution of common household bleach. If you're tempted to use Milton, save your money and use bleach instead.

 

[BarryH]

Re: Milton....

Yes but your average person does not dilute "household" bleach enough which is why I said use milton as when its diluted it'll be somewhere near the right strength.
Also as an aside Milton type sterilising fluids contains soduim hypochlorite. Household bleach also contains sodium hydroxide which damages acrylic canvas. Not too good if to strong on boat canopies.

 

[pvb]

Sodium hypochlorite...

Sodium hypochlorite is bleach.

 

[BarryH]

Re: Sodium hypochlorite...

Yes I know but I'm not going to get into a pointless argument over household cleaning solutions/products.
A few years ago I had a customer come to me with an awning that I made him. The fabric, acrylic canvas, was going rotten and was covered in holes. As it was only 18 months old I took a sample of the fabric back to the manufacturers. They had a look and straight away said it hade been cleaned using bleach. Bleach attacks acrylic. They said to me to advise customers that "household bleach" damages the acrylic. They also advised that cleaning should be carried out with a mild solution of milton type sterilising solution for heavy soiling, including mildew, and for general cleaning a solution made up from soap flakes.

Long and short of it, advised not to use bleach. Milton type ok. I felt sorry for the guy and made him a new awning cover at cost. Not good business practice but the recommendations that have come from that one job has more than paid for it.

 

[BrendanS]

Re: Sodium hypochlorite...

I don't know how many times we've had this converstion, but I'll repeat again.

'Bleach' as bought from UK supermarkets is not a pure sodium hypochlorite solution. It's a whole mix of chemicals, including sodium hydroxide, whiteners, bleachers, surfactants etc etc etc etc

 

[FlyingDutchman]

Re: Sodium hypochlorite...

Thank you all for your input!

I will not use diluted bleach (although I don't know what fabric it is, it looks like cotton, but seems a bit stiffer).
I will have to try and find the Dutch equivalent of this Milton fluid.

Thanks again and best regards,
Jan