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Mildew in the Cabin

3K views 22 replies 16 participants last post by  pdqaltair 
#1 ·
I've been doing some research for PS Magazine on mildew and I have a question. But first some background:

--We've looked at CaCl2 and other desicants. This is only going to keep the cabin dry if things are tight.
--We've looked at dehumidifiers vs. CaCl2. There are some small units that seem very useful. Article submitted.

We've started testing canvas samples:

--If kept low humidity (<60%) significant mildew is impossible to start, even if the samples are inoculated.
--Water repellant treatments help a lot. Synthetics (Sunbrella) are much more resistant than cotton. Obviously.
--Vapor treatments don't seem to do much. Perhaps some incremental difference in a situation that is nearly sterile, but we can see it.
--Bleach will kill it if you use enough (and related products), but it can grow back if the bleach is rinsed off. And you can't use bleach on upholstery or carpet.
--Vinegar will kill it and keep it away better, but use that on soft surfaces and you'll have to sell the boat... if you can.

And finally the question. It seems some very simple alkaline cleaners (TSP+borax+washing soda as well as variations) are quite effective--better than some "anti-mildew" products--for pennies. The trick is to use low concentration and not to rinse. The borax/phosphate residue is the thing. Phophates only seem to be a problem from cleaners going down the sewer (laundry) and we're talking about low volume spray cleaners that are not rinsed. Different. Sure, you can add organic surfactants (soaps) to increase effectiveness, but unless they are carefully chosen and biocide added (quat amines?) they themselves become mildew food.

What have you found most effective at preventing mildew return? Why?
 
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#7 ·
Yes, I hear that, but testing suggests it will only be effective in small areas with little ventilation (if there is effective ventilation it dissipates too quickly) that are dry and clean. I think we will see that it is a supplemental tool useful in some cases, after other steps are taken.

As you have suggested, it will not eradicate mildew from a damp boat.
 
#9 ·
chef, there's a strong biocide in tea tree extracts. Nail salons use it to cure nail infections, both fungal and bacterial. No idea what's in the gel but I'd bet the same active ingredient, which seems to sublimate very nicely, the tea tree oil can be quite pungent.

pdq-
I've found that if you keep things fairly clean and dry, good ventilation will stop mildew. But then again, I don't hang around swamps. I knew someone who used to work full time for Ford, going around the country examining AC systems in cars that had perennial mildew problems. They had no universal cure either, but using toxins (copper or tin or silver in micro-form or as base materials) seemed to be the best way to stop it from getting started, but if moisture built up, the crud would always follow.

Bleach of course will also kill cotton and some other fabrics.

But you missed two killers, ozone and UV-C. Like every other mildecide, they will kill it--but the spores are in the air all the time, everywhere. Killing it just provides good food for the next crop, unless you also clean away the food, and change the environment to someplace they won't grow. (By keeping it dry, or toxic, or outright wet.)
 
#10 ·
One winter storage cheap solution is kitty litter in buckets or pans (the more surface area the better) in all the cabins. Even sealed up the boat can start the season with no mildew to cleanup. We also remove all fabrics, cushions, etc.

But you may be driving for solutions that work while commissioned, we haven't had much problem with that up here.
 
#13 ·
Just driving for ideas worth testing side-by-side, and many have been offered. Good.

Kitty litter works by buffering the humidity and keeping it stable. We tested the silica gel type and found it to be the most economical product of it's type. An hour in the oven at 250F gets it ready for re-use, year after year.
 
#15 ·
Yup, started a thread on this stuff a few years back when I first heard of it. I reload twice a year now. Just ordered the spring supply.

I'm not sure it will kill a runaway colony that got a head start, but it does a nice job of keeping it from coming back. They make a spray now, I wonder how that works for cleaning? I've found, for it to work best, you need to limit air exchange for a period of time.

The active ingredient is tea tree oil and the manufacturer explains why theirs is worth the month. Here's the link to the thread here:

http://www.sailnet.com/forums/general-discussion-sailing-related/70288-kanberra-gel.html
 
#14 ·
For winter storage,

I strip all the cushions and any soft goods off the boat, I have racks at home in the basement for everything.

Keep water out of the bilge.. with the mast down it's not a problem, with the mast up, I get some water intrusion into the bilge. I have a bolt that I can remove in my bilge that allows the most of the water to run out through the centerboard trunk. I pump out any residual every couple of weeks and air the boat out.

after stipping everything, I've been applying lemon oil to the bare surfaces. I leave all the drawers and lockers open, remove the floorboards etc. So far, so good.

In season, It hasn't been an issue.

I'll look into the kanberra gels, and sprays.
 
#16 ·
i clean my boat with vinegar without any problem of smelling like vinegar--which, btw, is a lot better than dying of black mold.....
mold in material is the key to dispo-ing that material as the fabric will disintigrate from the mold and mildew.
pricey chemicals labelled anti mold anti mildew are very harsh on asthmatic lungs....not to mention the short term only capoacity for killing mold--they do not address spores. vinegar changes pH to acid and the spores do not grow in acid.
 
#18 ·
I think the key here is that PS is trying to find solutions for mold on fabrics in the cabin, while I think many of us have focused on mold that is on headliners or on the hull. I've had success in using a combination of vinegar and tea tree oil, along with a Mr. Clean Magic Eraser (or the knock-offs of those). You just have to remember to shake the vinegar and oil, otherwise you wind up only spraying the vinegar. As mentioned elsewhere, the vinegar changes the pH, so the mold can't grow, and the tea tree oil kills the mold.

Now, ridding yourself of the mold stains, that's another story entirely!
 
#19 ·
The big thing for me was finding the source of moisture in my boat. I had a persistent small puddle of water on the floor of the head that took me months to track down. It turned out to be a very slow leak in one of the hot water heater lines that would drip a bit as long as the system was pressurized.

Once I fixed that I got a very dry boat and mildew stopped being an issue.

I did wipe down all of my hard surfaces with a tea-tree oil containing spray. I mixed in another ounce of pure tea tree oil (not cheap stuff) to make it stronger. I like how tea tree oil smells, so it at least made the boat smell nicely and killed existing mildew, but I can't say if it did anything about new mildew.

We do sail it about once a week, that helps.
 
#20 ·
Ewh, moldy fabric.

Washing machine, hot water, repeat every couple weeks?

Seriously, I'd bet spraying it with colloidal silver solution would work. Or tea tree oil, or any of the other antifungals. With porous natural fabrics, crud is supposed to infest them in a damp environment.

If you've ever sniffed tea tree oil right out of the bottle, I'm not sure that having it disperse to be breathed in a closed space is a great idea. We all do worse but still, it is an irritant.

What I can't figure is how Kanberra can sell it as a bio-active product (mildecide, fungicide) without getting flack from the EPA, who genearlly get upset about any claims like that without an EPA certification attached. Maybe because it is "organic" ?
 
#23 ·
Are there any laundry detergents with colloidal silver? That might be a good option for the fabrics.

Edited to add: aha! COCONUT RAIN ALL NATURAL LAUNDRY SOAP - Home Haven't tried it.
Since silver is quite toxic to bacteria and not biodegradable, it is highly restricted in sewage ordinances. Far worse than phosphate, for example, so that will never happen. PPB limits are common.
 
#22 ·
Not to be unkind, but a detergent with colloidal silver would be a good way to separate fools from their money, as the purpose of a detergent is to remove things from the laundry, and colloidal silver would only work if you let it dry on the cloth, leaving as much silver behind as possible.
 
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