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Canibul · 22-12-2015, 04:15

Putting an argument in quotation marks doesn't make it true. Think about that part saying bleach doesn't work on porous surfaces. Guess you can throw away the laundry detergent then.And it should no longer worry you to splash bleach on your shoes, or clothes, or anything porous. You see, bleach doesn't work on porous stuff.

Somebody on the internet said so. Good enough for me.

sparrowhawk1 · 22-12-2015, 04:24

Agreed. it's not the quotes, it's the scientific studies. something about molecules. A quick Google search will explain it.. PS that somebody was OSHA, FEMA, and the EPA if you don't like government: private investigators LCC and if you don't like reading: YouTube - mold removal myths. Myth number 2

thinwater · 22-12-2015, 06:50

Quote:

Originally Posted by sparrowhawk1

Agreed. it's not the quotes, it's the scientific studies. something about molecules. A quick Google search will explain it.. PS that somebody was OSHA, FEMA, and the EPA if you don't like government: private investigators LCC and if you don't like reading: YouTube - mold removal myths. Myth number 2

It comes down to how porous.

Non-porous surfaces are easy. Generally it can be scrubbed off and bleach will work too.

Very porous surfaces (textiles) are accessible to bleach, explaining why bleach works in the laundry. Bleach would even work on drywall, if you could truly soak the wall, which would of course, destroy the wall. This is a second reason we sometimes say bleach is ineffective; mildew can go deep, and when it does it is nearly impossible to kill.

Slightly porous surfaces, and even biomass layers, are the problem. The mildew can grow into them, but the bleach cannot follow, often for reasons of charge. In those cases, non-ionic chemicals work better (one of the reasons cholramine is better in water mains), though if the mildew is well established, it is often hopeless, or at least, impractical.

sparrowhawk1 · 23-12-2015, 09:07

run clean hot water through your sprayer when you're done otherwise it will look like this in the morning and I sprayed all of the fluid out of it, thought it was clean of borax. This is a picture of the nozzle that I had to take off my pump up sprayer totally clogged. Edit. I just realized that it could have clogged today if I didn't totally dissolve the borax which is a bigger possibility

wsmurdoch · 23-12-2015, 15:39

Quote:

Originally Posted by zboss

Knife and scrappers. Really.

Once mold gets into caulk, its too late. Replace the caulk.

I've been able to bleach a bead of white silicone caulk that mould had turned black. Here is the method. Start with about a tablespoon of bicarbonate of soda. Wet it with Clorox bleach until you have a paste sort of like uncooked biscuit dough. Spread the paste over the mouldy caulk. Cut out a ribbon of cling film, saran wrap, or whatever you call the thin food wrap. Press the film over the paste. Go to bed. Take a look at it in the morning or maybe in the afternoon. When the mould is gone, or maybe just bleached white and now invisible, clean up the mess with a rag and water. You are done.

This is not an original idea. Like everything else in life that I used to learn from the backs of cereal boxes or record jackets, I learned on the internet. It was from a site for apartment renters with advice for dealing with the bathtubs that renters had never cleaned. The bicarb just holds the bleach; sawdust would be just as good. The cling film keeps the paste from drying out.

Anyway, it worked for me last year. It did not explode, and my fingers did not fall off. Yours might.

I got rid of the black caulk in the head that I was afraid of scraping out and replacing.

thinwater · 23-12-2015, 16:06

Quote:

Originally Posted by wsmurdoch

I've been able to bleach a bead of white silicone caulk that mould had turned black. Here is the method. Start with about a tablespoon of bicarbonate of soda. Wet it with Clorox bleach until you have a paste sort of like uncooked biscuit dough. Spread the paste over the mouldy caulk. Cut out a ribbon of cling film, saran wrap, or whatever you call the thin food wrap. Press the film over the paste. Go to bed. Take a look at it in the morning or maybe in the afternoon. When the mould is gone, or maybe just bleached white and now invisible, clean up the mess with a rag and water. You are done.

This is not an original idea. Like everything else in life that I used to learn from the backs of cereal boxes or record jackets, I learned on the internet. It was from a site for apartment renters with advice for dealing with the bathtubs that renters had never cleaned. The bicarb just holds the bleach; sawdust would be just as good. The cling film keeps the paste from drying out.

Anyway, it worked for me last year. It did not explode, and my fingers did not fall off. Yours might.

I got rid of the black caulk in the head that I was afraid of scraping out and replacing.

Yes, this is a good method.

No, saw dust is not as good. The advantage of bicarb is that it is inert toward bleach and helps keep the pH down at about 9 rather than up at 11 where it would normally be (bleach is many times more reactive at 9 pH). I've used colloidal silica before (cheap if bought in bulk), though it lacks this buffering effect. Sawdust, on the other hand, reacts with bleach and neutralizes the bleach, reducing its effectiveness.

Vinegar + bleach makes a very effective sanitizing agent for this same reason (lower pH), but NEVER try this with full-strength products--chlorine gas is generated in high volume. This is ONLY safe at high dilution and not in confined spaces. Never use strong acids (HCl, Phosphoric....).

svlamorocha · 25-12-2015, 05:14

Quote:

Originally Posted by travellerw

Although not technically true, I just think of Boric Acid and concentrated Borax.

I have used Borax when I couldn't get Boric Acid. It seems to work as well on mold.

J

You remind me of when I had a real job as head of sales and marketing for US Borax.

You are right. Boric acid has about 56% boric oxide aka B2O3. Normal borax (which is sodium tetraborate decahydrate aka 10-mol) only has about 36%. 10-mol is mostly used in household applications for traditional reasons; Ronald Reagan and all that keeps it on the Walmart shelf. Boric acid and other borates have replaced it in most industrial uses except those that require pH buffering because the 10-mol is more expensive to transport and it will "cake" faster.

There are certain applications for which the form makes a difference. If acid pH is preferred then you want boric acid. Just make sure it is "powder" and not "granular" to make it easy to apply.

You could also apply vinegar first (to kill with low pH) then a wipe with clean water (to avoid stains from leaving the vinegar there) and then a borax or boric acid spray as biocide to prevent recurrence.

By the way, if you want to prepare a concentrated solution it helps to mix boric acid and borax to form disodium octoborate aka DOT that has higher solubility. You can also buy ready made DOT that is fine and easy to dissolve. Same product is sold under various brands: Solubor fertilizer, Timbor wood preservative and Octabor generic chemical.

IMHO it is a pity that BS litigation in the US keeps serious companies that are big enough to be a target for lawyers out of providing cheap, easy and effective solutions for mold, wood decay, etc.

C

Sent from my GT-I9192 using Cruisers Sailing Forum mobile app

Blue Crab · 25-12-2015, 06:14

10-mol

That sez it all for me. Throw in The Ronald and bud, ya got yerself a vote!

I know that's chemistry dirty talk. In fact I think Lamerocha got that off the label of Dr. Bronner's. Seriously, tho, thanks. Imagonatryit.

And thanks to Canibul for the word on why I have fruit flies. Makes sense if ya can put down yer MaiTai long enough to think about it. The vinegar seems to work for a few weeks at a time, and the odor is ok after a few hours of airing out. Not so with bleach, for me.

The first thing I did with my good old boat was rip out the 40 yr old headliner and toss all the cushions, then painted everything light.

Next was aligning two heaters, in winter, with two yr-round fans to heat/vent the entire 29' feet of yot. This helped with both mold and condensation. My current mania is drilling vent holes in the cabinetry and putting some forced air in there.

I've also purchased an airfilter/HEPA machine that sleeps with me in my winter berth. I don't know how it puts up with my snoring.

I mention all this because I became allergic after buying this boat, and now carry an Epipen, inhaler, RXes, etc. If I weren't so ancient, I'd have to consider another lifestyle. Mold is serious bizness.

sparrowhawk1 · 25-12-2015, 06:40

Merry Christmas everyone. But the war with mold does not rest. Lamorocha so what is best: borax, boric acid or the combo of the two.
Blue crab I have allergies too and I found putting a furnace filter behind a box fan lets me breathe easy. you can even get one thats a HEPA filter and a small 12 volt box fan. Edit. By best I mean for preventing the mold coming back.

Blue Crab · 25-12-2015, 06:50

Good tips. Thx. I've even put a HEPA on my Shop Vac for project cleanup.

sparrowhawk1 · 25-12-2015, 07:00

I am amazed at how much dust gets collected on the back of my small fan filter. I think everyone should do it not just people with allergies

exMaggieDrum · 25-12-2015, 07:55

Back to the OP's original question: what can kill/remove black mold in caulking? If it is in the caulking, absolutely nothing IME. It has to be removed and replaced. I use bleach in our shower at home but do not like using it on the boat. Gord May had the best answer I have seen so far on the subject. You can kill the mold on many surfaces, but not all, and it is almost impossible to kill th stuff when it gets under the immediate surface of any material. Prevention is the best method - but that is very hard too.

I know there were a lot of people using ozone generators on boats for a while but I always worried that the high energy ozone (free radical oxygen) would also attack any kind of rubber (seals) and other organic and non-organic compounds. It is probably very tough on mold growth though.

pmagistro · 25-12-2015, 08:02

Home Depot sells a product called "Concorbium Mold Stain Eraser". It's about $15 for a jug, you mix it with hot (tap) water, let it sit for ten minutes, then sponge it over the mold stains. It's done a great job removing the mold stains from fiberglass surfaces in my boat and I used it yesterday on my grandmother's vinyl golf cart seats to good effect as well.

thinwater · 25-12-2015, 09:10

Quote:

Originally Posted by pmagistro

Home Depot sells a product called "Concorbium Mold Stain Eraser". It's about $15 for a jug, you mix it with hot (tap) water, let it sit for ten minutes, then sponge it over the mold stains. It's done a great job removing the mold stains from fiberglass surfaces in my boat and I used it yesterday on my grandmother's vinyl golf cart seats to good effect as well.

Like other Concrobium products, it's overpriced stuff marked up because it says "mold."

Buy Oxyclean for 20% the price. Basically the same chemistry. More to the point, you probably already have it. Good stuff.