Procedures for killing mold/fungus

[seacoyote]

My boat has signs of mold spores and fungus in the lazerette. I have created an airflow to help alleviate the problem, but what is the best procedure to kill the mold/fungus without harming the wood or caulking?

Thanks in advance,
C. D. Hunter

[Meerkat]

I think vinegar is quite popular for that.

[Paul Pless]

mild bleach and water solution

[seacoyote]

Meerkat - Please forgive me if my questions seem stupid.

1) - Any particular type of vinegar? (wine, apple cider, white)
2) - Do I apply it in full strength or do I dilute it?

3) - I was thinking of using a garden sprayer to apply the vinegar solution, would that be the best way?

Thank you,
C. D. Hunter

[John Bell]

You sure about that, Meer?

I'm not optimistic that a weak acetic acid solution (vinegar) will have much of an impact on mold spores. Spores are usually pretty tough to kill.

(Also, did you know that vinegar is actually produced by a fungus!)

Anyway, in my business we are often concerned with killing mold, fungus, and more importantly, their spores. My experience is that outside of heating things to greater than 140F, oxidizers are the best killers. Paul's suggestion of a mild bleach solution (sodium hypochlorite, an oxidizer) has a better chance of killing the bugs than does vinegar. I'd try that first. And it won't make your boat smell like sour wine or an antipasti!

[Bob Smalser]

Bleach works wonders to clean off the active growth....but you aren't really killing anything.

The spores are everywhere. 55 degrees and higher, high moisture, and stagnant air brings them to life again.

You have to alleviate the conditions to prevent re-occurrence.

[Paul Pless]

Bob,

You are correct, your comments lead to me to wonder if this would work to combat furure fungal growth: At my laboratory we use a quatrinary ammonia solution for organic cleanup and washdowns of some fairly large areas. The specific product is Qautricide PV15 manufactured by Pharmacal. In addition to its detergent and disinfectant properties, it also has deordorant fungicides and mildewstats. I wonder what its ability to combat mold and mildew would be in a marine environment.

Paul

[Russell Sova]

Now this is going to really sound ridiculous but I had a small leak in a boat once and I got rid of the leak but still had a small amount of water that qwas trapped in the boat. I put in mortar mix to absorb the water and prevent mold via the lime in the mortar. When I disassembled that boat there was no rot. I should have sold it like everyone was telling me to do, but I was afraid of selling someone a rotten boat. I've seen wood forms used for concrete used for years and I've never seen one with any rot anywhere. We've used the same forms at work for 20 years off and on!
This may sound wild but I'd paint on a dilute mortar if it's in a place no one will see, then sand and paint over it after it dried. The low Ph in the lime prevents mold I believe.

[Mrleft8]

Sunlight. Unfortunately no one's been able to package it efectively, so it's hard to bring it into places where fungi tend to develop...

[hoz]

How about antifreeze?
http://www.angelfire.com/nc3/davecarnell/rot.html

[John Bell]

THere are lots of things that will kill spores. The problem in wood is getting a killing dose into its porous structure. As I've already stated, oxidizers are best for this application. Among other types of antimicrobials, we sell peracetic acid, hypochlorite, and sodium bromide for spore control. These kill quickly, and if you get enough of them in there, the effect lasts a long time. As Paul points out, quats are also good for killing active cultures. We have those too. There are also chemicals that can be applied to inhibit growth such as isothiazoline, but they are pretty nasty to deal with. The best solution would be as Bob points out, is to eliminate the conditions that are conducive to growth, ie temperature and humidity.

[ken mcclure]

Okay. Again ....

Mold needs five things to grow and flourish:

1) A food source. Soap scum is a real good one, for instance.
2) A temperature range in which you and I would be comfortable.
3) Moisture.
4) Darkness.
5) Dead (unmoving) air.

Break any of these and the mold will start to have a hard time.

[Popeye]

When there is a fungus among us, I think the dividing line is between the words 'eliminate' and 'control'.

Bleach is cheap, safe and easy on the environment since it breaks down and will control the problem if used routinely.

Short of an autoclave, there is no 'eliminate', since nature is all powerful and wins every war if not the battle.

[seacoyote]

Fellow Formites - I appreciate the responses and
I have considered using bleach, but an aqaintance of mine pointed out what bleach can do to clothing and I was wondering what it could do to the cotton in the seams of the boat?
I installed a fan that runs 24X7 to help alleviate the problem, but I would really like to eliminate the mold spores. Has anybody had any negative results when using bleach? Has anybody on the forum tried using a glycol/borate solution with positive results?

Thank you,
C.D. Hunter

[Donn]

C.D. Your hunch is correct. Bleach eats textiles. Dilute bleach eats less textile, but kills fewer spores. I'd use a combination of mechanical processes. Mild soap and a brush to remove surface mildew, rinsed thoroughly, and better (worse?) conditions to discourage regrowth.

[JimJ]

I believe hyogren peroxide will kill mold.

Where is thechemist when you need him?

Have a look at

http://www.umm.edu/careguides/allergy/allergy_moldcontrol.html

[Meerkat]

If I was going to use vinegar, I would use white vinegar, undiluted (it's already dilute in the bottle as mentioned - pure acetic acid is narsty stuff!).

I wonder if this isn't a job for CPES? It will penetrate the pores and seal the spores from moisture and air...

[Bob Smalser]

If the boat's been in the water a while, I doubt any bleach will get thru to your cotton caulking....providing you just scrub with it and not let it sit.

[alteran]

I agree with them all. smile.gif

Now what varnish is best?

Sorry but I couldn't resist.

Al.

[ken mcclure]

Okay. Bleach will harm textiles - if you get it on the textiles. Bleach should not harm the hard surfaces and will kill mold and render the "food sources" relatively useless.

Do not use bleach if there is spilled gasoline present. Fire is the rapid oxidation of fuel. Bleach is a rapid oxidizer. 'nuff said?

Mold spores, and indeed many spores, are almost impervious to anything you can do to them that would not also destroy the boat. Mold spores are present in the air, and it's not feasible to keep them out of the boat. All you can do is kill any fungus that is growing and prevent the further on-site production of spores.

In order to halt the process, you need to break the chain by changing or eliminating one of the five items mentioned above.

So.

Clean the area thoroughly, removing any and all residues that could provide a food source.

Wipe the area with either an EPA-registered disinfectant or with a solution of bleach and water. Wear a respirator. Make sure that the area is wetted sufficiently so that the disinfecting solution stays wet and in contact with the surface for at least 10 minutes (or as specified by the disinfectant manufacturer).

Keep the area as dry as possible.

Provide as much air flow as possible.

Provide as much light as possible.

[Popeye]

Bleach and EG (antifreeze) are also going to be corrosive on metals they come in contact with. Hydrogen peroxide is fairly safe stuff, the food grade kind (in solution)is also a mouth rinse, and is used in teeth whitening gels/strips.

Nobody has mentioned ozone and UV light are also good at destroying tiny organisms. Although this approach may be a little too exotic for most of us.

Another thought I have is ...mercury ... as is found in mildew resistant paint used in bathrooms.

after lunch edit to add:: (the old brain aint what it used to be)

Trisodium Phosphate (TSP) sold in beer/wine making supply stores is another good cleaner for mildew. Caustic soda , is used in breweries to clean the S/S tuns and will kill most germs, ammonia is a good cleaner , but more difficult to use safely.

[ 07-08-2004, 01:25 PM: Message edited by: popeye ]

[Scott Rosen]

There is an easy, safe and inexpensive way to do this.

First, empty and clean the lazarette with a mild solution of TSP and warm water. You can add a small amount of Chlorox if you want. Diluted heavily, it shouldn't harm anything in that part of your boat.

Next, make a solution of water and borate (Tim-Bor), and spray it with a plant mister on all of the surfaces in your lazarette. Let it dry, which shouldn't take more than a couple of hours; replace the stuff, and you're good to go. The borates will prevent the growth of mold, mildew and rot fungus.

You can do this every year when you are decomissioning your boat.

[Meerkat]

Originally posted by alteran:

Now what varnish is best?
http://media5.hypernet.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=002474

[Meerkat]

Scot; Great post - thanks for the tip.

[RGM]

Scott summed it up pretty well. Plus changing the environment in the lazarette as the others have suggested. In the Seattle area you can get Timbor products (powder & rods) from Wood Care Systems in Kirkland, 1-800-827-3480. Or Kemi-K Products on Aurora Ave. N. 206-525-3600. In the past we've used the outfit in Kirkland. Good luck and be careful when working overhead (eye protection).

[Meerkat]

How does this stand up to showers? Sure, you wrap a shower curtain around you when you take a shower on a boat (unless you're rich enough to have a boat with an actual shower stall and not the only standing room in the head), but what about humidity and splashing?

[seacoyote]

Scott - Thank you for the informative post. Your process sounds like the route I will take.
RGM - Thank you for the local list of suppliers.

C. D. Hunter

[Dan Lindberg]

Interesting and timely string.

Suppose the mold/fungas isn't on a boat, but in a crawl space instead.

What about just using/spraying on that green wood preservative??

Dan

[Scott Rosen]

TimBor is a fungistat, not a fungicide. Unlike bleach or detergent, it won't remove existing mildew and mold stains. That's why you need to wash the area first. It will, however, prevent the growth of new stuff once the area is clean.

It's water-soluble, so if you use it in a shower or on any exterior surfaces, it will wash off. However, you can paint over it, which will stop it from washing off.

There have been some studies which show that wood treated with borates can be painted and epoxied without any loss of adhesion.

If I were building or repairing in plywood, I would saturate the endgrain with borate solution and then seal with epoxy.