Wood Chemotherapy?

[Howard Thomas]

Is the ratio given for the Home Brew Glycol Solution of Borates (50% glycol anti-freeze, 28% borax and 22% boric acid) for material weights or volumes?

[KeenEddy]

I can't answer your question definitively, but volume sounds the logical route to go. I am curios as to your brew though. On what and how do you intend to use it? I'm not read-up on the anti-freeze. Is it any anti-freeze that contains or, is glycol?

[Ilan Voyager]

Originally Posted by Howard Thomas

Is the ratio given for the Home Brew Glycol Solution of Borates (50% glycol anti-freeze, 28% borax and 22% boric acid) for material weights or volumes?

The ratios are in weight. It's simpler to use to use sodium octoborate as it disolves better.

Home Made Octo-Glycol
40% solution of sodium octaborate in ethylene glycol; 27% borate content Glycol 60% octoborate 40% in weight.

Boil at about 120 celsius degrees to evaporate the water of cristalisation of borate. The mix is generally dissolved with water (one part octo glycol, one part water in volume) for soaking or spraying.

You can use CONCENTRATED antifreeze (the green one). The metallic salts doping added to the antifreeze for anticorrosion purposes does not harm.

Do not hope to correctly glue anything after a borate based treatment. If you plan to glue after (specially with epoxy) it's better to use mono ethylene glycol or antifreeze alone. It's also a very efective rot treatment. It seems that mono ethylene glycol improves the adhesion of epoxy on light woods.

[Jim Kartz]

What are you going to use this stuff for?If glue wont stick to wood treated with this brew, how will paint ever stick? dont know if this is true,but an older man once told me to help prevent rot put rock salt in bilge.

[Guest20100203]

There are much better ways to protect you lumber from the bad things you may be trying to fend off then dumping antifreeze into your bilge. The health risks alone should be enough to scare you off, but if not, read the side of the cans those chemicals come in or better yet, the label on a jug of antifreeze (that's what you're trying to make) If interested in a more up close and personal tack feed some to your uncles cat ( or dog if you're a cat person) that you don't like, but you must watch it suffer and die or you'll loose the whole point.

The living spaces in you yacht will be ill suited with this lurking in the lumber. Yes, it kills little beasties, but generally what kills them does similar things to us. Get a grip, use good materials, good technique and sound processes and you'll be fine. Use homemade goo's from the radiator and you'll wish you hadn't, so will your boat.

[Ilan Voyager]

Originally Posted by PAR

There are much better ways to protect you lumber from the bad things you may be trying to fend off then dumping antifreeze into your bilge. The health risks alone should be enough to scare you off, but if not, read the side of the cans those chemicals come in or better yet, the label on a jug of antifreeze (that's what you're trying to make) If interested in a more up close and personal tack feed some to your uncles cat ( or dog if you're a cat person) that you don't like, but you must watch it suffer and die or you'll loose the whole point.

The living spaces in you yacht will be ill suited with this lurking in the lumber. Yes, it kills little beasties, but generally what kills them does similar things to us. Get a grip, use good materials, good technique and sound processes and you'll be fine. Use homemade goo's from the radiator and you'll wish you hadn't, so will your boat.

I have 25 years of experience of naval engineering mainly in warships (from 18 to 264 meters), wooden fishing boats from 7 to 35 meters, and racing high tech saili multis from 12 to 22 meters.

The recipe of ethylene glycol ans borates is an very old one, since at least the 1940's and was used on the wooden mine sweepers.

In general discussion, all chemical are harmful, but there are degrees in danger. I prefer work with borates and ethylene glycol than to sand CCA treated wood (copper-chrome arseniate... a good mix of poisons and heavy metals) or some very volatil organo-compounds which goes directly in your brain or liver.


Borates are minerals (salts) without any evaporation and of very low toxicity: a bit more than table salt and less than aspirin. They are remplacing now the CCA for wood treatment. Octoborate may be found as foliar fertiliser under the brand Foliarel at very good price.

Ethylene glycol is toxic to any living organism and very effective for killing fungus. Its sweet sugared taste is a mortal tramp specially for dogs, but when mixed with borates the taste becomes truly horrible. Prolipropylene glycol is a non toxic alternative when you want an hygroscopic effet with migration of the borates in the wood by osmosis. Ethylene glycol is far less dangerous than thinners, isocianates or other niceties.

The mix Ethylene glycol-Borates is expensively sold under the brand Bora Care and consorts.

This old recipe has many advantages on old "classic" wooden boats, which do no rely structurally on glues but are fastened. The wood of these boats is very humid, even wet so all the treatments using hydrocarbures ( white gas or thinner) solvents are ineffective as the treatment does not penetrates at all in wet wood, and very little in dry wood.

Borates and ethylene glycol penetrates very well in humid wood. On fishing boats and old boats is the cheapest, safest and most effective treatment I know for fighting rot. Maybe it detracts on luxury boats but we have saved from death a friend's swedish old skerry cruiser with this soup.

The requisites of adhesion of paints is not the same as for structural glues, and it does not give problem at least with oil based paints. Make always a trial before.

Personnaly I use ethylene glycol to treat the woods like the cupres lusitanica I use in strip planking/UD glass/epoxy with no problem. The woods are often infected by spores of fungus.

Always use chemicals with caution and all the safety requirements. It's easy to find in internet the security sheets (for example http://www.nsc.org/ehc/ew/chemical.htm)

You'll find good tech info about borates and rot/fungus treatments in the internet site of the FPL US Forest Industry Laboratory http://www.fpl.fs.fed.us/about.htm.

It's better to be fully informed than to have epidermic reactions.

The Foliarel product is manufactured by the Italian company Società Chimica Larderello (www.scl.it) and it appears they have more specific stuff for wood treatment.

[D'ARTOIS]

......Never too old to learn......