Author Topic: BORAX WOOD TREATMENT - eco-friendly wood boring insect and rot treatment  (Read 19980 times)

Offline Wendy

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    • Permaculturing in Portugal
Many people are using borax as an ecological timber preservative as it has insecticide and anti-fungal properties. It's not flammable, combustible, or explosive, and in liquid form is flame-retardant. It has low acute oral and dermal toxicity, is non-carcinogenic and non-toxic to humans and pets. It avoids the hazard problems of many liquid insecticides by using only water as a carrier.

But the term borax is used for a number of closely related minerals or chemical compounds that differ in their crystal water content, so which to use? 'Borax' usually refers to sodium tetraborate decahydrate. It's available here from the agri for roughly €1/kg. It's used as a soil additive for olives, vines and fruit trees. However, Disodium octaborate tetrahydrate or DOT, is the 'borax' which is the treatment of preference for timber. It's a boron salt available as a powder concentrate, ready to dissolve in water, designed to treat timber by brush, spray or dipping. It can also be used in most wood preservation situations to replace other less ‘friendly’ contact type insecticides, including Permethrin. In a 5-10% solution, the 'kill rate' is much greater than a saturated solution of sodium tetraborate decahydrate.

The 'kill rate' may be much higher but, unfortunately, so is the price, especially for small quantities. There's no way I've found to source DOT at anything approaching the price of borax from the agri, but for those who want a more robust treatment for their timber, then buying in bulk can make a huge difference. Enough to make it substantially cheaper than equivalent chemical timber treatments or off-the-shelf 'eco' products.

There is a company in Devon who supply DOT mail order. A single 1kg pack of DOT, including VAT and delivery to Portugal, costs £86.44. This will make 25ltrs of 5% solution which is sufficient to protect 50m² of timber (2 coats), or 12.5ltrs of a 10% solution which is an effective treatment for 25m² of timber that's already well infested.

However, a 15kg trade pack of 6 x 2.5kg packs brings the price for 1kg, including VAT and delivery, to £35.61. Two 15kg trade packs of 6 x 2.5kg packs will bring the per kg price down to just under £30.

A few of us have just ordered a single trade pack. I figured this was worth making more widely known.

Offline Pip

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Re: BORAX WOOD TREATMENT - eco-friendly wood boring insect and rot treatment
« Reply #1 on: February 24, 2012, 10:05:53 PM »
thanks wendy! when i'm ready (if anyone's got any left) i'd love to split a pack with someone x