16 March 2012

Treating the bamboos

Bamboo is a very sustainable and also durable material as long as you treat and maintain it correctly. A post of maintaining the bamboo structures will follow later but currently we are working on the pre-treatment.

Last week we received our first batch of bamboos. All the fungus and other impurities were washed off and last weekend we got the bamboos into the treatment pools. The bamboos should be mature and fresh from the forest when treated. Our bamboos were fresh when we received them but start-up at the site took longer than expected so some of them might have dried too much before treatment. We'll see.

The goal of the treatment is to fill the cells of the bamboo with salt to prevent insects etc. from eating their way through it. Traditionally the bamboos have been soaked in a local body of water, preferably sea water, for some weeks but the modern way we are using includes use of chemicals.

The recipe for the bamboo bath is 95% water, 2,5% Borax and 2,5% Boric acid. Borax is a salt and a commonly used preservative. Boric acid is an acid used in e.g. rat poison. These chemicals are irritant so proper protective equipment should be worn when dealing with them. A thing we didn't know beforehand was that here in Cambodia these chemicals need to be imported and thus the delivery time is 4-5 weeks. Fortunately we were able to buy the left over chemicals from Chi Pat eco-lodge project and got them faster.

The chemicals come in granular form so it is best to dissolve them in boiling water first. How you do this depends on the circumstances you're in. In our case an open fire was made and a barrel of 100 liters was placed on top. Since the chemicals had been stored outside for some years they weren't exactly granulate anymore but came in large lumps. They were still usable but had to be hammered to smaller pieces and boiled somewhat longer than expected.

The treatment pools we built are 8x2x1m so excluding the volume of the bamboos this means more or less 5000 litters of water. Having to use a regular hose it takes some 8 hours to fill both of the pools.

The bamboos and the water in the pools must be mixed every now and then to make sure all the bamboos get evenly treated and the salt doesn't start christallizing on top of the water. Also some mixture must be added every now and then.

After a two-week bath the bamboos will be set vertically to dry and after some more washing and treating will follow but more about that later. Our next batch of bamboos just arrived to the site and is waiting for their turn to be washed and treated.

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