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< prev - next > Manufacturing handicraft process industries Wood and bamboo KnO 100336_Bamboo Preservation (Printable PDF)
Preservation of bamboo means:
sound management in storage, and in cutting time: cut the bamboo in the season when
the starch content is low;
attention to details such as keeping the bamboo dry:
protect the bamboo from splashing rainwater (build the roof with an over-hang),
allow the bamboo to dry quickly and completely after the rain has stopped, avoid
contact with soil (use stone foundations) etc. (see Chapter 5 of Building with
Bamboo by Jules J. A. Janssen);
preservation in the more narrow sense.
Before dealing with preservation we should first discuss the natural durability. This is lower
than for wood and in most cases it is too low for an economic lifetime. The lifetime of
untreated bamboo is:
in contact with atmosphere and soil: 1-3 years;
under cover: 4-6 years;
undercover and in a not very humid climate: 10-15 years.
Normally bamboo will be attacked by fungi (rot, only when moist) and insects (beetles and
termites). To avoid the last, bamboo has to be treated. Unfortunately it is quite difficult to
treat bamboo: the outside and inside are covered with a tight layer of cells, and the vessels
through which any liquid can enter the bamboo cover only about 10 per cent of the cross-
section of a culm.
The non-chemical or traditional methods will be discussed first, and then the chemical
methods. All procedures should be effective, safe and economic.
Traditional methods
The advantages of these methods are that they are very cheap and can be done without
special equipment.
Clump-curing The culms are cut, but left in place in a vertical position. The evaporation in
the leaves reduces the starch content and consequently beetle attack. However, attack by rot
and termites is not diminished.
Smoking The bamboo is stored above the fireplace. The smoke will blacken the culm and
might cause cracking too. The effect on durability is doubtful.
Soaking The culms are placed (immediately after the harvest) in water or mud with stones on
top of them to keep them down. They are left for several weeks and then dried over a full
week (in the shade, not in the sun!).
Seasoning Bamboo has to be dry. This is achieved by drying in the open, under cover, with as
much air movement as possible. It can take one or two months.
A general remark to end with: if the local population has a tradition of working with bamboo
they will know best the differences in natural durability between the several local bamboos as
well as the effectiveness of traditional treatments for various end uses.
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