Heat Treating Bamboo

Posted: 11th June 2010 by Nigel in Bamboo Bike, Working with Bamboo

Heat treating is an important process for preparing bamboo. Essentially it removes a lot of the moisture, making the poles lighter, and most importantly it cooks the sugars in the shoots. Bamboo is a species of grass, much like sugar cane, and is full of sugars. When these sugars are cooked, they turn from being a thin liquid to becoming hard, much like the process of turning maple sap into maple candy. The hardening of the sugars binds the fibres in the shoot, creating a very strong tube. If you think this sounds familiar, it is because it is. The same process is used with pre-impregnated carbon fibre, basically making bamboo nature’s composite.

The process I used was recommended by a few different people who have provided online tutorials on bamboo. See this tutorial for an overview and this forum for a wealth of knowledge on all things bamboo.

EDIT: for a video of this process, check out this post.

  1. Use fresh bamboo, as green as possible. Cut it to lengths that are a little longer than you need right before you heat treat, being careful not to split the bamboo.
  2. If the section is long enough that there are more than two nodes, drill them out. Otherwise the pressure in the sealed centre section will make the piece explode.
  3. Use a regular pencil blowtorch, and start with a quick once over. The goal is to draw out the wax and oils and wipe them off with a lint-free cloth. Heat the piece section by section, hot enough that there is visible bubbling on the surface, but no discolouration. Then wipe off the oil and wax before it is reabsorbed.
  4. With a slow, steady typewriter-style motion, heat the bamboo to a yellowish colour. The torch should be about 5-10cm from the bamboo. If you burn a few sections, don’t worry. Keep moving, and you will come back to darken the whole thing again in the next step.
  5. Allow the section to cool, and then go over it again. This time you will bring it to your desired colour. I went with a mid to dark brown. You can go anywhere from very light brown to almost black. If you go too dark, or you burn a section, you can sand it later and it will expose lighter wood underneath.
  6. Seal the wood with something. I used pure beeswax, but you could use any kind of wood sealer. To seal with beeswax, rub the bamboo down when it is still hot, then wipe off the excess with a lint-free cloth.

I will post a video in a couple days.