How to Fire Harden Bamboo

Bamboo has a naturally hard outer shell, and the inside can be hardened with fire.

Bamboo has long been used to form spears, fishing rods, musical instruments and other materials vital to human life. For bamboo to last, or to become sharp to use for a tool or weapon, it must be fire hardened to strengthen it.

1. Cut the piece of bamboo to the length that you need it for your project. Use a hatchet or saw to cut the piece to length. Remember that bamboo is hollow inside, so it often requires less work to cut than other wood.

2. Shape the bamboo piece from the inside out. If you intend to whittle it down to form a mouthpiece, spear point or other shape, use a knife to carve from the inside out. Bamboo is naturally hardest on the outside, so you will shape and then harden the inside to reinforce this already-hard outer layer.

3. Hold the bamboo perpendicular to flame; harden only the inside of the bamboo stick. If you have a handheld lighter or torch, this can be easier, since you can direct the flame more easily.

4. Direct the flame or position the bamboo so the flames are lightly licking the interior of the bamboo. Don't let it catch fire. If it does, blow it out immediately.

5. Run the flames over the interior of the bamboo until it is slightly charred; it will take on a dark brown or black appearance. Allow it to cool and test the inside with your fingers; you should feel a uniform hardness. Bang the exterior against something hard in multiple places to test the strength. Apply additional heat to weaker areas as necessary.

Warning

Unless you are a professional, do not rely on fire-hardened bamboo for any dangerous tasks. This process takes a lot of practice to perfect.

Check out this related video from Homesteady on Youtube.