Fire curing bamboo (bonfire)

[saxofoner]

I have recently been curing bamboo over a fire built in a fire pit outside. It works well, except that the steam build up inside is so great that the interodes practically explode after 5 min.s of heating. Drilling tiny steam holes works perfectly, but I was wondering if anyone knew how to prevent the "pop" without altering the bamboos surface.
i.e. does holding it at a farther distance from the flame help?

thx n advance

[Mark Meckes]

Ahh yes, fond memories of the good ole days living in the countryside and open pit bamboo curing. Now I live in a city where open fires are not allowed, except for bar-b-que grills.
The objective in `flame-curing' bamboo is primarily to serve as a pre-cure, that is, not to totally dry out the bamboo. That must be allowed to happen more slowly.
The main objective is to draw out and wipe off excessive waxes and oils, relax any tension in the bamboo, change the color of the bamboo, and upon cooling, the bamboo surface hardens which can make the bamboo more resistant to splitting.
This procedure works best with green bamboo or bamboo that has not been thoroughly dried, because the bamboo is more elastic, and the water content in the bamboo will prevent the bamboo from becoming charred.

This requires quick work, rotating the bamboo, so that all parts become evenly heated. At first the surface will be sticky. At a certain point the exudate will become slippery. Then a rag is used to wipe off the excess exudate. Bees wax can be rubbed on to the bamboo, or a paste wax can be applied to the cloth, which acts as a solvent helping to remove the exudate, which will quickly become sticky again as the bamboo piece cools.

This is hot work requiring fast and attentative action!
If the fire is smokey, carbonized soot will adhere to the sticky surface of the bamboo. This can be wiped off at first wipe, but putting the piece back over the fire can cause carbonized staining of the bamboo - good or bad, depending on your tastes.
If the bamboo POPs , you've heated the bamboo too much. This much heat isn't necessary or adviseable.
In some scenerios, especially whn bending bamboo and wanting to keep the bent shape, the bamboo can be dipped in water to cool the piece, which will help to `set' the bamboo. It's also a method to further heat the bamboo without burning it.
Also spritzing bamboo with water during the heating process adds some interesting effects to the bamboo.

Nowadays I prefer to use a gas (propane) torch to heat treat bamboo, because it provides me with much more instant and directional control, though regrettably I now have to purchase this heat source.

What kind of bamboo are you curing? Locally grown green, or imported dry bamboo?

Mark

[manoz]

i remember when mine first exploded.........i still use the firepit myself but a few different ways......first i heat directly over flame just to heat it up ......i'm always moving toward straightening the bamboo out so i have pegs in the ground

then i take bakers pans,get red hot coal from the middle of the fire place in pan, i then put the pans of coal under the bamboo and let it heat up real good,i move along down the bamboo until the whole thing is heated....remove the coal afer that and i let it cool in place when its cold to the touch i remove it and it stays straight.....i have straightened 8 footers like this ........the heat is more controlled........no soot from flame......just my experience......thought it might help

[saxofoner]

Thanks much, to both of you for your ideas. I haven't experimented much w/ this method, but I will try that thing with the pan of coals.

[Mark Meckes]

Good point about using hot coals for relatively smoke free and better control of heat tempering bamboo.
The problem I had using a fire for this purpose, was that the fire was often created to prepare my dinner at the end of the day... by the time the fire /embers were nice and hot and supper was consumed ,I would be pooped, tired, done in for the day, and not up to stoking the fire for another round of bamboo.
Having a `burn day' was a different story, though hot work!
Different strokes for different folks under differing conditions.
I like the instant On/Off use of my propane torch now... will write about it in a separate thread soon...

Here's some pics posted by huntergather, on straightening bamboo poles, and I'm sure he'll be writing more about these pics & process used soon.

http://www.bamboocraft.net/workshop/data/508/thumbs/Bamboo_Tools_-_Heat_and_Bend.jpg See photo (http://www.bamboocraft.net/workshop/showphoto.php?photo=1281) http://www.bamboocraft.net/workshop/data/508/thumbs/Bamboo_Tools_-_Bending.jpg See photo (http://www.bamboocraft.net/workshop/showphoto.php?photo=1282) http://www.bamboocraft.net/workshop/data/508/thumbs/Bamboo_Tools_-_Bending_Grip.jpg See photo (http://www.bamboocraft.net/workshop/showphoto.php?photo=1283)