How to heat treat bamboo

[chappie]

Hey guys,

I wanted to make a bow with a bamboo back and belly and i thought i had figured everything out, except i learned that it was wise to heat treat/temper bamboo. I wanted to know if there was a difference between heat treating and tempering and if/how i could achieve it by using fire/a heat gun/oven?

[Pat B]

Chappy, only the belly boo gets tempered. It increases the compression strength but it has to be done before glue up. Do not temper the back boo piece. Plus you have to pre-engineer all components because once it's glued together very little tillering or weight reduction can be done.
 I watched James Parker temper boo for one of his boo backed/belly bows. He used a rosebud propane torch to temper it. To me, it looked like he was completely burning the boo up. As he passed over the boo with the torch you could see the totally carbonized boo surface and the heat wave in front of the torch was quite visible. It was actually scary to watch. James has made hundreds of these bows so I know he knows what he's doing.
 You might find a YouTube video with the process. A few folks on here have made boo back/belly bows so someone should be able to help you through the process.

[bjrogg]

I wish I could help you. But I have zero experience with boo.

I could see Pat was replying and I had to see what he said.  Very interesting Pat. I was pretty sure you would just want to heat belly.

I was pretty sure before glue up.

I was surprised by the rosebud on the torch though. I’d like to watch that.

Bjrogg

[Pat B]

BJ, I wish James would come on and post pics of his tempering process. You would be surprised. He may have a You Tube video with the process but I don't know.

[dylanholderman]

From what you described pat that sounds similar to videos I’ve seen of guys making bamboo fishing poles

[Eric Krewson]

10 years or so ago a guy in Texas was selling what he called tonkin cane slats, I bought some. In my opinion it was actually mosa that had been heat treated back and belly, the nodes had been charred in the process, the slats were chocolate brown. The slats were flat and 2 1/2" wide, real tonkin doesn't grow big enough to make a 2" wide flat slat.

The first I bought was great stuff and made great performing BBOs, the next was garbage, as his stock ran out he started sending out cracked and split stuff.

[chappie]

Thanks everybody for the fast replies.
I indeed know that only the belly needs heat treating, also i figured out the tillering part so i hope i won't have to much trouble with that.
The reason i was asking it here instead of watching some youtube video's is that a lot of the video's on youtube are not on bamboo for making bows and i wanted to be sure that what i was doing was good for a belly.

I found this article (https://jwoodscience.springeropen.com/articles/10.1007/s10086-016-1574-3#:~:text=Mechanical%20property%20of%20heat%2Dtreated,of%20the%20sample%20%5B35%5D.) This article says the mechanical property starts to decrease at 150 degrees celius and improves at a range of 110-140 degrees celcius. I wanted to know what u guys thougt about this and if it was correct how long i should heat the bamboo to this temperature?

also should i temper it on the inside or outside of the belly?

[Pat B]

You want to taper the inside of the boo. The power fibers are along the outside, under the rind.
 I can't help with what temp to treat it to.