I made this child's bow from a single piece of bamboo with a riser wired to the grip; inspired by Bhutanese technique. The arrows are also bamboo.
The single bamboo slat was merely heated very hot over a gas flame. Although it works quite nicely, I am wondering how the Bhutanese get such a nice dark color and if there is an advantage. Has anyone tried this?
jack farrell
The bamboo is Oldhami, now popular here. The poles are about 3 inches in diameter. My niece, at just 7 years is a total wimp and cannot pull a #100 bow so I had to make it about #15. The green set is for another lightweight neighbor.
I just know this will drive some folks crazy but whatever.
Has anyone baked(cooked) bamboo for bows? Have a formula?
jack farrell
Last Sunday.
Justin Ma
Geez, those youngin's are pretty spoiled to have a bowyer like you around.
jkekoni
Can you tell us the bow width, length and draw it gets 15# ?
I have wanted to make bhutanese bamboo bow so long time, but I have not been able to get suitable bamboo.
I have tried to back 10mm thick bamboo blanks with rawhide. It broke despite being low weight. I also made one from baboo bought from gardening store, it too broke despite being low weight.
Sinew backing could do better, but is no longer simple...
jack farrell
Jkekoni; Note that a Bhutanese bow has two pieces of bamboo wired to make a grip and mine has one with a riser wired as a grip.
The upper bow with red arrows; 36 mm wide just above the grip, 7mm thick there and 127 cm LOA., draws #14 at 22" (inches).
Bow with green arrows; 36 mm wide, 7mm thick, 127 cm LOA, draws #19 at 22". I know, both have the same dimensions but different draw weights.
The arrows are 26" all.
jkekoni
jack farrell wrote:
Note that a Bhutanese bow has two pieces of bamboo wired to make a grip and mine has one with a riser wired as a grip.
I know that. I did not mention it because it is hardly relevant.
It is just a way for making the bow construction easier. If the pieces are from same bamboo next to each other the bow practically tillers itself.
127 cm LOA., draws #14 at 22" (inches)
127 cm and 22" draw means draw ratio of 2.3. Quite normal for wooden bow. I think bamboo should do more.
You are not willing to risk drawing it to 26" ?
jack farrell
jk; These little archerss don't draw too far and besides, they are not my bows and I do not want to risk damaging them. I just gave a benchmark number.
jsachers
jkekoni; my Bhutanese bow is 160cm over all and draws roughly 60@26".
Just to give you another benchmark ;-)
jack farrell
I used to have one of those bows which came from India. They are also used there for folk archery contests. Seems like the bamboo was about 15 or 18 mm thick. There is no such thing growing here that I have seen.
It had been processed to a rich dark color and I would like to know how this was done. I assume it was cooked in a kind of oven or smoked, etc. It was bound together with wire and had tape covering the wire. So simple but effective.
mikekeswick
Can the belly not be heat treated with a heat gun - the same as wooden bows.
jack farrell
Mike; Please elaborate your technique.
jkekoni
I have used heat gun to heat treat bamboo backings for wooden bows *). I see no reason why it would not work on bamboo self bows.
I was thinking that in the reverse bamboo selfbow, the belly is likely to overpower the back. If you hat the belly it is more likely to do so. If you heat the back you make it more brittle.
This is all different from bow made from hard wood.
jsachers: That is more like what these things should be like. If I only could get such bamboo...
*) I do not generally recommend heat treating bamboo backings, since it makes them more britle and increases load in the belly wood, that is likely to be overpowered by bamboo anyway.
mikekeswick
What I meant was using a heat gun to heat the belly side of the bow or the outside (node side) of the bamboo depending on how you look at it!
The bamboo inner fibers (bows back) are strong enough in tension to handle the load, wether the belly is heat treated or not. Bamboo isn't too great in compression so heat treating the belly is the 'obvious' thing to do, essentially evening up it's tensile / compressive properties.
Virtually every 'white' wood self bow will benfit from heat treating, indeed it's something I do on my sinew backed wood bows most of the time.
For one of these bows I would heat the belly to medium brown whilst pulling the bow into a few inches of reflex on a form or by simply hanging a weight off the bow tip with the handle in a vice.
I am going to the best bamboo supplier in England tomorrow and will be on the look out for some thick walled stuff!
jack farrell
Mike; I have not previously heard of heat treating a wood bow. Live and learn.
mikekeswick
I've just been to the bamboo suppliers and they have some boo from Indonisian with walls over 1 inch thick!!! Overall diameter of around 12 inches and heavy.
They weren't sure what species it was, anybody got any ideas?
