Primitive Archer
Main Discussion Area => Bows => Topic started by: Bckskin2 on October 06, 2017, 06:31:14 am
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In the TBB volume IV, I believe, had some pictures and and a brief description of a Bhutanese bow. Does anyone have any experience with them? Are any of the PA advertisers a good source of boo? I can order from a couple of on line places, but I would have to order a lot.
Thanks,
Jerry
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Can't comment on Bhutanese bows but Carson at Echo Archery has quality Boo!
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There are several reputable sources that carry both planed and unplanned bamboo backing strips, but as far as bamboo as a core wood goes you will probably need to go to a big city lumber yard.
I've wondered if a person could use an engineered or composite bamboo plank and back it with a strip of bamboo or hickory...never been curious enough to try.
You might check out the Cali bamboo site, they offer 8 foot bamboo poles in bundles of 6 that are reasonable priced.
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There are several reputable sources that carry both planed and unplanned bamboo backing strips, but as far as bamboo as a core wood goes you will probably need to go to a big city lumber yard.
I've wondered if a person could use an engineered or composite bamboo plank and back it with a strip of bamboo or hickory...never been curious enough to try.
You might check out the Cali bamboo site, they offer 8 foot bamboo poles in bundles of 6 that are reasonable priced.
There was a member here in early 2000, can't remember his name now, that made a number of bows from Bamboo flooring backed with Bamboo. He claimed they were excellent performers
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It is unusual for bamboo to be bent backwards as the bows from Bhutan are and survive. Don't assume even good quality backing bamboo is up to that.
You'd need to source a similar type if not the exact one they use.
Back in the day "solid" bamboo bows made from strips were quite common and well regarded. Some of them were actually backed with Hickory too.
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I managed to make one that stayed together rather well, a few years back. It wasn't the best bamboo, and made cracking noises when first drawn, but it has survived being shot by many new starters at our field archery club, and still shoots well today. The only issue is that I wasn't able to get hold of any thicker bamboo slats, so even with a little heat treatment it was limited to around 25lb @28 inches draw weight.
I will add some pics if these links work:
https://flic.kr/p/qSNG7D (https://flic.kr/p/qSNG7D)
https://flic.kr/p/ra7BqK (https://flic.kr/p/ra7BqK)
Cheers, Bob
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I've written about this several times before, but I will mention it again. The traditional Bhutanese bow is a lap-spliced and bound pair of billets. The reason I believe they are doing this is to utilise the natural taper of the boo as it tapers from the base of the stalk up. I'd imagine this would make tillering very simple. The billets are bound with rope at the handle from what I have seen in videos of their traditional competitions. Perhaps some of them are also reversing the belly of the bow as this is a common enough practice in bamboo bow making. The MOST important thing would be to ID the species of boo they are using. Bamboo has well over 1,000 species and they all differ wildly. Simply getting some bamboo is a bad idea and likely a waste of time as there is a lot of bamboo in use commercially that is not going to be of use for a self bow. Although I don't know the species they use in Bhutan, your best bet is to find some Tonkin bamboo. It is at least on par if not better than what they are using and should be an acceptable substitute. Although the Bhutanese are currently using a lot of non-traditional bows, you can go to this website and ask them about some more information about the bamboo they are using. I am sure they would gladly help you out. http://www.baf.org.bt
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Thanks for the tips. I bet either of the sources that advertise in PA would OK
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The reason I believe they are doing this is to utilize the natural taper of the boo as it tapers from the base of the stalk up. I'd imagine this would make tillering very simple.
I should get two staves instead of cutting one in 1/2
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Actually two different bamboo have two different thickness, strength or length between the nodes. To have an even strength you need to use the same bamboo.
Get one with biggest diameter you can get and split them in two, then shave them down to size. However like everyone said, there is a huge variety of bamboo. Like in my country we got different types....some for food, utensil grade, furniture, blowpipe and bow.
In short....get two pieces from one bamboo and get the thickest and largest diameter bamboo you can find. You might not be able to get the best type for bow but it will be good enough.
Avoid ones with insect holes in them. Leave the nodes as the end part as they resist splitting. As for the species, I really can't help you. You can only get the best bamboo by harvesting and curing them yourself.
EDIT: The bigger diameter and thicker bamboo is fairly straight so you don't have to worry about problem with tapering or bending. A big bamboo strip section is also much flatter than a small one.
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Btw....anyone here from cold countries have problems with bamboo in freezing temperature? My old music teacher had problem when he does shows oversea because some of his instruments made from bamboo cracked in cold weather. We've discussed on materials to make the instruments and always have problem with tropical wood getting damaged in different environment.
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When I met John Strunk, he was working with bamboo as a backing and as a core. If I understood right, the core was laminated bamboo flooring, then he backed it with a regular bamboo laminate. He was very happy with the performance.
Sabb
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I managed to make one that stayed together rather well, a few years back.
Bob, Great looking bow. How wide at widest and tips?
https://flic.kr/p/qSNG7D (https://flic.kr/p/qSNG7D)
https://flic.kr/p/ra7BqK (https://flic.kr/p/ra7BqK)
Cheers, Bob
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Another thing you can try is to get two bamboo strips and laminate them together after heat treating the belly lam thoroughly. This allows you to get the dense outer cortex of the bamboo for both the back and the belly, the heat treating reduces set (which is terrible in bamboo) and it allows you to glue in reflex as well or simply bend it to whatever shape you are looking for. Not the Bhutanese method, but makes a good bow this way.
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Limbit, What kind of glue would you use? I had also though of a cordage boo. but have trouble finding silk string.
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the butanese use a special type of very strong bamboo apparently, without this the bow wouldnt be very good....there are many types of bamboo...the common moso isnt strong enough to make an efficient bow with this method IMO, i have experimented with this....it would still make a bow this way tho. most boo bends equally well both ways and the harder outside layer is better in compression, so this method makes sense.....without this type of boo its better to use the boo as a backing or to use laminations of boo
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Like I mentioned before, I doubt the boo they are using is much better or worse than Tonkin and this could be the best solution to the problem of what type of boo to use.
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Tonkin doesn't handle a backward bend well.
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Tonkins walls are generally relatively thin. The diameter of the poles wouldn't be big enough to get flat enough strips either, the backs edges would likely fail.
Tonkin is a wonderful material and if you weren't set on a particular style then as mentioned above using a heat treated belly lam and a backing lam both with the boos outer surface as the working surface is a good way to go.
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Yes, Tonkin is very thin walled, that is why I mentioned before to take the boo from the lowest part of the stalk where the walls are thickest, split it and lap-splice it at the handle allowing a natural taper and enough thickness. Of course you would need to harvest it yourself since I doubt companies sell poles with the base. I guess you could potentially use a sort of HLD design as well and use a goose-neck scrapper to tiller it following the natural curve in the boo. I am still curious what bamboo they use. Bhutan has such drastic changes in climate since it is a mountainous country. It could be the boo is coming from higher elevations and is some sort of large slow-growing variety. From pictures I've seen, the boo is a thick-walled variety so I am guessing it is a large diameter.
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Yes large diameter and very thick walls are prerequisite for this style of bow.
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I managed to make one that stayed together rather well, a few years back.
Bob, Great looking bow. How wide at widest and tips?
https://flic.kr/p/qSNG7D (https://flic.kr/p/qSNG7D)
https://flic.kr/p/ra7BqK (https://flic.kr/p/ra7BqK)
Cheers, Bob
Ok, i have made a few photos of the bow to give you some clues :) sorry the details are in metric but that was the only ruler i could find quickly. The bow is 176 cm from nock to nock. Here are links to the pics:
(https://farm5.staticflickr.com/4456/37795624011_8abfcf4ac4_z.jpg)
(https://farm5.staticflickr.com/4488/23942790178_f9132dda10_z.jpg)
(https://farm5.staticflickr.com/4467/37795623011_6475372927_z.jpg)
(https://farm5.staticflickr.com/4455/37125522923_88da5ae5da_z.jpg)
(https://farm5.staticflickr.com/4508/37763824842_e82c6be002_z.jpg)
(https://farm5.staticflickr.com/4477/37763823612_d6910db237_z.jpg)
The resting bow has the nocks in front of the handle - i heat treated the bamboo over a form and the change has remained well over the years of being shot. As usual for these bows, the outside of the bamboo is on the belly of the bow. The two pieces of bamboo are located by japanese style pegs, and then the ends of the pieces were wrapped in rawhide soaked in glue. As the glue dried the pieces were pulled together very tightly.
Cheers, Bob
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Looks good Bob! Do you know which species of boo you used? Looks like Moso. I've used it laminated several times and heat treated and it seems to hold its form well after heat treatment.
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Looks good Bob! Do you know which species of boo you used? Looks like Moso. I've used it laminated several times and heat treated and it seems to hold its form well after heat treatment.
I'm afraid i couldnt say for sure, asi made the bow a few years back now but it would be a commonly available type. This bow was a bit of an experiment but it worked well, and is quite simple to try out. If i could get my hands on some thicker, denser boo then i would make a higher draw weight bow, as this design shoots extremely well, with zero handshock.
Cheers, Bob