Bow from only bamboo?

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Cikoun

New Member
Feb 22, 2021
3
0
20
Czech republic
Hello everyone, I would like to make my first bow and would appriciate some advice. I was thinking about buying a board and making a board bow but since all the DIY stores sell goods only online (I live in the Czech Republic) I am not able to choose the perfect board with straight growth rings personally. Therefore I decided to buy a thick bamboo log but haven’t found much about making a bow purely from bamboo. I’d like to ask you if it is even possible and if it would hold the shape and poundage. my goal is somewhere around 30 pounds. Also is there an option of buing board online (with random growth rings) and use it as belly or do the growth rings really strictly need to be straight as it is with the backing?
With Thanks
Filip
 

C_Claycomb

Mod
Mod
Oct 6, 2003
6,377
1,344
Bedfordshire
Hello and welcome to the forum.

Ignore Erbswurst ;)

While there are some archers and bowyers here, I think you will make more progress with a dedicated archery forum. There was recently a thread that talked quite a lot about bow making and information resources.

There are links to some really good dedicated bow forums in the thread above.

Wayne, one of the other moderators here teaches building bows from bamboo at our summer Moot gathering. Another Mod put together an article for his Blog - building a bhutanese bow

You can get away with a lot of board imperfections if you glue a backing material to the wood. One of the best is linen in its raw fibre form, but you can use linen cloth. You can find threads about linen backing board bows. You can use other things to back bows, like rawhide, and bamboo, although bamboo is so strong in tension that it can cause the belly wood side to crush, so not recommended just yet.
 

C_Claycomb

Mod
Mod
Oct 6, 2003
6,377
1,344
Bedfordshire
 

Erbswurst

Bushcrafter (boy, I've got a lot to say!)
Mar 5, 2018
2,535
979
Berlin
OK.
I admit, that I am not from Bhutan.

As long as we were shooting with yew tree bows our armies had been successful.
 

C_Claycomb

Mod
Mod
Oct 6, 2003
6,377
1,344
Bedfordshire
Growth ring orientation is less a problem than wood fibre direction. The back of the bow does not need to align with the growth rings, as it would if you were using a tree-split stave, but if the wood fibres run through back-belly at too much of an angle, the bow will tend to want to split. Backing can help with this.


What kind of wood are you looking at using?

Chris
 
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C_Claycomb

Mod
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Oct 6, 2003
6,377
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Bamboo doesn't have growth rings. The modulus of elasticity may be too low for a bow, but it works just fine as 6 thin slivers glued up as a "split cane" fishing rod.

These people have very extensive forums and archives on bow building:
https://www.tapatalk.com/groups/paleoplanet69529/
Could you please check your figures on elastic modulus and define what range you think is good for a bow?

The ones I have seen show "premium" bow woods as:
Hickory - 14.9GPa
Osage - 11.6GPa
European Ash - 12.3GPa
Pacific Yew - 9.3GPa
and
Bamboo - 18GPa

While bamboo can make awesome laminated bows, that is likely a bit much for someone's first bow.
 

Robson Valley

Full Member
Nov 24, 2014
8,878
1,791
McBride, BC
I left all my textbooks and references behind for the next fool that had to spend a decade teaching dendrology. I might have got it bass-ackward.
Is there anything applicable in The Wood Data Base on line?

Hickory (Carya sp) and Ash (Fraxinus sp) are both ring porous. The staves can be oriented in the manner of leaf springs. There are some First Nations bows in museum collections in Western Canada that show this.
My brother belonged to a group building bows and arrows in conjunction with a group of flint knappers. That was my introduction to the value of the correct orientation of the wood. Locally, the arrow shafts were Saskatoon (Amelanchier alnifolia) and Chokecherry (Prunus virginiana.)
 

C_Claycomb

Mod
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Oct 6, 2003
6,377
1,344
Bedfordshire
It was the online Wood Database that I looked at second. While its pretty good for tree wood, the possible variation in bamboo leaves makes me cautious about that one figure , but it seems indicative at any rate.

My understanding is that the problem with using bamboo for a whole bow is more about its shape/size, effect of the nodes, and its nature to be a little splintery. The material I have read about using it in bows says that when used as backing its stiffness, relative to most woods, can lead to it overpowering the belly wood and causing frets, compression fractures. Despite this, I have seen photos of some very nice osage bows with bamboo backing, just done quite thin. Hickory is recommended as a better match.

Just found this, which is an interesting idea. Uses a bamboo laminated flooring board!

Re the leaf spring arrangement. Was that like the Penobscot bow?
 

TLM

Native
Nov 16, 2019
1,604
703
Vantaa, Finland
While elastic modulus is important, more so is strain to failure. Modulus can easily be compensated by cross section but low breaking strain leads to impractical bows.

Good bamboo is one of the better materials for making.
 
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eraaij

Full Member
Feb 18, 2004
519
24
Arnhem
Yes - I made numerous quick bamboo bows by wrapping these garden staves together to desired strength. You can even 'prototype this by using duct tape. Just experiment with it.

They are fun shooters but tend to develop a 'set' over time. However - as lamination material you see it used a lot.
 

TLM

Native
Nov 16, 2019
1,604
703
Vantaa, Finland
The neutral axis for bending has to be calculated modulus weighted. As high modulus material bamboo tends to move the axis its way causing more strain on the otheer surface.
 
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TLM

Native
Nov 16, 2019
1,604
703
Vantaa, Finland
Bamboo-osage bows apparently work quite well, several bowyers here have tried it with fair success. The bord showing them is only in Finnish though. Bamboo from various sourrces in Asia and osage fron Hungary.
 
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Broch

Full Member
Jan 18, 2009
4,530
3,804
Mid Wales
And yet we made very serviceable and fun bamboo bows when we were kids in North Africa without any of the theory. I'm talking real bamboo mind, more like small tree trunks than canes (50mm to 75mm diameter). No science, no modulus of elasticity, no worries about stress or strain - just have a go and enjoy it. It's horrible stuff to work though and we had loads of cuts from the edges.

OK, to be fair we were shown how to do it by the Arab kids, who no doubt learnt it from their fathers, but there was no 'exactness' to it and they were very useable bows. There are loads of Youtube videos that will show you a variety of ways - from the simple to the complex. It's not at all difficult to get a 20lb+ bow with the right material though the faster ones were usually heat treated.

Edit: I should confess, I haven't made a bamboo bow for a very long time mind; we just can't get that quality of material here.
 

bobnewboy

Native
Jul 2, 2014
1,022
464
North West Somerset
You can make a simple but effective 'Bhutanese' type bow with two pieces of bamboo, joined at the handle. No backing is necessary, but it is a good idea to reinforce the bow nocks to avoid string wear and any chance of splitting the limbs. The draw weight depends very much on the thickness of the bamboo that you can get. You can also directly increase performance of the bow by heat treating the limbs once made, using a heat gun like those used for paint stripping. I made a bow of this type many years back, and it is still working fine. I posted a few pictures of it on Primitive Archer, see my posts in the following link: Primitive archer post

Edit: I forgot to add, in this type of bow the inside surface of the bamboo makes up the back of the bow. That is counterintuitive, but works well. I have handled a proper Bhutanese bow, which was made from bamboo which had more than a half inch thick (12mm) wall, and pulled upwards of 50lb draw weight. With reed-based arrows the performance was extremely good.

I would also strongly recommend Primitive Archer forum for detailed information. It is a US-based forum, but very knowledgeable and helpful.

Cheers, Bob
 
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