Questions about bamboo used in archery

[Elison]

Hi guys!
I have a lot of questions about bamboo used in archery.
So, be patience with me...          

First of all, as we know, the bamboo can be used:
- in the backing of a bow, laminated with some kind of wood;
- in core-lams, laminated with fiberglass;
- in the belly of a bow;

but each of these uses has some particularity.

Some species of bamboo works better in a part than in another.

So,
 
1 - what kind of bamboo is more recomendad for example, to the backing of a bow?
I have used the 'Moso bamboo' and the 'Gigants' and I had good results.
For other side, I tried to use the gigants as core wood, and the bow broken in the knot.

2 - I learned that we shouldn't remove the external part of bamboo ( the smooth part) in the backing, but some bowyers do it ( or at least seems to do ), for example:

       

In the video, the bamboo is almost white, aparently had the smooth part removed...  or is different specie of bamboo.

3 - in the belly is same thing... some bowyers use to remove it:

       

     

What's the "magic"  in both cases?

4 - In core lams, whats the proper specie to use? Can be used the Moso bamboo? The tonkin cane is famous, but difficult to find. I heard he has continuous fibers in the knots...  

5 - There is some advantage using treated bamboo?


I think for now is it. =)
thanks all guys!

[Pat B]

Because bamboo is very strong in tension it makes a great bow backing. To use it as a belly it first needs to be tempered to increase it's compression strength. You do not want to use tempered boo as a backing.

[Nezwin]

G'Day Elison,

1. I've got some Moso bamboo at home, which I understand to be one of the 'tougher' bamboo species. For the most part though, the pole bamboo we get here in Australia is much of a muchness, really (that means, fairly similar). For a backing, I think that pole bamboo is pole bamboo, I don't know if in archery applications the difference between species makes a huge change in it's use. It's probably more important that it's a wide enough pole not to have a high crown, which is why Tonkin might not be appropriate for backing.

2. I think removing the outer layer of the bamboo is by preference. I have a Sam Harper bow where he has removed most of the outer 'rind' (rind, in english, is the same name as the skin on an orange fruit) while I've seen other bowyers keep the back of the bamboo untouched.

3. I don't know if there's a big difference, as point 2.

4. The Japanese bows make a huge deal out of multi-part laminates in their cores. For most people making standard bows, I don't think it makes a big difference. There's far more variables to consider beyond the species of bamboo in the core - it would ultimately make a very small difference in the performance of the bow.

5. As per Pat. B's response, heat treating bamboo on the belly increases its compression strength. You wouldn't heat treat a bamboo backing.

Hope that helps!

Neil

[KenH]

I make bamboo self bows and Magyar style slightly reflexed bows with glued and bound rigid siyahs, using the rounded natural side of the culm as the belly, and the flattened inside of the culm as the back of the bow.  I do heat treat the belly on occasion but usually tiller the draw weight by removing thickness from the back.

[inksoup]

i wish we could have naturally grown bamboos here in tr...

[Elison]

Nezwin, I'm curious about the bow.  Can you take some pictures for me, please?

I've read too many times the build-alongs that Sam made, but I always thought that the rind is a superior layer, above the bamboo fibers and the smooth part.

When I make a bamboo backed bow I remove the fist layer ( like a dry wax who pulls of when I rasp). But below this layer has another one smooth and very clean ( I dont remove that ), and only in the third layer is the bamboo fibers.

I have some pictures...  take a look...  

Original bamboo:
     

     

First layer removed:
     

   
 
In these pictures we can see in the contorn of handle overlay a part of first layer...

Then, below the second layer, we got the bamboo fibers:
     

When you and Sam says "the rind", that means the first and the second layers?

Both could be removed without any problem?

Other thing I remember now, about the bamboo flooring...
Bamboo flooring is made with bamboo fibers, and I have saw some bows made using it in the belly of the bow, but I was wondering if it could be use in backing too.

Thank you very much guys! =)

[M60gunner]

would not leaving the enamel (rind) on make it harder to apply a finish? Do some bowyers consider that a finish and just polish it? That would mean an absolute clean piece of bamboo. Heat treating is used to remove moisture as well as heat treat the power fibers. How do you get out the moisture otherwise?

[Elison]

Removing the first layer I'd have no problems to apply a finish...  

Example:

* Tung Oil + waxy shellac:
 

[Nezwin]

http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=011880

This is the bow I was fortunate enough to buy from Sam. It's a superb shooter, one of my favourite bows.

The rind is as you described, the first two layers. I sand it off myself, which also takes the nodes down too. I'll get some pictures of a few bows I've built & post it.

Neil