bamboo backing length

[arachnid]

Hi Guy.
I have a question about bamboo backing.
As we all know, composite bows are made shorter the wood bows.
Does bamboo work the same? If I make a BBI, could I make it shorter then a regular
board bow?
If so, what is the minimal length for a safe to shoot BBI?

Thanks in advance.

Dor

[DarkSoul]

A bamboo backed bow can in general be shorter than a selfbow. Bamboo can bend really far before it breaks. However, the belly must also be able to resist the sharp bend. A bamboo backed balsa bow could not be made any shorter than a balsa selfbow, because the balsa would be the limiting factor. The balsa would fail in compression long before the bamboo would in tension.
The minimal safe length of a bamboo backed ipé (BBI) depends on many factors, such as draw weight, draw length, limb width, stiff handle yes or no etc. The shortest BBI I've seen and shot was (I think) 58" NTN, stiff handle, R/D design, about 1˝" wide, 65#@28". In my opinion, this bow was underbuild. But it held up, and goes to show how much a BBI can take. Lowering the draw weight to 50 pounds would have made that particular bow much safer. I'm sure a bend-through-handle bow could be made even shorter, and 56" for a 28" draw length should not be a problem if designed properly.

[WhitefeatherFout]

Make sure you thin your bamboo or you'll run into problems, even with Ipe.  I would recommend cutting out the profile of your boo first and then thin it to no more than 1/8" at the handle and taper it to the tips.

[Pat B]

James Parker has built a few Asiatic horn bows without horn but tempered bamboo belly. These guys are pretty short.  Check out James' website, Huntworthyproductions. There is probably pics of these bows on there.

[Badger]

  I make all mine the same length I make a self bow or any laminated bow. I have never heard they should be shorter? Right now most of mine are 65 to 66 long.

[Eric Krewson]

Short bows tend to be a little squirrelly  to shoot so I make my BBOs about the same length as a selfbow.
 62" for a 25" draw or less, 64" for 25" to 28" draw, 66" for a 29" to 30" draw and 68" for draw lengths  over 30". My finding is BBOs don't hold up for long draw lengths unless the bow has added length, the bamboo will tend to splinter on the back if over drawn.

[adb]

Hi Guy.
I have a question about bamboo backing.
As we all know, composite bows are made shorter the wood bows.
Does bamboo work the same? If I make a BBI, could I make it shorter then a regular
board bow?
If so, what is the minimal length for a safe to shoot BBI?

Thanks in advance.

Dor

Huh? Since when? Whether backed board bow or selfbow, the length of the bow has to match the design and intended outcome. I would really like to dispel some of these mistruths about bows. Where do those statements come from, and why do people blindly accept them?

[PatM]

I'm surprised so many experienced guys are questioning this. There are many examples of short Ipe/boo bows that  are far shorter than the recommended dimensions for a typical wood bow.
 You can find several 54-58 inch examples  on here or PP that are drawn 26- even 30 inches. The extreme tensile and compressive strengths of the materials allow them to be maxed out further than more delicate materials.
 
This bow by Rich Saffold is a great example of the possibilities.
  http://paleoplanet69529.yuku.com/topic/5622/Latest-Ipeboo-bow

 Here is a pic of an Ash backed  Ipe short bow that is just 54" and only popped a splinter at 28" as I tested the limits.

[Badger]

  Pat, I am not questioning that it can be shorter, I make them as short as 40". I am questioning that they should be shorter. Bamboo has the ability to make a short bow no doubt. I don't think anyone questioned the ability of boo to make short bows. It performs well in any design.

[arachnid]

Hi Guy.
I have a question about bamboo backing.
As we all know, composite bows are made shorter the wood bows.
Does bamboo work the same? If I make a BBI, could I make it shorter then a regular
board bow?
If so, what is the minimal length for a safe to shoot BBI?

Thanks in advance.

Dor

Huh? Since when? Whether backed board bow or selfbow, the length of the bow has to match the design and intended outcome. I would really like to dispel some of these mistruths about bows. Where do those statements come from, and why do people blindly accept them?

7

Well, as far as Iknow, the whole idea of a composite bow (sinew, horn etc.) is to make it shorter (so it can be shot from horse backs).

[Marc St Louis]

Bamboo is strong in tension but it will lift a splinter if stressed too much.  I tend to make them the same length as a bow made from tension strong wood, Elm, HHB.  I've had Bamboo pull a splinter before and it's not fun.