Bamboo backed bamboo.

[wood carver 2]

A while back we were talking about boo backed boo bows. I started working on one today and I was wondering how thick the boo back and belly need to be. the piece I chose for my back is about 5/16" thick in the middle and I'm thinking of tapering it to the tips. The belly lam is about 1/4" thick and going to be tapered as well. I'm also planning to heat treat the belly. Would heat treating the back give any benefits?The riser is 1 3/8" wide and 15" from fadeout to fadeout. I'm not sure how long to make it though. I'd like it to be in the 50# to 60# range. Also, should I use a mid lam or a power lam?
Thanks for any input.
Dave.

[Pat B]

Dave, are you using the outside(power fibers) of the boo for both the back and the belly? Boo backibng should be 1/8" thick at the crown at the handle and can be parallel to the tip or taper in thickness so the tip is 1/16" thick. The belly, if using a boo backing strip for the belly, should be identical to the backing but should be tempered to hold up to the compression stresses. Do not temper the backing strip. It will make it brittle and lesson the tension strength.

[wood carver 2]

Pat, I am using a backing strip for the belly lam as well as the back. Would I be able to build a hunting weight bow with only two 1/8" bamboo lams or would I need a mid lam?
Dave.

[Pat B]

You'll need a mid lam(s) to get to hunting weight. You will have to pre tiller the mid lam because you can only tiller from the sides on a boo backed and belly bow once glued up.
  I have 2 boo backed and belly bows, one is a "Cane Dragon" by Vinson Minor(mild R/D design), it is 66"t/t, pulls 53#@28" and is 1 3/8" wide at the fades with a thickness taper of the core wood(osage and maple vertical lams)that is 7/16" at the handle(instead of an added power lam) then at the fades it is 3/8" and tapers to 1/4" at the tips.
 The other was made by David Knight(medium R/D design)and pulls about 45#@26". It is 60"t/t about 1 1/4" wide at the fades. It's core is solid ipe that tapers from 3/8" in the handle to 1/8" at the tips. This bow does have a power lam above and below the core.

[wood carver 2]

Thank you Pat. With this information I should be able to build a bow.
Wish me luck. Out of my last four builds, one exploded, two developed hinges and the one shooter came in well underweight.
Dave.

[Pat B]

Maybe #5 will be the one!  Take it slow and easy!

[wood carver 2]

   

[SEMO_HUNTER]

I had to put my boo on boo project aside for now, life gets in the way sometimes. If you go without a core lam the boo will need to be thicker to make wt. than it would be if you just used it as a backing. With back fibers and nodes intact on the back and belly I'm going with 1/4" on each piece of boo at the fades then tapering down to 3/16" mid limb, then 1/8" at the tips. That would give me an overall limb thickness of 1/2" at fades, 3/8" mid limb, 1/4" at the tips, hopefully that along with my limb profile will yeild something between 50-60#

I doubt that I will get back to working on it till after turkey season is over. Unless of course I check 2 birds by the 2nd weekend, but that rarely happens around here.

[PEL]

I am also starting a boo-boo bow.  I just blew up one with a vertical bamboo plywood core - just the worst glue up ever!  
     I was planning to use a straight taper profile from 1.5 inches at the fades to 1/4 inch at the tips - would this work with Semo's thicknesses?  comments please

[PEL]

Oh Yeah - I am planning on around 64 inches.

[wood carver 2]

Turkey season is a great reason to put everything else on hold Chris.    
How wide are your limbs going to be? I was thinking 1 1/4" or 1 1/2" tapering to 3/8" and I might add a very thin centre lam to add color.
Dave.