Question about Osage and bamboo?? And bow build

[Selfbowman]

I used two cauls on the bow. One had bigger recurves on the end and I am limited on width  so I went with less recurve and more Perry reflex in the middle. Now I have to make another caul for when I glue the bamboo on.

[superdav95]

I’m joining the party late but my experience with bamboo as a backing is that it will overpower your belly wood if not careful to get it very thin and tapered well.  I built a bunch of these boo backed bows and all of the best ones that survived had a very thin boo backings. Your record bow is awesome but I believe it would be even more awesome and would have survived possibly with thinner boo strip on the back.   The last few I’ve done like this I built the base bow (non backed) looking good at 20”draw and got it to about 30-35lbs projected draw at projected desired draw length. Estimated of course but pretty close.  Then I got to work with my backing and got the handle area thickness around .012-.013” and then tapered down to .090” mid limb and then a bit more to about .085” if not a stiff tipped bow.  If doing a stiff tipped bow or flipped tips I’ll increase thickness to about .090-.095” with a gradual taper from the mid limb.   The boo strip is also given a heat treatment/temper on the flesh side only.  I basically go till I get the rind side shiny and sweating slightly.  It will color change the flesh side too to a light brown.   It will swell a little if you do it right requiring you to reflatten before glue up.  I plan to do an Osage boo backed here soon myself actually.   I know Simk offered you a slat but I’ve also got some of the shipping from his location is prohibitive.   I’ve got a couple threads on here over the last few years that go through a build along if you need more details.   Just call me anytime too which works.  I’ve made a number of these and they are great bows.  Boo is very very tough!  And if heat treated is very hard.  I’ve yet to have a boo backed bow fail in tension.  It’s always the compression side that fails.   It’s a fun project and can’t wait to see what comes of this.  Reach out any time.   Dave. 

[Selfbowman]

Dave let’s talk mass here. This is when we need the mass theory guy. I’m going to weigh my record boo backed bow and compare the  mass weight to my build. I know that about 3 oz come out in my handles. I’m treading water here that’s not been there before to my knowledge. This combo of boo and Osage has so many unknowns and limitations in tiller so I’m guessing on thickness of laminates in the limbs. Interesting I keep hearing that!! Interesting does not help me guys.🤠🤠🤠

[Selfbowman]

Off the caul . Looks pretty good.

[Selfbowman]

Balance point pretty close.

[Selfbowman]

New caul for glue up

[Bob Barnes]

This is one of the best experiments that I've seen in a while.  Thanks.  I do agree with Dave about bamboo being much better when as thin as possible...as backing.  I try to do about 1/8" thickness even though it requires getting very thin on the edges if the bamboo isn't really flat/large diameter stuff.  It would seem like using it for a belly would be the same.  Good luck...this will be great.   

[superdav95]

Hey Arvin I suspect that if you get that book strip nice a thin with good taper on both limbs and glue that to this ideal growth ring Osage you will have no issues with the tiller.  If you can get good glue up and heat treat that boo strip you will have a winner I believe.   Just my opinion.  As for the mass of your use a thinner boo slat to utilize more of that precious dense power fibers and less bulk on the fleshy side you will be less mass by at least a little bit and move that neutral plain in the right direction to more towards the mid thickness of the Osage. 

[willie]

what glue will you use?

[Selfbowman]

Probably EA 40

[bjrogg]

I’m watching Arvin. 

Afraid I can’t give you any good advice. I haven’t even done a boo backed Osage.

Should be interesting to see results. Even if they aren’t what you hope for, they should be a valuable lesson in materials.

Gotta keep testing that edge.

Bjrogg

[bentstick54]

Like Bj, I’m following along but can’t offer any insights as my working experience has been only with Osage. Hoping it proves to be a success, but knowledge learned from the effort will be worth a lot regardless.

[Lehtis]

Guys have you ever seen bamboo with the nodes 30” apart? I’m supposed to talk to Jaap next week . He will probably tell me I am nuts. 🤠🤠but we all know that. I will see if he can prepare me 30” pieces with or without nodes and put a short 5” radius on one end for the fade ramps. I have some boo that would have one node in 30”. I don’t think I need to ramp the ends but about 3/4”. I’ll know more when I talk to Jaap.

I’ve made one 71” long ELB stylish bow with bamboo back that has only one node on the middle of it’s handle. I got that slice from my friend and he told the species is called loo bamboo. He has ordered it somewher far east (Asia). It’s radius was rather small so I had to grind it rather thin but so far it has worked fine on this ca. 75 lbs @ 28” bow. I’m on the road now but I’ll try to find some pics later to show.

[Lehtis]

Found some pics from another media… I’ve stained the back because of loo was a bit dirty looking and I didn’t want to grind it too much.
P.S. The belly is osage and core purple heart.

[Selfbowman]

Very nice bow.