Heat treating boo backed bow

[Eric Garza]

I'm sad that your bow chrysalled the way it did, though not surprised. While hickory is a durable wood I have found that it is easily overpowered by a bamboo backing, even when heat treated. This is especially true when you glue in tons of reflex, like you did. The hickory-backed-hickory bow I mentioned had 2 inches of glued-in reflex, and I found that to be too much, relative to the length of the bow.

[Eric Krewson]

I have made 3 or 4 bamboo backed hickory bows, all but one was made with existing bows, solid hickory bows that were made by other people, they were poorly tillered and had 3 or 4 " of string follow. One was made by me; my 3rd or 4th bow overall and fell into the "poorly made" category as well.

I used very thin bamboo and set my glue blocks at 3" of reflex hopping to have a 1" of reflex out of the blocks and shot in or at least a straight limb bow. I made all of my bamboo backed hickory bows 1 1/4" wide with a slightly rounded belly and 64" NOT. After shoot-in these bows all had just a little reflex.

The performance was very similar to a bamboo backed osage bow, I was impressed.

I also had at least 125 bows under my belt when I made these bamboo backed bows so my tillering was up to par.

[superdav95]

I’m gonna have to make one of these soon.  I’ve been reading some of the commentary on bbh and some of the common issues.  I want to test out some theory’s I have with this type of build.  One of which was already mentioned by Eric krewson about using very thin boo strip for backing.  Another theory I want to test is darker cook on the hickory belly wood.  I think the key is to pre tiller the hickory to a point of around 15-20” draw prior to glue up.  I also want to toast the inner belly wood of the boo lam slightly to drive out moisture.  One would have to be careful not to toast the strip too much to jeopardize the backing to keep heat from getting around to the back node side on the strip.  My theory in doing a darker cook on the hickory would be to move the neutral plane more in balance hopefully and to take the relatively harder boo strip backing better.  I suspect that the hickory can do it if tillered well and toasted well.  I would stick to a width of 1 5/8 at widest point and maintain this 2/3rds the way up the limbs then narrow towards the tips.  I would work limbs narrower if needed after glue up and tiller as needed.  I’m thinking 3” reflex glued in.  I suspect it would keep an inch or more of this in the end.  I’m also thinking that if this build did not go well or as planned I could belly lam with boo slats to possibly save it.  Actually this could be a solution for your build kidder!   Anyway not to hijack this thread here but fyi.  Just some of my thoughts on this build.  Cheers

[Kidder]

I’m gonna have to make one of these soon.  I’ve been reading some of the commentary on bbh and some of the common issues.  I want to test out some theory’s I have with this type of build.  One of which was already mentioned by Eric krewson about using very thin boo strip for backing.  Another theory I want to test is darker cook on the hickory belly wood.  I think the key is to pre tiller the hickory to a point of around 15-20” draw prior to glue up.  I also want to toast the inner belly wood of the boo lam slightly to drive out moisture.  One would have to be careful not to toast the strip too much to jeopardize the backing to keep heat from getting around to the back node side on the strip.  My theory in doing a darker cook on the hickory would be to move the neutral plane more in balance hopefully and to take the relatively harder boo strip backing better.  I suspect that the hickory can do it if tillered well and toasted well.  I would stick to a width of 1 5/8 at widest point and maintain this 2/3rds the way up the limbs then narrow towards the tips.  I would work limbs narrower if needed after glue up and tiller as needed.  I’m thinking 3” reflex glued in.  I suspect it would keep an inch or more of this in the end.  I’m also thinking that if this build did not go well or as planned I could belly lam with boo slats to possibly save it.  Actually this could be a solution for your build kidder!   Anyway not to hijack this thread here but fyi.  Just some of my thoughts on this build.  Cheers

Those are all good ideas. If you go that wide though (1 5/8”) you’re going to need to get an exceptionally low crown boo I suspect or you are going to run into thickness issues. I would guess that with the standard crowned boo I use, thinned to a knife edge that width would yield 0.14” thick or more. I think there is going to be a sweet spot that I didn’t hit where the width is right to allow thin enough boo.

[Eric Krewson]

I forgot to mention; None of my bamboo backed hickory bows were heat treated, I made them before heat treating came on the scene.

[superdav95]

I’m gonna have to make one of these soon.  I’ve been reading some of the commentary on bbh and some of the common issues.  I want to test out some theory’s I have with this type of build.  One of which was already mentioned by Eric krewson about using very thin boo strip for backing.  Another theory I want to test is darker cook on the hickory belly wood.  I think the key is to pre tiller the hickory to a point of around 15-20” draw prior to glue up.  I also want to toast the inner belly wood of the boo lam slightly to drive out moisture.  One would have to be careful not to toast the strip too much to jeopardize the backing to keep heat from getting around to the back node side on the strip.  My theory in doing a darker cook on the hickory would be to move the neutral plane more in balance hopefully and to take the relatively harder boo strip backing better.  I suspect that the hickory can do it if tillered well and toasted well.  I would stick to a width of 1 5/8 at widest point and maintain this 2/3rds the way up the limbs then narrow towards the tips.  I would work limbs narrower if needed after glue up and tiller as needed.  I’m thinking 3” reflex glued in.  I suspect it would keep an inch or more of this in the end.  I’m also thinking that if this build did not go well or as planned I could belly lam with boo slats to possibly save it.  Actually this could be a solution for your build kidder!   Anyway not to hijack this thread here but fyi.  Just some of my thoughts on this build.  Cheers

Those are all good ideas. If you go that wide though (1 5/8”) you’re going to need to get an exceptionally low crown boo I suspect or you are going to run into thickness issues. I would guess that with the standard crowned boo I use, thinned to a knife edge that width would yield 0.14” thick or more. I think there is going to be a sweet spot that I didn’t hit where the width is right to allow thin enough boo.

Yes I suspect a very thin boo lam will be needed. I agree there is a sweet spot too.  I may go a touch narrower depending on my weight and density of the particular hickory selected for this.  I have a 10’ section a moso pole that is quite large in diameter that may work well for this.  It’s between 5”-6” diameter from bottom to top.  I may start a build along post with this build.  I’m also thinking maybe doin a slight deflex in handle area and only reflexing the limbs a bit.  By posting this build I can show guys that may be interested the way I heat treat which is certainly just one way of doing it and not the only way it can be done.  Cheers.