Laminate Reflex Long bow Question

[peacefullymadewarbows]

So I had a Bilaminate glue up ready to go all the way until a question came to mind. How much reflex do I need to induce on the glue up for the blank to maintain 1.5-2" of reflex after unclamped? For background the pieces are an 82" long piece of black cherry that's about 1.675" wide and and 1.5" thick at the handle. I cut bandsaw straight line tapers leaving the center 6 inches full thickness and the tips at 5/8" thick. This was with the hope that I can just clamp the reflex in the center and the bend would be roughly round arc so tillering is not a drag. Backing strip is 82" long 1.5" wide piece of moso bamboo that averages about 3/16" thick at the crown of it (this is not including the nodes they are thicker). After having planed the bamboo I feel like no matter how much reflex I glue in the belly piece is so much thicker than the boo that it will over power and pull it back neutral. Any thoughts are appreciated. End goal is a round arc long bow of 100-110 # @ 31" that maintains 0.5-1" reflex after shooting.

[PatM]

Those two materials are not a good choice.

[DC]

I have no knowledge about Black Cherry so I can't comment on the suitability of the woods. I have found that the amount of springback is very dependant on the thickness of the belly. I always sand the boo so it comes to or very close to a knife edge so it's thickness depends on the width of the bow and the radius of the boo. If you have a bendy belly wood it will hold the glued in reflex better than if you have a stiff belly. It's just the strengths of the two balancing each other. All that said it's in the ball park of about a third, much like steaming. Put in 3" get 2" out. But on top of that there is tendency for the bow to gain reflex as you tiller and remove belly wood. This depends again on the thickness/stiffness off the belly. So if you have a good reflex gain it can replace some of the gluing loss so you might put in 3" and get 3 or 4" after tillering. But you'll probably gain some here and lose some there. It's crap shoot. Not a lot of help am I

[bownarra]

Get some ipe
B. cherry and boo are not a good combo.
If you want to hold loads of reflex then make thinner laminates. Nothing over 1/2 certainly.
If you haven't made many bows forget the reflex.
Glue it up with 1 inch max.
Also longbows should not be arc of a circle....they should be tillered to be elliptical.

[peacefullymadewarbows]

I've made a number of self bows but only a few laminates. I have a hickory backed cherry that's faired very well so far. I figured Boo would be similar in its properties. This piece of boo is fencing boo which is of questionable quality. Feels lighter in density but that's only by feel. I have better moso set aside for the ipe boards I have. This will hopefully function as a scrap wood practice run. If it works that's great but no love lost if it breaks or takes terrible set. Will still be a teaching moment. I'll follow the two thirds rule and go for an elliptical tiller. Thanks guys.