Hickory backed Ipe Design Help

[deadsilence]

I have a few board bows under my belt now and I have now tried two different hybrids with no luck.  First hybrid popped three handles off before enough wood tore out to make it useless. The second one was a BBI trilam that had too thick of a bamboo back and my belly got to thin while trying to tiller enough to get the fades to stop bending. It developed a nasty hinge that i couldn't tiller around to save my life.

I'm looking for some help in the design department to give me the best chance at success. Right now i have a ipe lam that is 64" long x 1 5/16" wide.  I plan on a 10" centered, stiff handle, but this is up for debate. The ipe starts to taper in width and thickness 5" from the end of the riser. The width tapers to 1/2" tips and the thickness tapers from 3/8" to 1/4". I have pre tillered the belly by clamping the the ipe to a table at the end of the riser and hanging a 10lb weight 2" from the tip and tillered the strong limb till it matched the weaker one (3 3/4" of deflection). This was done just to get them bending even before glue up. Seemed like a good idea. I am planning on a 1/8" hickory backing.


The last two bows were glued up with deflex/reflex I am thinking of foregoing the deflex this time and gluing in some flipped tips like this?  Curve is 12" long and 3.5" tall.


I am thinking i am going to have to have a power lam to stiffen the fades and the handle area. 
I am thinking a 16" power lam with a 10" handle block since i have just a flat belly.
Power lam will be 5/16" thick at the max. Here are the thickness numbers for one side of the lam.
Thickness at -8: 0.0
Thickness at -7: 0.0390625
Thickness at -6: 0.078125
Thickness at -5: 0.1171875 (Handle will begin here)
Thickness at -4: 0.15625
Thickness at -3: 0.1953125
Thickness at -2: 0.234375
Thickness at -1: 0.2734375
Thickness at 0: 0.3125 (center of bow)

How does that look?

Thanks,
Jason

[PatM]

How about just a plain old straight glue-up?  Fill in that step between board bows and curvy ones first.

[deadsilence]

How about just a plain old straight glue-up?  Fill in that step between board bows and curvy ones first.

Sure that could be done, I am a little opposed to it as I am not a big fan of a longbow but that is personal preference.  I believe i would still have to have a power lam of some flavor to keep the fades from bending, correct?

I should have mentioned that i am looking for a hunting weight bow, 45# or greater, and my draw is a little over 28.

[PatM]

That may be a bit too sharp to do without kerfing the extremity.

[Morgan]

DS, this isn't my strong suit, but why would you need a power lam in a reflex tip only design? If your limbs taper well, I wouldn't think you would have to have one. In a bow with deflex at the handle, the force is different in the handle area. I may be wrong though.

[deadsilence]

DS, this isn't my strong suit, but why would you need a power lam in a reflex tip only design? If your limbs taper well, I wouldn't think you would have to have one. In a bow with deflex at the handle, the force is different in the handle area. I may be wrong though.

If this is true why did i do all that work???   Does inducing deflex into the handle make bows prone to bending near the fade?  If so would a flat handle with glued in flipped tips stand a better chance of not being weak at the fades?

[deadsilence]

Also would going with a more pyramid design help me?  Could I width taper from an inch or two from the fades to 3/8" tips and have a stronger fade handle area than on the deflexes i have tried?

[PatM]

DS, this isn't my strong suit, but why would you need a power lam in a reflex tip only design? If your limbs taper well, I wouldn't think you would have to have one. In a bow with deflex at the handle, the force is different in the handle area. I may be wrong though.

 His slat is pretty thin.

[Morgan]

DS, this isn't my strong suit, but why would you need a power lam in a reflex tip only design? If your limbs taper well, I wouldn't think you would have to have one. In a bow with deflex at the handle, the force is different in the handle area. I may be wrong though.

If this is true why did i do all that work???   Does inducing deflex into the handle make bows prone to bending near the fade?  If so would a flat handle with glued in flipped tips stand a better chance of not being weak at the fades?

In what I've seen, and that is limited, having a deflexed handle and reflexed tips does put force near the fades. I misread your first post of your slat being 3/8" at the thickest poin I read it as 3/4t. Ipe is supposed to be stout but that is aweful thin. Was your original deflex handles cut  curved or thin and glued into deflex?

[deadsilence]

DS, this isn't my strong suit, but why would you need a power lam in a reflex tip only design? If your limbs taper well, I wouldn't think you would have to have one. In a bow with deflex at the handle, the force is different in the handle area. I may be wrong though.

If this is true why did i do all that work???   Does inducing deflex into the handle make bows prone to bending near the fade?  If so would a flat handle with glued in flipped tips stand a better chance of not being weak at the fades?

In what I've seen, and that is limited, having a deflexed handle and reflexed tips does put force near the fades. I misread your first post of your slat being 3/8" at the thickest poin I read it as 3/4t. Ipe is supposed to be stout but that is aweful thin. Was your original deflex handles cut  curved or thin and glued into deflex?

it was cut curved at sanded to fit, glued with smooth on.

[Morgan]

My thinking is that if you glue the deflex and reflex into your slat and backing by themselves then trace the deflex curve onto your handle material, cut the riser and glue it in after the slat and backing is done, it should help you. Hope others chime in to prove that right or wrong though.

[bubby]

I imagine the main reason that your handles kept popping of was due to tillering and not design, you can get a niceslight recurve/ flipped tip with a glued on recurve, i will say one thing a power lam can be a bear on a glueup if everything doesn't go perfect

[Jim Davis]

I agree with the comments above about making straight bows until you have a high success rate.

I have no use for recurves (though I will shoot them happily if a long bow is not available). I have been making bows for 20 years, has to be well over 100 bows, and have had four break in the limbs.All but one of those were in the first year. Three were bad wood, one I just pulled too far.

I think those of you who run into more trouble are trying too many new things too soon.

Just my unsolicited opinion.

Jim

[deadsilence]

I agree with the comments above about making straight bows until you have a high success rate.

I have no use for recurves (though I will shoot them happily if a long bow is not available). I have been making bows for 20 years, has to be well over 100 bows, and have had four break in the limbs.All but one of those were in the first year. Three were bad wood, one I just pulled too far.

I think those of you who run into more trouble are trying too many new things too soon.

Just my unsolicited opinion.

Jim

I am willing to make a flat bow, i have made 4 already to get the tillering process under my belt.  Are you imply that this slat will make a flat bow and does not require a power lam? 

Let's start all overy.  If you had a piece of 3/8" ipe, what would you make with it and what would you starting dimensions be?

[PEARL DRUMS]

Make whatever bow makes you happy, its your hobby and your spare time. We aren't all created equal and what seems too much for one person is nothing for the next person to pull off. I've seen some incredible 5th, 8th and 13th bows from folks in the past. Time in the saddle means squat. Drive, determination and understanding does.

A 3/8" thick slat of ipe will require a 3rd complete lam or at least a power lam to make a rigid handle bow.