Walnut, advice and opinions?

[swotavator]

Hey all, this will be a third bow for my.  I got some nice boards of walnut, which i assume are kiln-dried.
I want to make a low-medium weight ELB, thinking 70-90 lbs.  I have read lots on how walnut is marginal, so i want to make sure i do this right.  I know it needs to be backed (poor in tension) and that walnut tends to fail under compression at weights higher than 50-60 (or so i have read).

Here is what i think i need:

first, I am relatively tall (6'2") so i was thinking of making this pretty long 78-79"?  The board is longer, so i can go up to 82, but that is probably ridiculous.
second, relatively wide and flat? 
third, backing?  I have hickory (3/8") readily available.  I assume i would have to thin and round it so that it was around 1/8 to 3/16.  Will it overpower the walnut at the weight/length i am thinking?  I have heard maple and ash are better.  would big box maple lumber work?  otherwise, i can go back to get a hard maple or ash board.

I also have a hickory stave.  would hickory backed hickory be a better combo?  could i fill with walnut to make a tri-lam?
should i just give up with the walnut and find ipe?  do flooring places sell longer than 72"?

if walnut, what kind of depth, widht?  i was thinking 1.4" wide with a depth (walnut only) of .75, tapering from there.

Thanks!1

[adb]

Ipe will make a better warbow than American walnut, especially if you want a narrow, stacked profile. I've tried making a tri-lam with walnut as the belly wood, and it chrysalled badly. However, walnut makes a great mid-lam.
If you have a hickory stave, and it's long enough, chase a ring and away you go.

[swotavator]

the hickory is a 1" thick board.  though it is very straight grained, i don't think it is straight enough to get a bow out of it, alone.  could i put the walnut between a hickory back and hickory belly?
or should i go out and buy ash, maple, or ipe?

[fishfinder401]

as a center lam between hickory back and belly it should work, but there are better combinations
noel

[adb]

Personally, I think hickory sucks as a belly wood, but makes the best backing there is.

[swotavator]

well since i have walnut, and it won't pair well with hickory, i think my best bet is to go get maple for it.
Then, for the hickory, i will have to find another core (ipe, lemonwood, osage, etc).  thats the project for the weekend.
i definitely wanted a very stacked and rounded crosssection, so i think with balance between the core and backing, i could get that with both of these (though i will shift the neutral plane towards the belly for the walnut one).

[swotavator]

Well,
I went to the yard, and there wasn't much good belly wood.  Wasn't sure about cherry and white oak to pair with a hickory backing, so i looked at the tropicals.  They had churasa, tigerwood, teak, mahogany and wenge.  I have heard the most about wenge, and i am not sure if the other stuff is good, so i  bought a wenge board.

Right now i am glueing it up (with about 1.5 to 2 inches reflex).  the boards are 7ft.  i drew it out so that it will probably be about 78-79 inches nock to nock and about 38 cm wide in the handle.  the hickory is about 3/8 inch, and i will heavily narrow, thin, and round that, and i intend on the wenge being about 7/8 inch thick through the handle.

I will save my other hickory strip for if i ever find osage, lemonwood, or ipe.  Might do a tri-lam with walnut in the middle.

Anyways, does anybody take issue with the dimensions I am going for?

[swotavator]

Well, the hickory backed  wenge is going well, but I also just acquired some ipe.

Here is a quick question:
If I intended on making a hickory backed ipe bow, what reasons would there be to make a tri-lam with something between the hickory and ipe?  Since ipe and hickory are amongst the best in compression/tension, wouldn't adding a middle lam just take away from the power/weight ratio?  Would it affect the speed of the bow? 

Besides looks, the only reason i could think to put something between ipe and hickory would be to allow a thicker bow for the same weight (in which case, i might consider this)
The woods i have available for a middle lam are:
Red Oak
Hard Maple
Walnut
Hickory
Wenge

[mikekeswick]

Remember that ALL the compression and ternsion work is being done by the first couple of mm of wood. The core is doing nothing other than taking a bit of sheer and being a spacer. So theoretically low sg woods are best for cores. Basically use whatever core you want or think would look nice. Why do you think a core will 'take away from the power/weight ratio'?

Ipe will make a 100lb bow at 1 inch wide...just...goto 1 1/8 th if you aren't sure.
 
If Black walnut can make a 50lb bow it can make a 150lb bow but it's width will be quite different. I think a lot of people get stuck on using certain dimensions then if a wood chrysals at that width you here things like - oh it will make a 50lber but....

[Ian.]

You make it sounds easy Mike, it really isn't an easy task to make a 130+ bow that performs well. What woods have you used to make very heavy laminates?

[mikekeswick]

Well it is pretty simple theory but execution is the key!
I don't think it's any harder to make a super fast 130lb bow than it is to make a super fast 50lber or a 15lber for that matter if all things are equal when testing the performance. You just have to pull harder on the tiller!
It's all about strain the bow doesn't know wether its 130lb or 13lb all the wood feels is the tension or compression. If your wood can handle the level's it can handle it. The real trick is dialing in the width without going too narrow when pushing for performance.
I personally really like ipe and greenheart for bellies as here in England you nead a wood that doesn't mind a bit of humidity...it's never been below 55% here all summer  . Ipe is strongest at around 12% mc.

[Ian.]

I would agree with how you make them, but having a 150lb bow on the tiller is not something many people can say they have done. Not loosing the weight in the final stages and tillering in a way which doesn't leave massive set is not just about getting the width right.  "pull harder on the tiller" I gave up on that and got a 6 in 1 block and tackle 

[mikekeswick]

I do a lot of climbing and slacklining so I know about pulleys! Google petzl pulleys if you want something that will never 'let go'! I also like a work out