Design considerations for boo backed ipe pyramid?

[Apex Predator]

I'd like to make a bow in the 60-62" range in the pyramid style.  I would love to use ipe with a boo backing.  My bamboo will probably only be around 1 3/4" wide and will have a pretty high crown to be that wide.  I want to try and keep the limb thickness the same the full length of the limb.  Is ipe a good contender for such a bow?  I love the dark rich natural color of the ipe.  Should I induce R/D in the glue up, or just some reflex?  How much?  I am shooting for 50@27.  Thanks.

[markinengland]

Ipe and Bamboo make a very powerfull combination. 1.5 inches wide should be plenty I would think. I imagine that a belly slat 3/8ths thick would give you a fair amount of wood removal practice!
In my experience Ipe works best kept failry thick in depth and thin in width. The wider the bow is the thinner you'll need to make the ipe, and ipe can crack along the grain when thin and if the grain isn't perfect.
The tips can be as thin as you dare, I would say a maximum of 3/8 wide. This means the bow needs to be laid out accurately but is achievable.
I think 1.5 inches wide at the widest point with a straight taper to the nock should get you in the right area.
I guess you will be glueing a handle on? I the belly slat is all the same thickness you'll need to add an thin section of material between the slat and backing going beyond the fades to stop the handle popping off.
A little reflex goes a long way with this combination. glueing in around 1.5 inches of reflex would be enough I would say. More and it may be too strong (back to making the Ipe too thin again) and you may have stability issues. You may not beleive this, but I made a very y Ipe ELB with 5 inches of reflex. It was pulling 120lb to get the string back 3 inches behind the handle! You will need a lot less wood than you think!
The bow should be quite fast.
Mark in England

[Rich Saffold]

Marty, 1 1/8" will get you those numbers in a pyramid style self bow. Which is about what I would use for a bamboo backed one as well. This insures you won't be removing too much belly wood to get it to bend.. I'd floor tiller the belly to the poundage of a 25-30# selfbow, and glue it up r/d if you wish with a net reflex of no more than an inch. 1/8" bamboo will double this poundage, and with the belly already floor tillered you won't be removing much wood while touching up the tiller.

This is important since making these too wide is the primary mistake I see. Bamboo can overpower any wood and the natural inclination is to remove the belly wood as opposed to removing wood from the sides..

Last week I finished up a 60" r/d longbow 55#@27". It's 3/4" wide through the grip...

Rich

[grantmac]

I thought I'd jump in here because I'm off on a similar tangent for my next bow.

I'm thinking partial pyramid with the first bit of the limbs parallel until the reflex? What thickness should I have the boo and Ipe for a 45-50@29 bow? I'm also thinking 66" NTN with a completely stiff handle.
I'm after as much speed as I can reliablty get.
    Sorry for the hijack,
                          Grant

[Apex Predator]

No problem grantmac, the more input the better!  I think Richard has this down to a science, but I don't know if I can get used to as narrow of a bow as he likes.  Maybe I'll try one of the sub 1" wide ones and see how I like it.

[Rich Saffold]

Grantmac, the combined thickness will be around 1/2" for bows like this.  I generally use a pyramid taper when laying out my limbs. It just doesn't look like one since they are quite slender..

Ipe does quite well as a pyramid style in selfbow form, and I highly recommend it. The practice of making a couple of these will help get used to this wood when doing glue up styles..

The density and varieties of this grain make for a lot more learning..I picked up ipe a couple weeks ago which was very different from any I had previously purchased.. So I still am seeing more of these 100 species as well.

Badger mentioned on another forum that a wide pyramid and r/d might not work so well, and I agree. I prefer to use it on the longbow and hybrid styles..Another thought I'm making one up in a Howard Hill style, and this past weekend at the local 3d meet shot with a fellow who had the sweetest shooting Hill bow I  had seen so I was inspired and think its' going to work well for these combos as well. Even though I had made similar bows in the past which did well.. It's an easy glue up.

Like skiing, or similar sports, progressive steps are a good idea with this stuff..

Rich

[adb]

With ipe/bamboo, I wouldn't go any wider than 1 1/8". Ipe is very good belly wood, and with bamboo backing, it makes a very strong bow. If you make it too wide, the ipe belly wood ends up being so thin, it's as thin as the backing. Ipe/bamboo excels with narrow widths, in an ELB style.

[Badger]

Actually ipe and bamboo will excel in most any style you choose to make it with as long as you stay aware of how heavy the wood is. Dan perry used an ipe/hickory to break some elb records with last year, I think he mad the bendy handle elb about 60" long. Really a versatile combo and will work for just about any style I can think of. Steve

[grantmac]

Rich,

Thanks for the input!
I just finished-up an 70" Elb of Hickory/Ipe with 2.5" of glued-in reflex and I was very impressed with the materials, only problem is that I didn't get it quite thick enough through the handle and so it's taken a small amount of set there. The tips are still about 1/2" ahead of the handle when unbraced for an hour. It is amazingly fast and smooth. The tips were kept around 5/16" and fairly stiff. I may make it into a takedown and retiller 5lbs lighter to keep the handle stiff, I'm not sure.

Back to this bow though. I've got a slat of Ipe 1.25x.25x72" and I'm thinking that it could just make a 45-50lb bow at 29". I'm thinking a very slender pyramid with just a little bit of deflex and about 1" of reflex ahead of the handle. The tips would be .25" ideally.

I think I will get to work on the belly slat, I should be able to get an eliptical tiller on it with width tillering alone correct?
         Thanks,
              Grant

[Rich Saffold]

I should elaborate on r/d on a pyramid..its a royal pain to try and get this wide a cross section to bend right out of the grip..I usually stretch this curve out bit on the styles I make which are similar to slender pyramid styles..

Grantmac, That thin of a belly  won't take much width tillering if at all to get that to bend how you want into the form..At 1/4" thickness you will need about 3/16ths backing coming out of the grip section to get close to 1/2" wide which you will need for the poundage and length you want..I have a 55# 69" longbow like this I am rather fond of.

Rich

[grantmac]

Rich,

So if I understand you correctly you keep the area just outside the fades fairly stiff then?
Should I perhaps keep the limbs parallel out of the fades? I'm thinking I might just glue it up without any tillering and then do the width tillering after the glue-up. To be honest this is the most complicated build I've yet done and I've got lots of questions. So far I've just glued on the handle to the Ipe with a little bit of deflex (1").

I'm not after much weight, but I do want the bow to be fast and consistant with light arrows.

Thanks,
        Grant

[Rich Saffold]

Grantmac, Make sure the outer limbs are working a bit more than right at the fades on a bow this long. Eliptical tiller is what you want..I started shooting in the same style bow today, and I took great care in getting the limbs past the curve to bend nicely..Since this bow will be shooting 350 grains in American rounds type competition..This 71" bow is also 3/4" wide and will be under 1/4" wide at the tips.

I didn't glue this bow up with any substantial net reflex under a half inch since this archer like to hold at full draw for about 2 seconds which throws keeping any reflex out.  It's holding at zero set now, but I will change that with the next hundred arrows or so...

If you have access to bamboo and ipe then you will end up making lots of these bows. Your dimensions are much more stable, and this should be an easy bow, but don't fret if something doesn't go right..learning this stuff is not without peril ( to the wood at least)

Rich-popped his share

[grantmac]

Well I'm glad I didn't glue-in much deflex in the handle, I won't add much reflex tomorrow when I do the glue-up. Thanks for the insight, I think I'll do a straight taper 4" from the fades to about 6" from the tips then go back to parallel to keep things stiff.
        Cheers,
               Grant