'boo backed / 'boo bellied....need advice!

[rocdoc]

Thought I'd get cute and make a 'boo backed / 'boo bellied bulletwood bow.  I backed the bullet plank and then 'flat belly tillered' it to 44# @ 28".  The tiller looks very good at this point.  I'm shooting for 50# @ 28".  My belly boo is very thin and after gluing it on the tiller is still very close!

Problem is, the bow weighs 50# @ 24" and I'm concerned about altering the tiller when I scrape between the nodes to drop weight.  How much weight can I expect to be able to take off by scraping the boo?  Like I said, the boo is very thin on the belly.

Any advice would be appreciated JOHN, JD ???

[the Ferret]

Wow you gained approx 18# with the addition of that boo. Unreal. Can't help with with this one Doug, I am now the student ready to learn from you, JBS, JD etc. Will watch this with great interest.

[Sparky]

Are you saying you have BB full node on the belly as well? Dang...I don't know if scraping in between the nodes will get you what ya want for end results. Sounds like at best a series of hinges...at worst, you'll violate the power fibers in the Boo resulting in I don't know what?
 IMHO...I would Take the nodes down to a pleasing height and try to reduce weight with width reduction and leave the belly wood alone unless you have a tremendous amount of weight to loose.
  I have never done one bit if it were I..that is what I would do....  
  Very intersting concept....

Sparky

[rocdoc]

Sparky....I've put boo underlays on a few bows and really haven't had any hinge problems.  The nodes remain 'proud' but I do work them down as well.

Mickey.....that's what I thought!  I expected maybe 8 to 10 pounds.  I think that Urac has some very good bow qualities to it       My boo was DEFINITELY thin, felt like a piece of poster board before I glued it on.

[horseapple]

Doug, how wide is the bow? And how much have you already traped the back?  I've only experimented with just a handfull of boo and boo:) Sturtevant has been building quite a few of these bows so maybe he'll chime in, he always has great advise... Really not much you can do but scrape the belly from node to node and try not to flatten the nodes, scrape a little here and there and work the snot out of it on your tillering form, one other thing is once you've scraped the belly boo you've thinned the power fibers, so what I do is lightly torch the belly boo until its a nice light tan color, heck it'll probabaly add 5 pounds back to the bow:) your actually tempering it or drying the snot out of it:) but if you don't torch the belly you'll have a bow that will be somewhat of a dog at speed, just try it you'll be shocked:) also tiller usually doesn't change with this process

[Timo]

Could a fella trap the belly and back?

(Forgive me,I'm new at this)  

[Brian Halbleib]

Not sure if you have any old "Primitve Archer" magazines around but in the Fall 2001 issue, Stefan Seitz wrote a good article on an all boo laminated bow. I just dug this out a few months back because I'm ready to try one myself.

He says in one part of the article "Due to the high tension strength of bamboo, the pressure on the belly is the critical thing. So, contrary to the usual way of tillering a bow, tillering on an all wood laminated bamboo bow is done only on the back!"

At the time of the article, he had built 5 of that type of bow and the pictures were pretty impressive.

Keep us posted.

-Brian

[rocdoc]

JD....The bow is a 'D' bow with just a little bit of bend in the handle, 1" wide handle to mid-limb and tapering to 3/8" at the nocks.  63" ntn.  

Thanks for the tempering advice.....I'll try that.  Not sure I like the way you said TORCH IT!    

[rocdoc]

Almost forgot to answer your trapping question JD.  I didn't trap it very 'deep' on the back, just about 60 degree angle and only down to the edge of the bulletwood....didn't really trap the 'boo into the wood.

[horseapple]

Brian, I remember the article, sounded weird to me to about taking boo off the back, heck I'm not about to take a chance and scrape thru the power fibers on the back, five bows without a failure sounds solid tho... Hey Doug why not try it and tell us how it works:) no realy as much time and attention that I take to not ding or mark the bamboo's back I'll hafta pass on tillering it from the back:)
Tim, you probably could trap back and belly but it might get kindof squirrely on side to side bending..

[Timo]

Then hunt squirrels with it!.....jesh! LOL  :D

[horseapple]

lots of them squirells around Stillwater OK:)

[Sparky]

Oooooooooo......


Sparky

[NEW GUY]

This is cool Rocdoc.  Could we maybe get some pics, so us newbies could get a feel for some of the things yall are talkin about.

[rocdoc]

Shane.  I didn't take pics up to this point but I'll try and get some tomorrow.  Maybe by then John Sturtevant will have given me some advice.    

JD....squirrels huh!  I guess I had that commin'...did you get the basket of oranges I sent ya?     :rolleyes:   When I get to the point of tempering the belly boo, can I use my heat gun?  I know you prefer your torch, but you're a border line  "pyro" and I prefer the use the gun when I can.

[Pat B]

You can get some weight off by scraping the sides. Also, like Timo said, trap the back. I had to do that on a boo backed lam bow I built. I beveled the top edges to where the back was about 1" wide and the limb was 1 1/4" wide. Do it gradually and check weight often.   Pat

[wingnut]

Doug,

It's sounds like you might be close enough to strt rounding your edges.  This will take a bit of weight off.  Also work that bamboo a lot.  I have had it relax after 50 pulls or so and settle in a few pounds lower then I thought.

Mike

[Dano]

Interesting Doug. I was given a fiberglass longbow a friend made, this bow was about 100#@28. I took the bow limbs down to 1" then trapped the belly till it was 5/8" at the fades down to 3/8" at the tips, ended up about 60#@28. I know this is a little different but trapping the belly width does take a ton of wieght off. Just my 2 cents. Good luck nice project.

[horseapple]

Doug, sound advise from all good luck and try and post some pic's

[John Scifres]

I've never made one like that but, I'd trap it to the extent possible the sand it all down and shoot it at target weight (whatever draw that is) until it settles in.  Then I think I'd start narrowing limbs until I had my weight and tiller.  Shouldn't take too much.  I saw that article a couple years ago too and had trouble visualizing it.