Author Topic: Laminate question  (Read 3115 times)

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Grunt

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Laminate question
« on: September 23, 2009, 06:40:30 pm »
I've got some Ipe, Hard Maple and some Bamboo and I am going to start to learn reflex deflex laminate bows. My question is about laminate thickness. I figure to glue up a 1 1/4" wide blank tomorrow. I have a 20"bandsaw that will allow me to resaw and a 6x48 belt sander to clean things up. I've resawed the Ipe to 1/2 " x 1 1/4  for the belly and I want to put a 18" piece of hard maple inside for the power lam. Should I taper the Ipe from the center 1/2" out to 3/16 at the tips or should I go thinner? Looking for a 50 lb bow. I figure the maple will taper from 1/2" at the center to feather on each side or should I resaw thinner than 1/2? The bow is starting at 68" but might end up shorter. Urac and a hotbox to cure stuff up. My form has a center post 3" high, midlimb 2 1/4" high and 6 1/2'high recurve ends. I'll glue the handle lams on after cooking the bow. As you all can see I've got enough stuff to drive myself crazy right now but I'm a glutton for punishment so what do ya think?

Offline avcase

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Re: Laminate question
« Reply #1 on: September 23, 2009, 09:07:38 pm »
It depends on the specific properties of the bamboo and ipe that you are using and also depends on how steep you cut the taper in the maple lam. 

Here's a guess. I would grind the ipe down to about a constant .32" thick wIth the bamboo half as thick or a bit less.  Then I'd mark a 3/16" wide tip and draw a straight line from just inside the fades to the tip. Glue up the bamboo, maple, and ipe in a mild r/d profile with some tightbond III. Give it plenty of time to dry. Bandsaw just outside the lines, smooth the edges, slightly round over any corners, and add a small tip overlay with a back cut nock.   String it up and shoot it.  Try to avoid tapering the thickness and leave it parallel.  You may want to narrow the outer limb a bit more later. It will be smooth and perform as well as the best modern composite bows and you will love to shoot it!
Alan

   

Offline Tom Leemans

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Re: Laminate question
« Reply #2 on: September 24, 2009, 09:42:29 am »
If you were to visit the bow building section of the TG site, there's a 16 year old kid named Nick in the Netherlands that has building ipe/boo/?? bows like crazy. Look for anything from "dutchwarbow". You'll get plenty of ideas there. Heck, he has next to nothing for tools, but he's got natural talent.

Offline snedeker

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Re: Laminate question
« Reply #3 on: September 24, 2009, 10:32:51 am »
If I were to do it, I'd use about a 3/16 maple power lam, smoothly tapering in thickness each way from the grip.  I'd leave the ipe 1/2" thick at first for about 10" in the mid portion of the bow, tapering to about 1/4 at the tip.  This allows enough thickness of ipe in the handle area so you aren't plagued by the handle popping off.  It is a little thick though if the goal is a lot of radical shaping in the form.

Dave

Grunt

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Re: Laminate question
« Reply #4 on: September 24, 2009, 12:54:34 pm »
It's in the hot box now. I used a Ipe belly 3/16 at the ends tapering to 1/2 at the center. Maple rizer about 3/16 at the center tapering to feather 18" long. Boo back 1 1/4 wide 1/8 thick. I will build up a handle out of 3 pieces. 2 of maple one something dark.  I will see how this goes.  Many thanks for your help. I'm going to have to build more of these beasts, it's fun1

Offline Justin Snyder

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Re: Laminate question
« Reply #5 on: September 24, 2009, 05:10:26 pm »
You are going to take a lot of wood off when you start tillering.  ;D Don't get impatient.  I just finished a boo/ipe bow of similar dimensions. It is 66" long 1 1/4" wide from fades to midlimb, then tapers to the tips. The ipe is 3/8 at the fades and 3/16 at midlimb, then back to 1/4" at the non bending tip. The boo is 1/8" thick.  It still pulls 55# at 26".
Everything happens for a reason, sometimes the reason is you made a bad decision.


SW Utah

Offline Jesse

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Re: Laminate question
« Reply #6 on: September 24, 2009, 09:49:27 pm »
It depends on the specific properties of the bamboo and ipe that you are using and also depends on how steep you cut the taper in the maple lam. 

Here's a guess. I would grind the ipe down to about a constant .32" thick wIth the bamboo half as thick or a bit less.  Then I'd mark a 3/16" wide tip and draw a straight line from just inside the fades to the tip. Glue up the bamboo, maple, and ipe in a mild r/d profile with some tightbond III. Give it plenty of time to dry. Bandsaw just outside the lines, smooth the edges, slightly round over any corners, and add a small tip overlay with a back cut nock.   String it up and shoot it.  Try to avoid tapering the thickness and leave it parallel.  You may want to narrow the outer limb a bit more later. It will be smooth and perform as well as the best modern composite bows and you will love to shoot it!
Alan

   
So you say to start with 3/16" wide tips and narrow more later? Hmmmm ???
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
    --Frank A. Clark

Grunt

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Re: Laminate question
« Reply #7 on: September 25, 2009, 12:36:33 pm »
I was thinking he meant thick instead of wide, I hope. I definitely now have everything I need to drive myself crazy. I dug out my calipers and conversion tables and am now thinking in .000 instead of 1/16's.  Ain't got a head ache, yet. Glued the handle up with three pieces .300 x 1 1/4  12" mahogany and walnut and it's back in the hot box. I guess all this exact measuring is so when the bow comes out of the form it's floor tillered and ready for a long string. Can't wait to get my hands on it and start shaping the handle and getting it bent on the tree..

Offline Justin Snyder

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Re: Laminate question
« Reply #8 on: September 25, 2009, 07:40:23 pm »
Floor tillered if you are looking for a 100# bow maybe.  ;D
Everything happens for a reason, sometimes the reason is you made a bad decision.


SW Utah