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Author Topic: Please have mercy and give input on my glass bow project.  (Read 2083 times)

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Offline IrishJay

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Please have mercy and give input on my glass bow project.
« on: April 01, 2019, 07:58:11 pm »
I know this is a dangerous subject to bring up around this crowd, and I'm definitely not giving up on building traditional bows, but I decided to try my hand at a glass one.

It's a 71" ntn ELB, glass back is already on and it's tillered out to 47# @ 31". My original plan was to lay glass on the belly post tiller, but now that I'm looking at it I think toasting the belly might be a better move.

My biggest concern is the glass back overpowering the belly. I've seen no signs of chrysals yet, but I haven't shot it yet either, just drawn it to full length. And of all the ways I've had a bow fail so far, back overpowering the belly hasn't happened to me yet so I'm not even sure if that's something I'd see on the tree or if it only manifests after shooting.

Thoughts?



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Offline IrishJay

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Re: Please have mercy and give input on my glass bow project.
« Reply #1 on: April 01, 2019, 08:09:27 pm »
Forgot to mention it's one piece, no lams, red oak board.
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"The best camouflage pattern is called, 'Sit down and be quiet!' Your grandpa hunted deer in a red plaid coat, think about that for a second." - Fred Bear

Offline Hawkdancer

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Re: Please have mercy and give input on my glass bow project.
« Reply #2 on: April 01, 2019, 08:54:00 pm »
You might try to contact Jack Moody, a bow maker in Loveland CO, who glass backs his elb's.  That may Help keep you in better standing here, as fg is gross profanity, and sacrilege!  I'll try to find his email and pm you.
Hawkdancer
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Offline IrishJay

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Re: Please have mercy and give input on my glass bow project.
« Reply #3 on: April 01, 2019, 08:54:47 pm »
Thank you, much appreciated.
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"The best camouflage pattern is called, 'Sit down and be quiet!' Your grandpa hunted deer in a red plaid coat, think about that for a second." - Fred Bear

Offline Pat B

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Re: Please have mercy and give input on my glass bow project.
« Reply #4 on: April 01, 2019, 09:23:49 pm »
Some years ago a few glass bow companies decided to try glass backed wood bows. Didn't take them long to abandon the idea.
If you do want a better chance at success try a wood that is stronger in compression like osage or ipe. Red oak just doesn't have what it takes...usually.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline IrishJay

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Re: Please have mercy and give input on my glass bow project.
« Reply #5 on: April 01, 2019, 09:56:30 pm »
To ask a more general bow building question, what are the mechanics of a back overpowering a belly? I understand that its caused by the tension strength of the back being greater than the compression strength of the belly. And I understand that it causes crushed fibers in the belly. I'm just a little fuzzy on the how and why of it.

Also is it something that would happen just drawing the bow, or is it somehow related to the recoil of actually shooting the bow?
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"The best camouflage pattern is called, 'Sit down and be quiet!' Your grandpa hunted deer in a red plaid coat, think about that for a second." - Fred Bear

Offline Pat B

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Re: Please have mercy and give input on my glass bow project.
« Reply #6 on: April 02, 2019, 05:11:46 am »
Woods are stronger in tension than they are in compression. The reasons those bow companies discontinued the glass backed wood bows is the bellies couldn't take the tension of the glass backing.
 Did you use a strip of bow glass on the back of your bow? What binder did you use for the glass?
Over the year, here on PA we've had this discussion quite a few times. We are here to build wood bows and to learn how to successfully build an all wood bow without an artificial crutch. It can and has been done and I might add with some incredible results. Just look at BOM over the years.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC
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