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Author Topic: Well I almost made it.  (Read 2571 times)

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Offline mwosborn

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  • Mitch Osborn
Well I almost made it.
« on: January 31, 2014, 10:41:49 pm »
About a year and half ago or so I made an erc sinew backed that turned out pretty nice but had just a sliver of heartwood on the belly.  I wanted to make one with more heartwood.  Had a good straight stave with only 1 major knot so I gave it a try.  Cut off most the sapwood with the bandsaw and then worked the rest down to the heartwood.  Backed it with some rawhide and started on my way.  The stave ended up being just big enough to make it about 1.75 wide to mid limb and 68" long.  With all heartwood I wasn't expecting a lot of weight so I was wanting 40-45 at 27"

Well I made it to 25" and mid 40's on the tree.  Tiller was looking good.  Decided to pull it in my hand a bit. Felt good.  Pulled a bit further .....BOOM....both limbs snapped about equal distance from the fades.  It would have been pretty  :'(

Maybe try another and leave some sapwood.  Have a hackberry and some others to finish first though.

Just thought I would share.

Mitch

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Enjoy the hunt!  Mitch

Offline JW_Halverson

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Re: Well I almost made it.
« Reply #1 on: January 31, 2014, 10:45:59 pm »
AAAARGH!

That's erc for you.  It is or it isn't.  No in betweens!
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Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline nclonghunter

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Re: Well I almost made it.
« Reply #2 on: January 31, 2014, 11:00:01 pm »
It looks like it was a bend in the handle bow. I am surprised the rawhide broke also. I think what I have learned on here then the bow failed in the belly because the back was stronger. Does that sound right? I am interested because I have a desire to make a ERC bow. Was considering cutting one down tomorrow. So, would the rawhide back make it too strong for the belly. What is the best design when building an ERC ?

Sorry this bow just triggered a bunch of thoughts and questions...
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There are no bad knappers, only bad flakes

Offline JW_Halverson

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Re: Well I almost made it.
« Reply #3 on: January 31, 2014, 11:03:12 pm »
If the belly fails, it just hinges until it crumples.  Did that with redwood and rawhide once.
If the back fails, then the limb breaks off like what is shown in the photos. 
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Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline PatM

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Re: Well I almost made it.
« Reply #4 on: January 31, 2014, 11:07:43 pm »
Rawhide can be incredible for holding a back together but it can also be a bit fickle depending on type of hide, which part of the hide the strips came from and how it was actually processed into rawhide.
 The'"partial decay" method of getting the hair to slip is probably a bit of a fine line when it comes to ultimate strength.
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Offline mwosborn

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  • Mitch Osborn
Re: Well I almost made it.
« Reply #5 on: January 31, 2014, 11:16:33 pm »
From my experience, rawhide can help a tension weak wood or protect from splinter on a violated ring etc.  But it doesn't do miracles.  ERC is tension weak and especially the heartwood.  I knew going in that it may well break - that is why I backed it with rawhide and rounded the belly quite a bit.  I just pulled it too far for the bend I had tillered.  The handle was not bending and the last 4-5" of the tips where not either - maybe they should have been.  It was 68" long and I wanted at least 40# at 27" - came up short.  On to the next one.

If you are wanted to make a erc and want a high chance of success I would make it a bit shorter and sinew back it.  They make a nice light quick bow (IMO).
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Enjoy the hunt!  Mitch

Offline DuBois

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Re: Well I almost made it.
« Reply #6 on: January 31, 2014, 11:24:27 pm »
Bummer man. I had one erc do that on one limb only. It was my 5th bow and I had thought before that that rawhide would stop a break n half like that but I saw then that it wouldn't. Sure surprised me when it snapped and flew across the room  :o
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Offline Pat B

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Re: Well I almost made it.
« Reply #7 on: January 31, 2014, 11:48:58 pm »
I had a rawhide backed ERC ELB fold over on the top and bottom limbs about where these broke. It was about 1/2 heart/sapwood. On mine the belly collapsed. Its a shame your bow blew but that's how it goes sometimes.   I use a good bit of rawhide for backings. I now for a fact it will not keep a doomed bow from blowing.  :o
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline lostarrow

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Re: Well I almost made it.
« Reply #8 on: February 01, 2014, 01:24:26 am »
Quote from: PatM on January 31, 2014, 11:07:43 pm
Rawhide can be incredible for holding a back together but it can also be a bit fickle depending on type of hide, which part of the hide the strips came from and how it was actually processed into rawhide.
 The'"partial decay" method of getting the hair to slip is probably a bit of a fine line when it comes to ultimate strength.

 If it's starting to decay , it's not being done right Pat. The idea is to super saturate with water. this loosens the folicles and lets the hair "slip" . The water is changed as often as needed to prevent bacteria from building up. If it even starts to stink, you're screwed. Cool weather is preferable. I would agree that there would be less speculation on a dry scrape hide , but half the battle is fought before you even start to prepare the hide, if it's coming from a friend and not stored promptly and properly ;) ::).
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