Author Topic: I need some help before I mess up  (Read 591 times)

Offline krink

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I need some help before I mess up
« on: January 09, 2011, 05:04:00 PM »
This may get long winded so if ya have to use the head do so before you start reading.

My plan for my 3rd build is a sinew backed osage.  This is not going to be a stave I guess you would call it board lumber from 3 Rivers.  The handle and tip overlays are going to be mahogany.  I plan on introducing 1 1/2 inches of reflex.  Total length is undetermined at this point but I want it 66-68 inches.  My goal weight is 45ish @28 but under 50@29(my draw length).

My first question is do I put my overlays on after the sinew?

Next is my handle question.  My preferred grip is with my wrist slightly rolled forward.  I Shoot my wheeled bow this way, my pistol as well as my rifle with a forward grip.  It is natural for me.  Most board bows I have seen on here have a blocky grip.  Will I be able to get away with a more angular grip on a bow like this?  To show what i mean I took some scrap pine and roughly shaped and fitted it to my hand. I used the same dimensions that I should have when I get all of my parts.
 

Also the height of the board is aprox 5/8in.  How thin should I take the limbs down to before I start with files and what not?  Also do I apply my sinew before I rough cut the limbs or after.  I know I do not want to start any tillering with out the backing on it.  

Lastly I will be applying the sinew with hide glue and I have read somewhat conflicting drying times.  I have heard any where from 2 weeks to months on end.  How dry is dry enough? I did some samples here and it was all dry in 3 hours.  Is there something else going on with the sinew that I am not accounting for?

I did build a red oak bow and I followed 4est but I am unsure if the dimensions for RO are the same for osage as well as the process.  Thank you ahead of time for the input.

-kyle
The raising of that flag on Suribachi means a Marine Corps for the next five hundred years.
---James Forrestal

Sticks and stones will break some bones and feed my family this winter.

Offline John Scifres

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Re: I need some help before I mess up
« Reply #1 on: January 09, 2011, 05:20:00 PM »
As long as the handle does not bend, you can be very creative with the handle.  

All the rules for selecting an unbacked board apply for the sinew backed osage also.

I think 5/8" is not a bad starting point.

I get the bow to floor tiller before applying sinew.

I don't use hide glue anymore for sinew but used to let it dry a minimum of a month and 2 or 3 is better.
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Offline Silent Bear

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Re: I need some help before I mess up
« Reply #2 on: January 09, 2011, 06:05:00 PM »
Your not going to get any performance from the sinew backing it on a bow this long

If you have a good board I would leave it unbacked and save the sinew for a shorter bow
When a man speaks of truth he has nothing to hide. - Silent Bear

When a man moves away from nature his heart becomes hard. - Lakota

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Offline krink

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Re: I need some help before I mess up
« Reply #3 on: January 09, 2011, 11:52:00 PM »
Silent Bear-  I understand that using sinew on a longer takes away form the performance that it provides but do you think it wont have any effect at all?  I am only adding sinew because that is what I have.  I am on a budget (who isn't!) and I had to get other things I needed for my build and since I had sinew I didn't think I would need a wood backing.

John-  If I have a board with grain run out will I be able to floor tiller with out splinters coming up?


A question I left out is how can I seal the hide glue from moisture?  Poly?
The raising of that flag on Suribachi means a Marine Corps for the next five hundred years.
---James Forrestal

Sticks and stones will break some bones and feed my family this winter.

Offline KellyG

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Re: I need some help before I mess up
« Reply #4 on: January 10, 2011, 04:11:00 AM »
Krink,
I belive that brown paper works will for that, You can also go to the salvaiton army and see if they have any silk or linin cloths.
Kelly

Offline John Scifres

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Re: I need some help before I mess up
« Reply #5 on: January 10, 2011, 09:12:00 AM »
Sinew is heavier than wood.  Adding it to a longer bow adds mass out farther and therefore slows a longer bow more than it adds in tension strength.  Save it for a shorter bow.

If you have runouts, sinew probably will not help.  All the rules apply for choosing a board.  Here's some board bow instructions:    Ferret\\'s Board Bow Instructions
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Offline krink

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Re: I need some help before I mess up
« Reply #6 on: January 10, 2011, 03:26:00 PM »
After some reaserch I think I will go with silk as a backing.  I have seen that TBIII works well but I do not want a yellow tint.  Is there any other glue that will work as well with out the tint?

Also just to pose a question about sinew.  I understand that adding mass out at the tips hinders the bows preformance on longer bows.  Could you combine backing such as silk for the whole bow and use sinew for a short length to utalize its proformance adding ablities?  Maybe to add a bit of reflex to the first 12 inches off the fades with the sinew and then have the silk backing on the rest?  It would add more mass to the bow but if its in a area not working as much it should not hinder the preformance.  Or am I not grasping the abilities of sinew corectly?
The raising of that flag on Suribachi means a Marine Corps for the next five hundred years.
---James Forrestal

Sticks and stones will break some bones and feed my family this winter.

Offline vanillabear?

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Re: I need some help before I mess up
« Reply #7 on: January 10, 2011, 03:53:00 PM »

Offline John Scifres

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Re: I need some help before I mess up
« Reply #8 on: January 10, 2011, 04:39:00 PM »
Silk won't do a lot to hold down splinters if there are runouts on your board.  Runouts with osage are even more critical than on other woods.  If your osage board has runouts, use hickory or bamboo.

Sinew is magic in the right application but forcing it into the wrong design is asking for dissapointment.
Take a kid hunting!

TGMM Family of the Bow

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