Author Topic: First sinew job....little gaps?  (Read 9707 times)

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Offline Prarie Bowyer

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First sinew job....little gaps?
« on: December 28, 2014, 01:57:28 am »
First time laying sinew with Knox jellatin. 

Broke most of the tendons down fairly far bu the ends of each strand were tapered and or feathered.
Most were combed when dry to break them down further to get more glue between them

It is strange because I combed the first row and tried to keep the rest orderly but by the end I have some spots where there were small voids.  Do you guys fill these?

mikekeswick

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Re: First sinew job....little gaps?
« Reply #1 on: December 28, 2014, 03:24:34 am »
It has dried too quick. A fresh sinew back is just like a green stave. Get the majority of the moisture out slowly then increase speed of drying once it's hard all the way through.

Offline Prarie Bowyer

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Re: First sinew job....little gaps?
« Reply #2 on: December 28, 2014, 12:31:29 pm »
Ok...it is not nearly as thick this morning as it was when it was fresh.  I laid it yesterday afternoon in my basement (finished but cooler than the rest of the house).  Those little gaps were showing up as it first started drying.  It looks much more normal now.  And i'm wondering if I do in fact need a 2nd course.  I can't tell where my seams are but I kinda have 2 courses now.  The 2nd was done 2 strings at a time. 

Is it OK to just add right over the of what is already drying?  Or can I call this enough?

I hasn't started pulling the bow in to reflex yet but I didn't clamp in any either.

Offline JW_Halverson

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Re: First sinew job....little gaps?
« Reply #3 on: December 28, 2014, 02:29:23 pm »
You can poke bits of short sinew soaked in hide glue into the cracks, using the point of a knife or a needle.  Just don't do like I used to....fill 'em with glue!  All that does is add a lot of weight with no benefits.

And then when it is fully cured, you hear lots and lots of cracks and pops when you are first excercising it in for final tiller!  Bad for the old ticker, trust me!
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline PatM

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Re: First sinew job....little gaps?
« Reply #4 on: December 28, 2014, 02:42:47 pm »
Another first timer that missed my how to get smooth sinew build  along...
 A  properly applied sinew job with the right glue and ratio of glue to sinew shouldn't make a peep throughout the  draw.
  You can have this if you want. Smooth as can be.
 
 

Offline bradsmith2010

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Re: First sinew job....little gaps?
« Reply #5 on: December 28, 2014, 02:46:38 pm »
it wont hurt to add more, ,and you should bend the bow into reflex,, if you are using minimum amount of sinew it may not pull the bow into reflex,, and a sinew bow with no reflex can shoot well,, but will probably shoot slower than you would like,, :)

Offline Prarie Bowyer

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Re: First sinew job....little gaps?
« Reply #6 on: December 29, 2014, 11:51:24 am »
As it has been drying it has lost alot of thickness.  My sinew isn't even 1/8" thick.

is it too late to add more?  What about putting in some reflex?  Too late for that also? 

It is Yew from lumber so I don't want to overpower the belly.

Offline PatM

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Re: First sinew job....little gaps?
« Reply #7 on: December 29, 2014, 12:46:56 pm »
Many Asian sinewing techniques involve drying time between layers and increasing reflex with each layer. You can add sinew years later if you want since hide glue can be reactivated centuries later.

Offline Prarie Bowyer

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Re: First sinew job....little gaps?
« Reply #8 on: December 29, 2014, 11:45:45 pm »
Bigger problem!

Cracks forming along the side of the bow!  What the heck!  Is this fixable or fatal?

Online Pat B

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Re: First sinew job....little gaps?
« Reply #9 on: December 29, 2014, 11:59:06 pm »
On a sinew backed bow I built I added one course, let it dry for a few days to a week and added the second course concentrating on where it was needed. I've let them rest for a month between courses. I had no problems with the two courses adhering to one another. 
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline bubby

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Re: First sinew job....little gaps?
« Reply #10 on: December 30, 2014, 12:09:37 am »
Cracks in the wood or between the wood and sinew
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline Prarie Bowyer

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Re: First sinew job....little gaps?
« Reply #11 on: December 30, 2014, 01:55:04 am »
In the wood.  1/2 way down the thickness of the limb.

Online Pat B

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Re: First sinew job....little gaps?
« Reply #12 on: December 30, 2014, 08:46:01 am »
That sounds like win checks.  Pics!
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Prarie Bowyer

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Re: First sinew job....little gaps?
« Reply #13 on: December 30, 2014, 11:21:09 am »
I'll try to get them up tonight.  I picked up some thin locktight but I also have TB3.  Or more of the Knox.... and clamps.  And epoxy. And or wedges and glue. . . . .

Offline PatM

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Re: First sinew job....little gaps?
« Reply #14 on: December 30, 2014, 12:30:00 pm »
What wood is it?