Yew billets belly drop build with sinew backing.

[superdav95]

Made some progress today on these bows.  Got them both to same basic floor tiller.  Tips flipped on both.  I heated in some reflex to both as well.  I’ve got to fix a little more twist of the one end on the sapwood bow.  Gonna fix that twist before I start any sinew.  I plan to put some fine grooving on the back of the bows prior to sizing with thin bud glue.  I’m gonna try a chewed sinew application on both.  Never done it so will see how things go.  Here’s some update pics. 

[superdav95]

Couple more

[Aaron1726]

Those look awesome.  I'm interested to hear how the chewed sinew works out.

[wooddamon1]

Looking good so far, Dave.

[superdav95]

Thanks guys.  I’m very interested as well.   

[Pappy]

Looking good Dave, Lots of chewing on them bows but feel sure it will work if your yaws don't get worn out. 
 Pappy

[Doug509]

What a great project and comparison. I just graduated from vine maple and started my first yew project.  I might have to violate some sapwood on the stave I chose.  Do you absolutely have to add sinew or just for insurance?
Good luck. I will be following

[superdav95]

Looking good Dave, Lots of chewing on them bows but feel sure it will work if your yaws don't get worn out. 
 Pappy

Thanks pappy!   Ya it’s gonna be lots of chewing for certain.  I may have to split it up over a couple days.  I’ve been toying with the idea of a spit bowl and letting it soak it there too to assist with the amount of sinew I’m gonna be dealing with. 

[superdav95]

What a great project and comparison. I just graduated from vine maple and started my first yew project.  I might have to violate some sapwood on the stave I chose.  Do you absolutely have to add sinew or just for insurance?
Good luck. I will be following

Thanks Doug.  You don’t always need to back yew if rings are violated.  In fact depending on the amount of violations and where along the limb you may not need to back at all.  Many guys have build nice yew bows with violated rings with no backing.  It’s mainly an insurance measure.  I’ve made them with or without backing.   I back all my yew bows with rawhide now.  I find it provides that protective layer for the relatively soft sapwood.  It also provides a nice canvas for stain or paint as well.

[superdav95]

I spent some time today on both of these after resting these from the heat corrections and flipped tips were put in.  Floor tillered bow to roughly 55-57lbs at low brace.  Both bending evenly and balanced.  Little heavier then I was originally thinking before starting sinew but I think this will assist with not stressing the belly wood too much and have the sinew work well with unstressed belly fibers.  I also don’t want to induce too much reflex with these Botha at the end.  My goal for these is around 3-4” retained reflex.  Right now they are about there close to 4” reflex.  With the sinew added I will gain around 2” more.  I figure I’ll loose about 2-3” after shoot in.  That will give me a very easy shooter out of both.  On my other sinew backed bows I would lay down 2 or 3 layers of thinner bundles carefully measured and pre soaked and combed out and washed I would used measured amounts of hide glue on these bows I’m going for a different approach.  I’m planning to apply 60-70grams of sinew on each bow.    Some may seem to think this is a little on the light side for sinew.  it may be but I guess it depends on the build.  I’m going to only sinew about about 15-20” of each limb and tie off with a wrap about 6” from the end basically where the flipped tips are starting.  I’ll use some small shorter strands to incorporate at the handle overlapping a bit into the limbs.  I’m gonna go for one big layer.  This goes against my typical trusted method.   I will measure and separate equal bundles for each limb of about 30-35grams.  Let the chewing experiment begin!!!   Here’s some pics of the bows to where I’m at now.  Notice the mild dishes out belly of the sapwood bow.  I decided on this slight hollow belly due to the higher crown.  Hoping it will even out the stresses better.   I just followed the contours feeling along with my fingers to get it close. 

[superdav95]

Ok.  So change of plans!   I’m not going to chew the sinew for these bows.  I tried to chew a small batch and I can’t stomach it.  I know I know the purests out there may say oh man up and just do it!  Well I could maybe do it over several applications over several weeks little at a time maybe to spread it out.  And maybe I could manage to do one bow fine without tossing my cookies but my gut feeling is that I would be nauseous the entire time.  Here’s the thing.  I have most of my sinew that I’ve broken down as moose and elk back strap.  I cannot stand the taste of it.  I’ve tried chewing a few back straps from deer and can manage it fine without feeling nauseous the whole time.  I don’t have as much deer sinew otherwise I’d just use it instead and proceed with original plan.   As an alternative plan for these bows instead I’m gonna go a different route entirely.  I’ve always wanted to test out tb3 with sinew.  I’ve never done it and heard of the odd account of reputable bowyers who have done it.  This method has its benefits and drawbacks compared to “the matrix” of hide glue and sinew.  The benefits I foresee could possibly be:

1. Increased water resistance
2. Increased adhesive properties. 
3. Easier to repair if repairs needed in the field. 
4. Water soluble and easy clean up and application. 

Downsides could be:

1. Less compatible with sinew then hide glue
2. Little or no matrix benefits ?
3. Added mass with tb3 glue?
4. Longer to dry?   

Lots of unanswered questions for sure.  Let’s find out together. 

Here’s what I’m gonna do based on what research I’ve done and what little on this there is out there. 

I’m gonna still use 60-70 grams of clean brushed/combed sinew strands per bow that have been thoroughly washed and cleaned.  Dry weights prior to cleaning and removal of any little unwanted bits will be close. 
I’m going to size the back with a thinned down tb3 glue and water first and slightly heat up the back of the bow which will be thoroughly cleaned from any oils and such.  The surface will also be roughed up too. 
I’m gonna soak the sinew in a watery very thin tb3 glue solution prior to using full strength glue when laying down on the bow. 

I’m going to wrap the sinewed bows with cloth strips or bandages while drying. 

I’m going to back string the bows inducing an inch or so additional reflex beyond the 3” now in the bows while the bow dries for a few weeks. 

Anyway. Let’s learn together.  I’ve never done this so any advise would be welcome guys


Dave

[mmattockx]

The benefits I foresee could possibly be:

1. Increased water resistance
2. Increased adhesive properties. 
3. Easier to repair if repairs needed in the field. 
4. Water soluble and easy clean up and application. 

I'm curious to see how it works out. I've backed a couple bows with fabric and TB3 and I've patched a couple knots using synthetic rope fibres and Knox gelatin. I would say the gelatin/hide glue wins hands down in terms of strength and clean up is just as easy as the TB3. The TB3 never really dried truly hard on the backings I used and I would guess it will allow some creep over time due to the rubbery nature of it. The hide glue is rock solid in comparison and is still holding the synthetic fibres with no trouble after a couple thousand shots despite the fibres being much stiffer than the wood they are glued to.


Mark

[superdav95]

The benefits I foresee could possibly be:

1. Increased water resistance
2. Increased adhesive properties. 
3. Easier to repair if repairs needed in the field. 
4. Water soluble and easy clean up and application. 

I'm curious to see how it works out. I've backed a couple bows with fabric and TB3 and I've patched a couple knots using synthetic rope fibres and Knox gelatin. I would say the gelatin/hide glue wins hands down in terms of strength and clean up is just as easy as the TB3. The TB3 never really dried truly hard on the backings I used and I would guess it will allow some creep over time due to the rubbery nature of it. The hide glue is rock solid in comparison and is still holding the synthetic fibres with no trouble after a couple thousand shots despite the fibres being much stiffer than the wood they are glued to.


Mark

Very interesting mark. Thanks for the insights.   I’ve only ever used tb3 in backings like snake skins or rawhide.  I’ve dabbled with other coverings like fish skins and other various organic material but for those I used hide glue or sturgeon fish glue.  I didn’t find my hide backings or snake skins applied with tb3 to be more flexible or rubbery.  Mine dried up quite good actually.  I’ve been working on processing sinew today in preparation for whatever I end up doing on these bows.  I have half a mind to just go with what I know will work good which is hide glue and clean sinew in measured bundles. But that doesn’t allow me to explore the unknown and it’s possibilities.  Maybe I’ll do one each way and compare.  I don’t know I’m all over the place on this.  More to come. 

[mmattockx]

I didn’t find my hide backings or snake skins applied with tb3 to be more flexible or rubbery.  Mine dried up quite good actually.

It isn't terrible or rubbery like contact cement, but it isn't rock hard like cured epoxy is. I am sure I could stick a thumbnail into mine and leave a mark years after they were done.

You could do a test piece with a thin board that bends easily and see how well the TB3 holds the sinew in place after drying.


Mark

[superdav95]

I didn’t find my hide backings or snake skins applied with tb3 to be more flexible or rubbery.  Mine dried up quite good actually.

It isn't terrible or rubbery like contact cement, but it isn't rock hard like cured epoxy is. I am sure I could stick a thumbnail into mine and leave a mark years after they were done.

You could do a test piece with a thin board that bends easily and see how well the TB3 holds the sinew in place after drying.


Mark

. Ya I might try that.  Thanks mark.  Another thought that is occurring to me is just to wash the stuff thoughouly first then pat dry it then chew it.  Maybe that will be more palletable.  Either way I’ll figure something out