Horizontal Cracks in Sinew

[StickMark]

Do I have a problem? 57" bow drawn to 16", with a goal of 24" draw.  Sinew reused twice.  I now know I have a lot of glue for this one layer, individual strands laid down one by one.  I won't do it that way again. 

Should I soak off the sinew, wash, and do as bundles with less glue? Bow is sized with one good layer.

[ohma2]

Appears to be the built up glue cracking.

[StickMark]

 Better to redo?

[StickMark]

I going to redo. I can do better than this; better bundles and less glue. Patience...

[Pat B]

Too much glue I think. On the next try dip the sinew in the glue and squeegee off the excess with your fingers and lay it down. By running the sinew through your fingers you not only remove excess glue but form a ribbon of sinew which will lay down flat.
Be sure the back is well sized before adding the sinew. I like to do this in 2 or 3 applications as soon as the previous glue jells I add the next sizing.

[StickMark]

When applying the bundles, the individual strands in the bundle have to be flat?  This part confuses me, and that's why I applied individually each strand, and with resulting too thick glue.
(I am assuming that I want thread like size, not the rather large, more flat strips I have used before.)
Or, running the bundle through the fingers flattens out the bundle enough?
Thanks for the help

[bradsmith2010]

you might get a better sinew to glue ratio,, but maybe just try it as is for now,, and redo on the next bow,,
I dont think it will cause it to fail,,it doesnt look bad to me,, I could be wrong,,

[PatM]

Too much glue and likely sub-par glue.   Use Knox and  put it  on cooler.

[StickMark]

Knox gelatin, food grade.  Got it.

[Pat B]

You want the individual strands to be small but each bundle you glue down can have multiple strands. As long as the sinew bundles lay smoothly and flat you will be OK. 
Like Brad said, leave this bow as it is and enjoy it and make the changes on the next one.

[bownarra]

Glue thickness is key as well.
Use 20 - 30% for 1st layer, 15% for all other layers. Size with 5 - 10%
To me it looks like a bit too much glue but it also looks like it was likely too thick.

[gutpile]

I use hide glue in double boiler.. size bow dip sinew ring out glue lay on back .. stack in brick like pattern first layer.. fill in spots on second layer... I then put a weight on handle of 25 lbs and let hang suspended to induce reflex while it dries.. about 3 months...gut

[StickMark]

Thanks for all the input.  I decided to redo the sinew job.  Learning to make it as perfect as I can is a goal on these sinew bows.  Thought about rawhide backing it, but I can wait a month to ultimately shoot it.  Tillering the bow,  it shows promise. I hoped to bring it to New Mexico on a trip, to stump, but would rather redo the sinew.  I will try the Knox gelatin.

Going to need a hunting bow.   Arizona's velvet summer season is a month away, and my favorite hunting bow develop some chrysals; apparently, piking, much re-tiller, and finally adding three layers of sinew pushed my bow and my knowledge  .  It is retired.

Going through my wood stockpile, and utilizing a wormdrive circular saw I had to buy for house project.  The sinew is only part of the journey into backings.  Trying hickory backing on other bows as well.  The summer season can be wet, and maybe a hickory backing will be better for rainy day hunts.

[Pat B]

A hickory selfbow should preform quite well in AZ's dryer climate.
 No need to back the sinew backed bows. Even though your backing cracked doesn't mean the bow will break. The hide glue still holds fast.

[StickMark]

I concur.  Looking at the bow, it is fine.  A draw weight at 43#, 46# will be where it ends up.  At that weight, I am good (want that 55# or 60#! and body just says "no way, dude."  Ishi, a West Coast hero, drew 45# on one and 45# on another.)

Just getting the fades to bend a little more on this stiff handled bow...
This conversation is great.  Like having you guys in the workshop...