Sinew Troubles

[SLIMBOB]

Need some help from the sinew guys...Applied sinew to an Osage back on Saturday night. This is the first solo for me on sinew backing. Couple of ride alongs and assists over the years. For preparation I sanded the back, scored the back with a hacksaw blade. Lightly but enough to see the marks. I then scrubbed the back with hot water and dish soap. I think the back was well prepped. In years past we degreased with lye in a bathtub, but a bunch of folks have said it’s not needed. I didn’t. So...I sized the back twice. Once Saturday morning and then again a few hours before I began. Knox Gel for my glue, 1/4 cup of water per packet. Heated only until it was thin and warm. I could stick my finger in it. Kept the glue warm, and applied the wet sinew after dipping in the glue. I did PatM’s method, so wrapped 3 times in a bed sheet and heated with a blow drier. Each time I let it gel before unwrapping. Finally, I wrapped in Vet Wrap and set in the sun for a few hours yesterday. When I unwrapped last night it has 2 areas that the sinew has pulled loose from the back. Not a big spot, you can feel it. It’s a low spot between 2 knots. I’m only guessing, but as the sinew shrunk, it lifted off the low spot. The other spot is on the other limb. You can feel that it is loose from the back.

1. Did I do something or not do something that might be the cause?
2. How should I deal with this?

[bradsmith2010]

 maybe putting in the sun,, made the glue liquid again,,
I would suggest just letting the sinew cure inside,,

[Pat B]

Can you separate the sinew over the spots it didn't adhere? If so put more glue in it(not too much) and more saturated sinew and, like Brad said, let it cure inside. Are you sure you didn't get fingerprints where it lifted?
 I use the same cleaning method you mentioned and since I started doing it that way I haven't had any problems with the sinew lifting.

[bradsmith2010]

also I wear latex gloves to handle the bow,, so I dont get oil from my hand on the back,,

[Badger]

  I had one osage bow I sinewed where the entire sinew came off in one piece. I resanded the back and glued it back down and it stayed. But it sounds like you prepped yours pretty well before applying it.

[bradsmith2010]

I like to use boiling water to rinse, I do everything  I can to prep the back,,I feel like that is the foundation for success with the sinew bow,, I feel like some sinew is greasier,, and may need to be washed as well,, most of my problems have come from back sinew, I did not prep well,,

[maitus]

Glue must gel in 15 minits. If You wrap it in to wet wrap ander the sun, it wont gel. I have never used wraping. I aplie sinew bandels wet and then give some reflex for drying. I have never failed. And i never wet the back. I aplie first time wery liquid hot glue.

[Bryce]

If you’re worried about a clean back, pouring boiling hot water over the back after a some light scoring is more than enough to get a good application.
If it’s a slight dip between knots you’ll probably just need to fill it with an small bit of sinew to level it off. Shouldn’t take much. I would also thicken the glue up just a tad; just let it sit in the double boiler for a hour or two till some of that moisture can evaporate. Like a light syrup.
If you can slide a small bundle of glued up sinew u see the current lifted part and just get it in there somewhat decently with a popsicle stick of something, then wrap it up and just let it be for a bit, should be alright. May not be pretty at the moment, but it’ll work. No worries amigo

[PatM]

You can't really put it in the sun until  it is  drier through the depth of the sinew.   You've dried the other layer while the  inside is only gelled and then likely turned to liquid again in the sun.

  How tightly did you wrap it with vetwrap?

[maitus]

Srry guys, but i have never seen any video and red any book where somebody wrap sinew and i have not done it by my self. Why to wrap sinew to leave many ugly stripes on to the back and what it gives to You? If the glue consistence is right, the sinew will never lift up. If i finish sinewing the second limb, the first limb is already transparent. The next layers will gel even more faster.. so why?

[PatM]

Smoother, tighter and more optimized glue percentage.  The same way modern composite materials like glass and carbon use the same idea.  It doesn't leave " ugly stripes" if done correctly.

 Many people have wrapped sinew backings in the past.

[Bryce]

Srry guys, but i have never seen any video and red any book where somebody wrap sinew and i have not done it by my self. Why to wrap sinew to leave many ugly stripes on to the back and what it gives to You? If the glue consistence is right, the sinew will never lift up. If i finish sinewing the second limb, the first limb is already transparent. The next layers will gel even more faster.. so why?

The wrap lines go away when done right. And it’s better that the lateral cracks and gaps when the sinew dries and shrinks.

[bradsmith2010]

I think I read Ishi put a wrap on for one sleep over,,
his method of glueing was a bit different than what most do now,,
I have done both with success,,

[maitus]

Smoother, tighter and more optimized glue percentage.  The same way modern composite materials like glass and carbon use the same idea.  It doesn't leave " ugly stripes" if done correctly.

 Many people have wrapped sinew backings in the past.

How the wraping can optimize glue percentage if You wrap geled glue ?

[bradsmith2010]

Maitus, the guys that do that,, heat the glue with hair dryer,, so it is not gelled,,I am not expert on the process,, just telling you what I have read,,