Sinew backing questions (pics added)

[ravenbeak]

I have just finished my first sinew backing job and am ready to proceed.  It has been drying for a week and I want to move onto final tillering but I am wondering about the durability of the backing,  As brushing it roughly will pick up the odd piece of sinew here and there.   I am planning on finishing the bow with tru oil and am wondering if it is worth putting a couple coats onto the back only to help protect the sinew while proceeding with tillering?
 thoughts? suggestions?  all appreciated. 

cheers,
Jamie

[Pat B]

First off I don't think 1 week is long enough for curing a sinew backing. I waited a month on each of 3 courses on the sinew backed bows I built. You especially don't want to seal the sinew until it is completely dry or it will rot.   Once dry Tru-Oil will be fine for the backing although if you applied the sinew properly and used enough glue(not too much) you should not have a problem with the sinew strands peeling up. You can sand the surface of the sinew smooth if you want too.      Pat

[ravenbeak]

thanks Pat, 

A month for each course hey,  wow.  I guess I'll wait atleast another week minimum.  Also,  I was curious about sanding the sinew smooth a bit,  you answered that one,

thanks,

[Papa Matt]

Did you wrap your sinew to the bow? I don't know how everyone else does it, but I would definately wrap it snug after applying it, with bark, cloth, something to hold it tight against the wood as it dries and cures, but preferibly that would allow it to breathe and dry at the same time.  In my opinion you should always wrap a sinew backing as it dries and cures and not take it off for at least 2 weeks.

~~Papa Matt

[adb]

Hey, Jamie

What kind of glue did you use for the sinew?

[Ryano]

Drying time varies a lot with your level of humidity and temperature. I would suggest putting it some place warm and dry for at least one more week before you start tillering again. Sounds to me like you didn't use enough glue if you have strands pulling up. Did you dip each bundle in the hot glue as you applied it? Did you soak the sinew in warm water first?

[leapingbare]

I am not a sinew expert but i have done a few,
 1st off the drying time depends on the type of glue you are using, The liquid hide glue takes for ever to dry = 1-3 months. I use the powdered hide glue and water and i put on a coarse one day let it dry for 24 hrs and although its not completely dry i have found that it is dry enough to apply the 2nd coarse and so on once i get the 3rd coarse applied i let it sit cure for a week in a dry place. Don't put your bow in a hot box to dry because the moister from the glue will evaporated and cause the inside of the hot box to be humid, i learned this 1st hand, after about 2 or 3 days of drying and once 80 or 90% of the moister is gone from the sinew i then put it in the hot box.
 Pappy was with me when i was doing my last sinew job and he suggested that i wrap the bow with a ace bandage, i was hesitant to try it i thought the hide glue would stick to the bandage but pappy was right and the bandage came right off and was the smoothest sinew job I'd ever done.
 So use the powder hide glue and let dry for a week or two, and wrap with ace bandage.

[Pat B]

Its not only the moisture in the sinew but the wood will absorb moisture also. I put a snake skin on an osage bow a few years ago and it was 2 weeks before the bow was back up to weight. It started out at 56# and after applying the skin the draw weight went down to 45#. 2 weeks later it was back yp to 56#. I have heard of others shooting their sinew backed bows a week after applying the sinew but that wasn't the case for me.     Pat

[TRACY]

I put all of my sinew on at one sitting with powder form hide glue and don't have any problems. I don't mess with tillering for a month. I try to air dry in the sun when time permits to cure the sinew. I don't wrap it because I think it is important to lower the moisture content and feel like the wrap might slow this process down. That's not to say wrapping doesn't work, just my rationale. There are many approaches to applying sinew, but they all require a substantial drying/curing time for the sinew to be effective.

Tracy

[Pat B]

Some of the old Chinese horn bows(I believe) would cure for 10 years before being stressed.

[leapingbare]

Another thing to consider when applying sinew to a wood bow is the natural oils in the wood, i know Osage has these oils and what i do is simple and primitive.  i take about 1/2 cup of wood ash and add water to it making a past than I apply it to the back of the bow and let it dry, than i wipe it off, you notice its done its job because the wood will change colors, like the bright yellow of fresh worked Osage will look like a piece that was worked a year ago.
 Another thing to do it surfice prep, take a hack saw blade and scratch the back of your bow before you apply the sinew.

[ravenbeak]

Thanks everyone for the advice,

This being my first sinew job took much longer than ever expected.  I didn't apply the sinew in bundles,  except at the end to build up the handle a bit,  but instead applied it painstackingly strand by strand.   I applied it in relatively thin layers at a time,  usually a day or two apart between applications,  and in total probably six or seven different sit down sessions of sinewing.   I would guess in total i put 12 hours into the process,  and remember commenting more than once,  "hun,  if i ever say i'm gonna sinew a bow again feel free to slap me in the head"

I used homemade hide glue,  The first three layers were from store bought rawhide chews boiled down by my dad,  at the time I thought it was pretty tacky stuff.  The last four layers were straight from the road kill,  boiled down,  much browner than the other stuff and way stronger.  I experimented alot,  with soaking the sinew first and then into the glue,  and also straight into the glue.  but by the end,  my process was to wrap the sinew in a damp cloth forawhile and then into the glue.

I didn't wrap the bow at all,  but during the last application I did do a few strands of sinew wrap around the tips to hold the ends down.

I look forward to posting some pics of it soon,  oh boy it's a different bow.  that's all I can say for now

thanks all,
Jamie 

[ravenbeak]

I'd like to share a couple photos of the bow i'm working on. 

With these traditional bows we're all addicted to I know it's all been done before,  but i'm hoping this one might stir the pot a bit. 

It's 60" tip to tip.  I pulled it on the stick to 40 lbs at 14 inches before the sinew went on.  Unbraced it sits at about 2 inches of reflex. 
Pacific Yew with reverse yew overlays,





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[Ryano]

What the ? 
Split limb self bow now I seen it all.....lol. 

[ravenbeak]

I was thinking the wind resistance of the limbs would be less with the backless design,  we will see.

the first sinew backed backless bow?