Primitive Archer
Main Discussion Area => Bows => Topic started by: High-Desert on March 27, 2018, 09:21:51 am
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I just got my yew permit approved for this yew and have enough sinew stripped and wanted to try sinew backing a green stave. I've only read about natives doing this and was curious if anyone has done this, their results and their process. I'm guessing I should let it dry a bit, so it's not soaking wet,but I'm not sure. Any thoughts? Thanks
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(-P
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I see no real advantages, only several disadvantages.
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I sinew backed a green osage stave,, it turned out fine and killed some deer,
it did pick up more weight than a cured stave,,
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I'm wondering if the stave and sinew curing together would prevent cracks forming in the belly. I read, I think in the TBB, that older, more cured wood has a greater tendency to split in the belly. I'm also wondering if maybe the more green wood will take on more reflex.
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Would you sinew it and then wait a year, or whatever?
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If I had to, but it wouldn't take that long to dry with the bow nearly at dimension and the wood would be less than a 1/2" thick. Maybe let the roughed out stave dry a few weeks, then sinew back, so it's not so slopping wet.
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I would expect a green bow to gain more weight as it cures, it only makes sense. I would be concerned with warping and trying to correct it. I would also be concerned with the sinew drying way faster than wood causing it to "cup" the belly. I just cant see an advantage to it. I'm trying.
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Mike Yancey at Pine Hollow longbows does it all the time. I have roughed out 2 green Osage staves and heat bend them on a R/D caul for a couple weeks and then applied sinew and let them cure together for 6 months and finished them off. No problems.
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I might as well give it a try, nothing to loose except some time of it doesn't work out. Thanks everyone.
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I only did it once, ,, have read about others doing it,, I was in a real hurry when I did mine, and started shooting it after a few weeks,, so that is probably why it picked up so much weight,
but I had fun, and the bow did not fail,, probably not the best way to proceed,, shooting the bow with that short of a cure,, but back then I just wanted to shoot it so did,, (--)
put tape or finish on the belly and it wont crack as much
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I do it with juniper.
After cutting the juniper staves, I debarked them, sealed them up, I let them sit for a couple of weeks, then I rough them out, I get them floored tillered, add some reflex, then sinew back them.
I will let them cure for at least 3 months before I start working on them. Juniper dries pretty fast in this dry western air.
I do put duct tape over the belly to help with the moisture not escaping to fast causing belly cracks. I have had good success doing it this way.
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"I'm wondering if the stave and sinew curing together would prevent cracks forming in the belly."
Now I'm not a sinew guy, and I've never done it, but I'm having trouble visualizing why this would help prevent cracks in the belly. Because the green wood accept the increased reflex better ans the sinew dries? Reduced wood dries pretty quickly, and wouldn't reducing alone eliminate this?
It seems to me that if green wood were reduced to near-finished dimensions, sinew-backed and held in a form or something, it would probably be fine. But, I have also found that both drying wood and drying sinew do, or try to do, some unpredictable things like uneven drying, lateral warping or twist, reflexing more on one side, or one limb, more than the other, etc..
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"I'm wondering if the stave and sinew curing together would prevent cracks forming in the belly."
Now I'm not a sinew guy, and I've never done it, but I'm having trouble visualizing why this would help prevent cracks in the belly. Because the green wood accept the increased reflex better ans the sinew dries? Reduced wood dries pretty quickly, and wouldn't reducing alone eliminate this?
It seems to me that if green wood were reduced to near-finished dimensions, sinew-backed and held in a form or something, it would probably be fine. But, I have also found that both drying wood and drying sinew do, or try to do, some unpredictable things like uneven drying, lateral warping or twist, reflexing more on one side, or one limb, more than the other, etc..
The wood cracks by lateral shrinking of the back relative to the belly. Not anything to do with accepting reflex.
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Ah, ok. Thanks, Pat.
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Mike Yancey at Pine Hollow longbows does it all the time. I have roughed out 2 green Osage staves and heat bend them on a R/D caul for a couple weeks and then applied sinew and let them cure together for 6 months and finished them off. No problems.
Correct me if I am wrong, but I do believe Mike does not use hide glue, but rather he uses TiteBond glues.
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PatM- Is it lateral shrinking or moisture escaping too fast from the belly that cracks? I would not argue either way, but both a strip of tape or a coat of hide glue on the belly prevent this. I just finished a sinew osage bow. The sinew was curing 6 weeks before I tillered it removing the glue and it split from handle to tip. This is the first bow that split that long after sinewing. Like all the other bows that this happened to it shoots great but to others it looks broken.
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I've made plenty of sinew backed bows from green wood. They turn out good but like has been said, waiting for the wood to season is best. I like to shape the wood green with steam, but then let the stave season before backing.
One thing to keep in mind is to use compression or tension staves. Side split staves may warp as they dry after sinew backing.
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I always assumed it was the belly drying faster than the back because of the sinew layer. I tried the tape on the belly, which worked until I removed it and began tillering. Ever sinew moving to this desert environment, I've had every sinew bow crack on me, no failures, but it bothers me and I'm trying to find a method to avoid it.
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Probably a bit of both but ultimately if it's cracking after then the sinew matrix must still be shrinking in width.
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Mike Yancey at Pine Hollow longbows does it all the time. I have roughed out 2 green Osage staves and heat bend them on a R/D caul for a couple weeks and then applied sinew and let them cure together for 6 months and finished them off. No problems.
Correct me if I am wrong, but I do believe Mike does not use hide glue, but rather he uses TiteBond glues.
No. He rips the bark and sapwood off from green staves with zero regard to grain or violations. Then he slaps a crap load of sinew and TB3 on and leaves it for however long, then he makes bondo with TB3 and sawdust using it fill in the sinew job and sits it aside to dry. Then after its dried he rasps the bondo smooth and into a shape he wants. Then he adds rawhide over that and most often add skins on top if that.
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Mike Yancey at Pine Hollow longbows does it all the time. I have roughed out 2 green Osage staves and heat bend them on a R/D caul for a couple weeks and then applied sinew and let them cure together for 6 months and finished them off. No problems.
Correct me if I am wrong, but I do believe Mike does not use hide glue, but rather he uses TiteBond glues.
No. He rips the bark and sapwood off from green staves with zero regard to grain or violations. Then he slaps a crap load of sinew and TB3 on and leaves it for however long, then he makes bondo with TB3 and sawdust using it fill in the sinew job and sits it aside to dry. Then after its dried he rasps the bondo smooth and into a shape he wants. Then he adds rawhide over that and most often add skins on top if that.
Well...that oughta make em bomb proof!!!
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That belly cracking must be a pretty powerful force yet then especially in an arrid enviornment.Even enough to crack horn also on turkish bows I've read if below 30% humidity.I've been lucky I quess but will remember to use tape or something from now on especially if a lot of sinew over 3 ounces is used.Maybe putting on the sinew in stages will help with that too.A little at a time a week apart.
Personally I've sinewed quite a few bows with 3 ounces maybe the most overall.I usually do it in 3 sessions.4 to 7 days apart.Usually with dried wood too.I'm sure my area is more humid than yours but I've never experienced those cracks yet.Annoying I'm sure.I usually keep it in a cool place the first couple days is all for it to gel and set properly.Then out into a warmer area with a little air flow by it maybe.I keep humidity gauges around to monitor things myself.
Keeping it a cool enviornment at first a while to slow that drying down and even upside down[back to the floor] by the floor level in a more arrid enviornment like yours that is.Using a humidity gauge to keep it above 45% to 50% humidity at least in the beginning stages.Possibly in the bathroom??All things to slow that drying process down some so it does'nt dry or shrink so fast.
I'm wondering if you see cracks lengthwise on your sinew while drying also?Because it drys from both sides also.That can be a problem of too thin of hide glue used too.
It sounds like you know what your doing though.Good luck.
(-P
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Mike Yancey at Pine Hollow longbows does it all the time. I have roughed out 2 green Osage staves and heat bend them on a R/D caul for a couple weeks and then applied sinew and let them cure together for 6 months and finished them off. No problems.
Correct me if I am wrong, but I do believe Mike does not use hide glue, but rather he uses TiteBond glues.
No. He rips the bark and sapwood off from green staves with zero regard to grain or violations. Then he slaps a crap load of sinew and TB3 on and leaves it for however long, then he makes bondo with TB3 and sawdust using it fill in the sinew job and sits it aside to dry. Then after its dried he rasps the bondo smooth and into a shape he wants. Then he adds rawhide over that and most often add skins on top if that.
Well...that oughta make em bomb proof!!!
Something like that :)
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Mike Yancey at Pine Hollow longbows does it all the time. I have roughed out 2 green Osage staves and heat bend them on a R/D caul for a couple weeks and then applied sinew and let them cure together for 6 months and finished them off. No problems.
Correct me if I am wrong, but I do believe Mike does not use hide glue, but rather he uses TiteBond glues.
No. He rips the bark and sapwood off from green staves with zero regard to grain or violations. Then he slaps a crap load of sinew and TB3 on and leaves it for however long, then he makes bondo with TB3 and sawdust using it fill in the sinew job and sits it aside to dry. Then after its dried he rasps the bondo smooth and into a shape he wants. Then he adds rawhide over that and most often add skins on top if that.
Well...that oughta make em bomb proof!!!
Something like that :)
Talk about adding excessive weight😐
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J.W. Pearl answered your Titebond queastion.
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I think TBBI talks about belly splits after sinewing and the authors concluded it is almost never fatal as long as there is no grain runoff and that lateral shrinkage of the sinew causes it. If that’s the case I’m shocked a piece of tape helps...most interesting.