Primitive Archer
Main Discussion Area => Bows => Topic started by: Canoe on February 17, 2014, 12:36:15 am
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Howdy Group,
Yesterday, I was at a Trad event (in Madison, WI). Anyway, while there, I spoke with a vender who was showing me some of the bows he made. (He was selling knives).
His bows were ALB's and they were backed with sinew.
So, is that a valid option? I'm thinking sinewed bows are supposed to be shorter, like plains Indian's bows. And, I've thought sinew isn't for damp climates, like in Wisconsin. What do you all think?
Thank you all for your input.
Canoe
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Sinew backing is generally used on shorter bows. It isn't generally needed on longer bows and just slows them down because of the added mass. Maybe he does that to make sure his bows are super durable for liability sake. Sinew is effected by humidity and the bow will lose some draw weight in damper weather. I live in Portland, OR and I know guys with sinew backed bows. They typically don't use them in the winter months when it's wet.
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To get the benefits from a sinew backed bow the sinew need to be stretched and a longer bow can't do this. It would make a safe backing for protection but the physical weight of the sinew/hide glue would rob performance.
You can deal with humidity by storing the bow in a controlled environment like inside your home with heat/ac.
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Why can't a longer bow stretch the sinew? Just reflex the bow before applying the sinew and draw it further.
This is a recently emerging myth that needs to be analysed a bit more before it becomes dogma.
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As I understand it, sinew adds a bunch of weight to the limbs, sinew backed bows over 62" in length have so much added limb mass from the sinew that the extra weight negates the enhanced bow performance of the sinew. Don't know if this is a fact but as a proponent of low limb mass bow I can see that this might be the case.
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Hickory backing weighs more than sinew Im guessing. We have no problems gluing that to the back of ERC at 72" long?
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I think the deal with sinew is that it needs to be a larger portion of the limb thickness to be effective. A short bow has thin limbs. When sinew is thick it adds to the draw weight and actually relieves compression strain on a bow because the sinew does the stretching instead of the belly compresing. On most all wood bows the tension side of the bow barely stretches and all the elasticity is used on the compression side. Pn longer bows very elastic things just don't work out that well. We need less than 1% elasticity in a bow, sinew is something like 10%, if it is nnot adding appreciably to the draw weight we really are not getting the benefits to outweigh the extra mass.
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Pearl, a nickory backing is probably doubling the draw weight and it is much less dense than sinew. Sinew might just add a few pounds.
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Sinew is heavier than Ipe. You can still apply sinew in a way that minimizes the mass and maximizes the stretch. A sinewed longer bow should be narrower and thicker. The sinew should only be on the bending portion of the limbs.
Lukasz posted a sinew backed Yew longbow that had fantastic performance.
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Pat, an elb has a much larger bending radius than a stiff handled Alb. If the sinew he used on the elb was not adding significant draw weight my quess is that it did not contribute that much to the great performance he was getting. I don't really know what the hsyterisis factor of sinew is but assuming it is lower than wood the only advantage would be in less work done in compression, this where wood bows has hysterisis. The only difference in how fast something springs back in any material is the amount of hysterisis it has.
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The larger radius would mean it is getting stressed less than an ALB. It certainly doesn't seem like his bow was slowed down by the sinew as the naysayers would have us believe.
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Even if sinew added a little performance to a longbow why bother? Very well performing and safe longbows can be made without sinew and no sinew means none of the work to prepare it, put it on, and wait for it to dry out. An all wood bow is far simpler to make. Save it for the shorties.
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Ryan,
How many sinew backed bows have you made?
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Enough to know its too much work for a longbow. 8)
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Hmmm, never saw a pic of a short one either. >:D
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To get the benefits from a sinew backed bow the sinew need to be stretched and a longer bow can't do this.
A bow with a flat or deflexed profile can't do this. But what if you reflex the bow to the point that it does stretch a good deal to reach full draw?
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I make a lot of short and asiatic bows but for target archery I love longbows , I shoot in many traditional archery tournaments. Actually I use classic shape D 50 lb english longbow - Ipe/maple/sinew . Im very pleased . Bow have very smooth draw. It is no so fast like Ipe/maple/bamboo but extra speed bows make me nervous on tournaments :). 40 gramm sinew + 40 gramm glue is enough for normal longbow , 80 gramm it is not very heavy backing .
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Pat, why is it that every time I make a post contradicting you it comes down to what kind of bows I make? Sounds a little silly. As if my argument were any less valid. ::) I think everyone can agree it takes a lot more work to sinew back a bow than to make one without sinew, regardless of performance.
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Because you need experience to have a valid opinion.
The time factor argument is not really relevant to enjoyable hobbies.
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Sinew definitely is a lot of work, but I enjoy it for some reason :)
I have a 62" buckthorn decrowned stiff handle bow I am working on.
Limbs are 26.5" to tip from fades so even though it is 62", wouldn't it still benefit from sinew? Especially if I stopped it 3-4" from tips?
And, would I need to sinew over the handle or could it be very light over handle?
Seems like most sinew bows I see are bendy handles?
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I may not have posted a sinew backed bow on here but I have cleaned, shredded, and backed a bow that I have in the works and have not yet taken the time to complete. I know how much work it is and I know I definitely wouldn't want to back a whole longbow with the stuff when I know I can make a great bow without it. This is of course my opinion but time and effort are things everyone considers when making a bow. So lets see some of your long sinew backed bows with their amazing performance. I guess if you haven't posted them on here then your argument is invalid. ;)
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Because you need experience to have a valid opinion.
The time factor argument is not really relevant to enjoyable hobbies.
I don't know Pat, I believe you need to be intelligent enough to have a well grounded theory to have a valid opinion,
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I may not have posted a sinew backed bow on here but I have cleaned, shredded, and backed a bow that I have in the works and have not yet taken the time to complete. I know how much work it is and I know I definitely wouldn't want to back a whole longbow with the stuff when I know I can make a great bow without it. This is of course my opinion but time and effort are things everyone considers when making a bow. So lets see some of your long sinew backed bows with their amazing performance. I guess if you haven't posted them on here then your argument is invalid. ;)
Sure I have. Is a 64 inch bow not long? Are you actually now saying you haven't finished a sinew backed bow? I don't need to see pics, just asking.
I certainly don't consider time a factor. Especially when that time is worth it, and it is with sinew. You will see that one day too. ;)
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Even if sinew added a little performance to a longbow why bother? Very well performing and safe longbows can be made without sinew and no sinew means none of the work to prepare it, put it on, and wait for it to dry out. An all wood bow is far simpler to make. Save it for the shorties.
That's pretty much how I see it Ryan. I have no doubt that it is feasible, I just don't see it as logical. Sort of like making a bow using only sandpaper. Could it be done....absolutely. But why? I can't see the potential for net gain being substantial enough to justify the extra effort. Just my .02 . Josh
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Even if sinew added a little performance to a longbow why bother? Very well performing and safe longbows can be made without sinew and no sinew means none of the work to prepare it, put it on, and wait for it to dry out. An all wood bow is far simpler to make. Save it for the shorties.
I've only made 1 sinew backed bow. It was classically short. However, I agree with ryoon... why bother making a long bow sinew backed? Longer bows will perform perfectly without it.
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It comes down to what you want versus what is possible.
When you go by what is possible with sinew, you don't know until you know.
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There is reason sinew backing on lonbow - string follow. My after few tousend shoots and many hours stringin have perfect stable, straight shape after unstringing.
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Majority of cases for sinew on a longbow is pointless,and we all know it regardless of how much experience one has...and I think some folks here have different opinions and definitions of what constitutes as a "longbow"....
@Lukasz....I've made several unbacked longbows(bows over 68") that retain wonderful reflex or still straight after many shots and hours of string time,and made from woods to ash to osage....if desiring a straight profile or retained reflex with a unbacked longbow is your goal then just simply temper the wood good....now you have nice retained reflex that will hold without the dog weight of the sinew..
IMHO if wanting retained reflex in a longbow the best ways is to just temper it into the desired reflex,or just make it a laminate bow with a boo or wood backer
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Unlike some others I'll show an example as a case in point :-X ...lol :laugh:
I've been shooting the snot out of this bow exclusively(shot it for an hour last night too) and its still retaining over 4" of reflex at rest...this bow is unbacked...now someone tell me why this bow needs the aid and benefit of sinew when already holding a wonderful semi high reflexed profile without it? BTW this is the osage myth bow for those who don't wish to click on the link who have already seen it...this is just one example..I've made others,and I know other folks out there have made wonderful straight to semi high reflexed longbows without sinew...its just not needed
http://www.primitivearcher.com/smf/index.php/topic,44033.0.html
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Im going to weigh 15 back straps and an ample amount of hide glue when I get home. 15 straps would easily do a few layers on a 64-66" ALB. I want to know just how much weight it adds. Im also going to weight rawhide enough to cover the same bow since we are talking dead weight. My first sinewed bow was 63-64". "Too long" as they say.
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The whole point of making a longbow or longer bow is that its safer and doesn't come as close to exceeding the woods limits...in general and when all is equal a longer bow is faster and a very efficient weapon if done right...efficient enough for the majority of most archers....so why add sinew to something that's already a good thing? Sure ya can,but why? A shorter sinewed bow needs added setback,reflex,or recurve to be able to shoot on par with a good longbow,and to overcome the shorter bow is slower rule...you would have to pull a sinewed alb into near or more than 10" to get he benefits of sinew IMO...and when ya do that to an already long and narrower design your gonna possibly run into some stability problems,and a finicky tricky mess to tiller and tame,not too mention much the extra time involved sinewing it,and ya might have to make it wider than a self bow to compensate for stability issues adding even more mass cancelling out some or most of the benefits...the whole point in archery other than flight shooting is HITTIN YOUR MARK,and not speed speed speed,fps fps fps performance etc...and I see a lot of folks get blinded by that and thinks that is what makes a great bow,and forget all the other ingredients of a bow.....well I disagree....you can get the same results without sinew on it,so why? Just don't make sense to my lil pea brain...
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That is a great idea Pearl, and I am interested to hear the results. I'm not taking any side yet on this one. As someone who has messed with sinew only a few times on short bows, my first reaction is to think that longer bows wont benefit enough to warrant the trouble. But, as PatM stated, the trouble factor is a personal thing. The only question should be can you get a net benefit from sinew on a longer bow. Pre-stress the sinew enough and you might. PatM's method seems to squeeze the excess moisture out more than the way I have done it, so diminishing return but possible, maybe. All of blackhawks points are good ones, but may not address the single question. All other factors aside, can you get a net benefit? Open minded here.
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Slim what's your definition of a net benefit? ...define it please...if its only a 3 more fps and a harder to handle bow then is that a benefit? Your definition might be different than mine...mine is would it help me be a more accurate archer or not?
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Peace of mind never hurt anybody.
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Peace of mind never hurt anybody.
Some may and I know do think that,and that's fine....but IMO if that's the case use rawhide...much easier and a heck of a protection
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I'm with you on that Blackhawk. Pure speed is of less value to me than accuracy by miles, so I agree with you there. By net benefit I am strictly speaking about net cast per pound, nothing else. If there is a net increase, then it would be up to the builder/shooter as to whether it was worth it.
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I think the term alb..aka american longbow needs to be defined here,or otherwise there could be lots of misunderstanding going on here....some are talking 62-64" and to me that's not a alb,unless your 5 feet tall and draw 24"....but were talking an american longbow here..not a flat bow etc....and most albs were 68" on average in length with normal length handle sections...so unless your making a 68" bow with a two feet riser area your not gonna need the sinew....
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If we define it that narrowly, then you will undoubtedly be right, in my opinion. But open the parameters up some and that may change it. I am working on a 68" Blackhawk inspired holmie. 8 inches of stiff handle and 10 inch levers so 20 inches of working limb. Could this bow benefit from adding a sinew backing? I know that changes the argument a bit by reducing 20 inches that wont get any sinew, but it represents my point. I just think it is an interesting question that should be explored.
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Since I've been there done that a thousand times slim I'd say any benefit you'd get from it would be to minute for me personally to sinew..because I know if done right(key words) that design will do very well without the sinew..a few more fps on a bow that already should shoot easily in the mid 170's fps doesn't need it IMO,and doesn't warrant the troubles and downsides of sinew..although sinew is a great thing when used right,and I'm not bashing it or saying sinew is a waste of time n effort to do cus its not.....BUT I just don't see a whole lot of strong enough reasons to sinew in a lot of cases and this is definetly one of those cases to me...
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I agree totally. Let's face it... sinew backing a bow is a lot of work. I would never consider sinew backing a longer bow that already performs at it's peak. Why bother?
To me, it would be like putting an expensive set of high speed rims and low profile tires on a Ford Escort. What's the point?
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The only real fast bows I have tested that were sinewed were bows designed around the sinew, meaning the design could not be pulled off without using sinew. A short reflexed bow can be built at lower mass using sinew than without. I have also used it myself on some plum bows where I only had 1" of width to work with on 60" bows and got decent performance out of them but nothing earth shaking. I see no benefits on longer bows. Woods like juniper, wrc, and low elevation yew might be good candidates to use sinew on slightly longer bows.