Sinew on an ALB?

[Canoe]

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

[Weylin]

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.

[Pat B]

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.

[PatM]

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.

[Eric Krewson]

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.

[PEARL DRUMS]

Hickory backing weighs more than sinew Im guessing. We have no problems gluing that to the back of ERC at 72" long?

[Badger]

      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.

[Badger]

  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.

[PatM]

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.

[Badger]

  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.

[PatM]

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.

[RyanY]

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.

[PatM]

 Ryan,
How many sinew backed bows have you made?

[RyanY]

Enough to know its too much work for a longbow. 

[PatM]

Hmmm, never saw a pic of a short one either.