Backings

[DC]

I'm trying to understand when and why you use different backings. I'm talking about performance rather than rescuing a bow with a bad back. When and why would you choose sinew over bamboo for example?  Or vice versa?

PS I did a search and found a little info. Basically sinew a short reflexed bow and bamboo on just about everything else. What happens if you use bamboo on a short reflexed bow? Does it lift splinters on the boo?

[Pat B]

When I build a sinew backed bow I design the bow to take advantage to the elasticity of the sinew, ie. short static recurve or R/D design so I want the best piece of wood I can get for that application.
I think bamboo got popular because it is sexy looking. It does give good performance to a bow but to me it is just too reliable. I've seen too many boo backed bows lift a splinter or shred all together. Hickory will give you almost as good of performance with lots less work and a lot more reliability.
 Bamboo can be used in a short reflexed or R/D bow. James Parker has made short Asiatic horse bows with bamboo bellies and/or backs.

[gfugal]

I view backings as something to prevent the bow from breaking allowing for a more stressful design. I never understood backing woods with a wood that has similar properties. Like backing Osage with hickory or something like that. It would seem better to skip the laminate step and just leave it an Osage back unless it was violated or something. If you have dissimilar wood I can see it working better like hickory and ERC. Which puts the wood where it works best. Hickory is a strong and elastic tension wood and ERC has good compressive abilities. Therefore the combination can handle more stress than either could on their own. I've actually never tried hickory and ERC but it sounds like a good combo, someone who has should tell us if it actually works or not.

Other backings are usually much more elastic than wood (sinew, flax, linen, etc.) so they should help prevent the bow from breaking if you feel the design is overly stressful, considering the outer fibers handle the majority of the stretch/stress comparatively.

[Pat B]

I only back board staves with wood or boo. If a stave needs a backing for violations or very thin rings I use rawhide. Like I said above I plan sinew backed bows before I start the bow. It's never an after thought.

[BowEd]

Another reason for backing is to induce reflex during the glue up.

[PatM]

Generally you are matching your backing to the belly wood of choice. Also sinew allows you to not have to attain a flat surface.

There is a lot of leeway either way and people do every possible combination.

[gfugal]

Another reason for backing is to induce reflex during the glue up.

I only back board staves with wood or boo. If a stave needs a backing for violations or very thin rings I use rawhide. Like I said above I plan sinew backed bows before I start the bow. It's never an after thought.

Good Points! I guess there are good reasons to use woods of similar properties, depending on what you have.
Like PatM said you'll see every type of combination, and if they got it to work than it's its own evidence I suppose. 

[PatM]

Also the choice of backing a wood with a similar wood comes down to availability and the predisposition of the backing to grow in a manner conducive to cutting clear strips from.

So Hickory on Osage  is an example of that. Generally people are backing board staves or straight staves with a sub-par outer portion.

[willie]

Also the choice of backing a wood with a similar wood comes down to availability and the predisposition of the backing to grow in a manner conducive to cutting clear strips from.

I have used maple with good results for this reason, and birch also.

[arachnid]

Here's  good video that explains it
https://m.youtube.com/watch?v=PBOkMi53YwY