Ring orientation reversal on boardbow??

[Chuck Hoopes]

Thinking out of the box here.  What do you think?  Situation: I have made several hickory board bows, orientating the growth rings so that the outer rings form the back of the bow. In other words the top of the arch of the cirle of the ring.

Alhough hickory has very good tension strenght, I have found the compression strength to be just fair.  Iam thinking that since I back these bows anyway, and am not concerned about breakage, why not reverse the ring orientation.  This way the top of the ring arch forms the belly of the bow. My thinking here is that the compression strength would be increased- similar to the princple of the Roman Arch.  Are these just the musings of a Madman?      Has anyone tried this?  What do you think?

[trashwood]

I think you are going against the natural phyics of growth rings, having the crown of the stave as the belly but ya never know till ya try.  I have used quarter sawn hickory boards backed with flat sawn hickory backing that showd more to resistance to compression.  One of the biggest things regarding hickory is ya got to keep it's mositure content down even when bow is sealed well.

rusty

[Jim now in Kentucky]

In TBB I, there is a discussion of "backward" bows. These were made with the outer ring the belly and the core side of the stave for the back.

Ancient examples of that design have been found, so there is a precedent. I say give it a try.

Reparrow man

[George Tsoukalas]

Me too. It won't matter either way. Jawge

[trashwood]

well; there ya go the expert has spoken.  Lets us know what you find out  

rusty

[Jason Jelinek]

I've heard you can increase the compression elasticity of whitewoods by slightly charing the belly with a heat gun or fire.  It doesn't work as well on osage since it is already elastic in compression.  I believe the charing keeps the very outer cells of the belly wood from absorbing moisture as quickly.

Marc St. Louis has been doing this for years with success.

I want to try this with White Ash on an ELB design in the next few years.

Jason

[Chuck Hoopes]

A few weeks ago I took a heat gun to the belly of a hickory flat bow.  First time I had ever tried to increase compression strength this way.  I basically toasted it a golden Brown. - Result, bow took a 2" set. (like 2" of string follow)-- so if I gained any compression strenght, I figure it was negated by the set.  I really don't see how you can rapidly remove moisture from one side of the limb, and not have this occur.  I can see how a heat gun would be handy for creating reflex, but am stymied at this point to see how its going to do you any good on the belly.  I must be missing something here -- anyone have an answer?

[Pat B]

I have heat treated the bellies of hickory, ash and Hophornbeam, all with good results. My last 2 osage bows I heat treated the bellies and it worked very well also.
   When heat treating(tempering) you want to start off with very dry wood. It is not a method of drying wood but of increasing the compression properties of the wood.
   If you read Marc St Louis' chapter on heat treating in TBBIV he explains the process and the results.  Pat

[Pat B]

...oh! and I don't believe you will increase the compression strength of wood by flipping it over. It is the same wood with the same compression and tension strengths, no matter which way it is flipped.