Fire Hardening

[Burnsie]

I just watched a video of Clay Hayes making an awesome fire hardened hickory bow.  Got me wondering - as good as Osage is for a bow wood, would there be any added benefit to give it a fire hardening treatment? 

[Hamish]

I've never heard of anyone trying it with osage. Osage is denser already. It is also more susceptible to getting drying cracks than whitewoods. Osage also doesn't like to be bending at extremely low moisture content, as it becomes brittle in tension.

I don't know the scientific reason that makes the heat treatment improve whitewoods. I'm guessing it could be something like the air still in the wood cells, and vessels is heated out, the empty spaces shrink, and compress the wood, leaving more lignum for the same dimensions??? Or it could be some other sort of chemical reaction?

Denser wood species, possibly don't have as much air trapped in the cells and vessels, so there is less opportunity to compress, and therefore not as much change for  improvement to occur.

Pure speculation on my part. Hopefully someone with the correct knowledge will chime in soon.

[Robert Pougnier]

I believe that's a question for Marc St Louis.

I have zero experience with Osage, but have made many white wood bows. My understanding is that many whitewood species are great in tension but relatively poor in compression. Heat treating the belly of these woods helps to balance that out and creates both a safer and more efficient bow. I've had a few bows, mainly sugar maple and cherry, which have fretted badly after receiving a heat treatment. Other than that, heat treating them per MSL's instructions in TBB has helped me make bows that keep a much better side profile and are generally much more efficient and durable. It can increase poundage significantly too, and if you are worried about overpowering the back then you can back the bow with sinew or other to have a really durable and fast bow.

I think that Osage is one of those woods that is so dense and elastic that heat treating it would be likely more risky than beneficial. But I've never made an Osage bow so I could be totally wrong.