working on a stave with a good bit of personality, i will get some pics later, but its required a rigorous round of straightening with dry heat... and really needs a little more. are there any detrimental effects of heating and bending the same area more than once? talking about osage by the way.
No. It can be done a handful of times in the same area, so long as you're careful not to overdo it each time. My heat gun is one of my favorite tools.
good to know. thanks Jeff. it sure is miraculous what what osage can do with a little heat. how do you know or define overdoing it?
Well, for one thing, I've never had to heat it until it changed color at all to make a bend... even when recurving tips or heating and bending thick handle sections. So I guess you could say scorching it is going too far. Besides, scorching the wood on the outside doesn't mean it is adequately heated on the inside, and since wood is a poor conductor, it takes time for the heat to penetrate. I generally heat it from all sides for a few minutes from 6-8" away, moving slowly, but always moving. Gradually, as the heat soaks in, I get closer and move faster, and continue to heat just until it's too hot to hold, maybe give it another minute more if it's a thick area.... and make the bend.
Another tip; After you finally get everything corrected the way you want, put your bow aside for a couple weeks to let it rehydrate. If you rush right into a finish bow right after a bunch of heat correcting there is a good chance your bow will be too dry and crack.
I had this happen to two really nice snake backed bows I made for friends. Each bow had a dozen or more corrections, lots of heating. I corrected one day and finished each bow the next, both cracked a limb shortly after I gave them to my friends. Pretty sure extra dry wood was the culprit, lesson learned.
noted. this stave was at 8% or possibly lower when i got it, so i have to be extra careful. very hard to wait though... since i have had the whole week off. im gonna get it right up to the tillering tree and let it rest i suppose.
would it help to moisten wood for bending?
some people do rub oil or fat on to it.... but i haven't out of concern for finishing later
Randy, generally, if my bow wood is dry, I don't care to add moisture to it if I don't have to. Some impressive bends can be made to dry wood with dry heat. I have never applied oil, fat, vegetable shortening or any such thing to a bow prior to bending and never had a problem.
I have moistened wood after a particularly aggressive bending or toasting session. But I still give it a week or more to come to equilibrium. I have no empirical evidence that this does anything, just an intuition. It hasn't hurt though.
Moistening raises the grain so I don't get the back wet, just the belly which is going to be worked anyway.