repeated dry heat bending harmful?

[Echatham]

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.

[Bowjunkie]

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.

[Echatham]

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?

[Bowjunkie]

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.

[Eric Krewson]

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.

[Echatham]

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.

[r-man]

would it help to moisten wood for bending?

[Echatham]

some people do rub oil or fat on to it.... but i haven't out of concern for finishing later

[Bowjunkie]

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.

[John Scifres]

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.