Heat bending

[DC]

I want to bend a handle for string alignment and use steam for the initial bend, then lock it in with dry heat. With steam you usually have to over bend to allow for springback. If I'm going to lock it in with dry heat do I leave it in the over bent position to dry heat it or do I get it to the correct position and then use the dry heat? Is it better to heat the compression side or the tension side or both or does it matter? Probably both hey.

[Dances with squirrels]

I don't buy into that 'lock it in with dry heat' theory. The only reason I would follow the steam correction with heat from the heat gun would be if something happened to slow my work while making the correction and the stave cooled down a little from the steam heat, I may bring the temperature back up with the heat gun while still clamped in position.

Why not just correct the handle area with dry heat to begin with? I've done that many times.

And btw, wood springs back with either method.

Heat all the way around. Overcorrect 5% or a little more.

I'm going to steam as many green elm staves as I can today.

[DC]

I tried just dry heat on the handle, slowly, all around and it didn't move. Yesterday I used steam on the handle and bent it a lot. Twice as much as it had to go. I moved the tip over a foot. When it cooled I heat treated it to about 400° and let it cool. When I unclamped it it sprung back about 6". So I'm pretty close. Now I have to wait and see. The first limb I did a couple of days ago seems to be holding so the "locking it in" seems to have worked. We'll have to disagree DWS

[Dances with squirrels]

If it sprung back 6" afterwards, it didn't 'lock in', not to my way of thinking anyway. Yep, guess we disagree.

Time to do get one out of the steamer....

[bradsmith2010]

yes I think the dry heat,, in the bent past postion, I think you did that,, sounds like you making some progress,,
   if you get the bow to shoot,, whatever you did worked,, please write it down,, so 10 years from now you remember how you did it,,,,,,,

[simson]

This is how I do:

I use the hg in 95% for string alignment, or one limb is really heavy off (more than 30°)
1. Measure how much the string is off: Tie a cord on one tip, center at the handle and measure how much you're off at the other tip.
This is exact the distance you have to correct.
2. Now put the bow in the vice, so that the wanted limb movement goes downward, hang on some weight (2# or so). And now measure the distance from tip to floor.
3. Heat the portion where you want the bend and watch the tip movement downwards using a yard stick. When reaching the exact distance stop heating and let it cool down.
4. Let the bow with the weight for some hours in the vice.

Result is the exact correction, no overbending needed.

Good luck

[Dances with squirrels]

I make many corrections that way too Simson, though not all of them. I use more weight though, up to eight pounds. After I figure out how much movement I want, I like to stand a locked tape measure up on the floor so that when the limb tip moves down and is flush with the end of the tape measure, I stop heating.

But it all depends. How much weight or clamping pressure to use, which heating method or jig to use, and how much spring back to expect depends on sooo many factors. There's no 'one best way' or 'best advice' when it comes to this stuff. Each circumstance and stick of wood comes with its own needs and variables. You just do what you gotta do. Our best bet, imo, is to experiment and gain experience and confidence with a variety of methods.

[bradsmith2010]

if you have studied Simsons bows, you can see the advice he is giving,,,is sound,,

[Dances with squirrels]

I didn't say it wasn't. How about this... how about I just go back to doin it instead of talkin about it...

[Hawkdancer]

Nah!  Keep doing both!  That's how the rest of us get enough information to proceed! . The weight method seems to be a good idea!
Hawkdancer

[DC]

That's how I do it if there isn't that far to go. When I first tried it with this one I had to put about 10# on it to get it to move and then it sprung back to almost where it was and then after a couple of days it went back the rest of the way. I've never seen anything like this before.

[bradsmith2010]

maybe it will resist taking set ,,,the same way

[Marc St Louis]

I always heat on the compression side  when I can, no chance of tension failure

You can have virtually zero spring back when using dry heat to set the bend after steam-bending.  You will always have some spring back without

[Dances with squirrels]

I heat all the way around. Never had a tension failure due to a heat correction... but I ain't in no hurry.

[Dances with squirrels]

Too many generalizations flying around here.