Heat Bending Helpful Hints

[Eric Krewson]

As my stash of osage is depleted of straight, clear wood I find my bow making to be 75% straightening wood and 25% bow making.

I have turned some wood that would have been impossible for me to work with a few years ago into premo staves.

I have found that a good insulating wrap after you heat and correct your stave really lets the heat soak in and you get much better results. On a form I do it like this, the Tee shirt is over a woop-de-do I needed to remove.

   

If I am doing a propelled or sideways correction in a small spot I use my aluminum angle for a reflector to heat the stave up faster, make a correction and wrap the angle and stave together.

The angle stores heat and is probably 300 degrees after I heat the stave. By wrapping them together the angle transfers heat to the stave
and I get a much easier correction.

   

[Pat B]

Good ideas, Eric. On thicker jobs I will heat the wood and wrap it in aluminum foil for a few minutes and reheat it, them clamp. After the clamps are on I reheat the whole area again and wrap it back in the foil. I then let it rest at least over night before removing the clamps.

[razorback]

I heated a stave I had to put reflex in it and to bring the tips into alignment. I think the sideways correction needs to be done again. Can you keep heating an area until it fixes or should I bend it beyong the straight line and allow  for some return .

[Eric Krewson]

I over correct, some of my straighting is pretty severe. If I pull it into a straight line it always springs back and needs to be done again and again.

[Pat B]

I prefer to use the heat as little as possible but I have heated and reheated and reheated with no ill effects.

[dinorocks]

In your opinion, is it better to to use steam (I assume it is much more involved) then dry heat?  In my situation, I have a very big bend (hump so to speak) on one limb of a mulberry a stave I'm working on...if I only heat this area, I'm worried that I will harden the belly in this area and have potential issues with tillering.  Is it exceptable to heat the back of the stave?  

I heard that by applying Crisco to the belly of the stave, the heat is spread out (transffered) more evenly...I tried it and it seemed to work (although it may have worked just the same with the lard).

[2treks]

Eric, Do you ever get a reflection burn with the alum angle in place? I have scorched the back from the heat bouncing off my cull.
 I also will over correct and try to guess how far it will want to spring back. I also like to take the stave as close to bow dim.as I can before heating. Meaning I get rid of as much wood as I can first.seems to hold better.
  Dino, I think you will not use as much heat for taking out your hump as you will when you temper or harden the belly. so your straightening should not cause you any problems. I would think that heating the back directly would be worse. also you can dent the soft hot wood on the back.
Chuck

[Eric Krewson]

I have over heated a place and gotten a little light tan on the angle side but if I keep my gun moving I don't have a problem.

[Pat B]

Dino, I use olive oil and a heat gun. Any oil or grease, lard, etc will work. I know others that don't use any oil at all for dry heat.
  I like using oil. As you said, I believe it helps to hold the heat longer and it helps transfer the heat evenly and prevents scorching. This is for bending and straightening. When I temper a belly I use no oil and scorch the wood on purpose to a chocolate brown color. Heating to bend and straighten is one heat treatment and tempering is altogether different...although, you can straighten and bend somewhat as you temper.
  Some boil or steam when they do drastic recurves but I don't like the idea of adding moisture to already dry wood. It you use wet heat on dry wood protect the wood from moisture with shellac.