Heat Treating the Belly

[YosemiteSam]

I've heard of some folks heat treating the belly of board bows.  Where in the production stage is this done?  Before tillering or after?  And is this best done with a heat gun (moderate heat) or a blowtorch (high heat)?

[Pat B]

I usually wait until I get the limbs bending pretty well, usually at first brace. At the same time that I temper the belly I also add reflex and remove any unwanted twists or bends using clamps and wood wedges where needed.
 I use a heat gun, set on high and hold it in my hand about 2" above the wood surface. You only want to temper(heat treat) the belly side and not the back or sides of the limb.
 I first clamp the handle to a reflexing form, back of the bow down and start heating at the fades and work out the limb about 6" at a time until the wood gets a chocolate brown(some woods brown better than others) then clamp and move on to the next 6", coming back over the previous section. I continue to work out that limb heating and then move on to the next limb. After both limbs have been tempered and clamped I go over both limbs again then let the bow rest for a few days to rehydrate before stressing it.