Ok so everyone has a different method to heat treating what is yours?
Personally I coat the belly of the limbs in cooking oil and then use the heat gun at the highest setting still the limb turns a nice golden. Typically i hold the gun about an inch from the limb. I usually heat the middle of the limb for a bit longer since that is where my limbs tend to fail if they are going to. Depending on how long i had to heat the bow i then allow it to sit for 3 days about in a humid location and sometimes will lay damp paper towels over the limbs.
I follow the directions in TBB Vol 4 with the exception of the spruce gum / turpentine mix he uses. Not many spruce trees in my area. I use a mixture of turpentine and tung oil finish about 50/50. Have only done a few bows, so far it worked well.....Dan
When I use oil and heat it is for bending or straightening. When I want to heat treat(temper) wood I don't use oil because I want the wood to scorch. This hardens the wood and makes it less sensative to compression stresses.
Each wood scorched differently. I try to get a nice chocolate brown color as I move out the belly of the limb. I use a heat gun and hold it about 1" to 2" above the belly and move it back and forth over about a 6" area. When that area is "cooked" I move out another 6" but continue to heat the previous area. When all is done I go over the entire limb getting it hot then let the bow(or stave) rest for 3 to 4 days or more depending on the R/H at the time.
Lately I have been using a torch to scorch the wood for tempering it without oil. I am in the process of building a lam oven though that will cook the entire lam at once in an attempt to ensure an even temper throughout the entire length. I am not sure if this has been done before or not, but I am going to try it anyway. I am aware of a few fly-rod makers that do this and they have had great success with it.
There was an article in PA Magazine years ago about tempering boo for bows. Three different guys with 3 different techniques. One used a propane torch with a rosebud tip(like James Parker uses), I don't remember what the second one used but the third one used his buddy's full size pizza oven. All three methods worked well for these guys.
I have only tried on the current bow I am working on, and I used wood coals to some success. But found the exhaust from a diesel generator worked best.
Greg Harris, was one of the folks Pat is talking about. I think he was in Washington State.
He used a toch tip like used for burning weeds or thawing ice to temper his boo.
Howard wrote of using a stove pipe, with a torch in the end to heat temper, cure his bows.