Thick D section HHB bows

[Marc St Louis]

I had some people ask me before about issues you can have when heat-treating thick bows of dense wood species like HHB.  One of the major problems is moisture even with well seasoned wood.  What happens is moisture gets pushed ahead and build up to the point where the wood will start to split from the pressure build-up.  I was lately heat-treating a thick D section warbow and decided to take a picture of this for posting here.  You can see a couple inches ahead of the heat-treated area how the wood is starting to swell.  At this point you have to stop and wait for awhile.

[Philipp A]

great pic Marc! Do you move the heat gun back and forth when over an area and how long do you usually stay in one spot?

[DC]

When you say wait for a while are you talking hours, days? Do you hold the gun farther away on thicker pieces?

[Marc St Louis]

Some people play the gun back an forth, I do not.  I give 1 spot 5~10 minutes, depends on the temp inside my shop.

I give it a day.  I hold the heat-gun the same distance regardless