Friday 5 April 2013

Heat Bend

I spent ages thinking about how or if I was going to straighten the Yew stave.
Like many things I opted for a compromise. I couldn't work out how to simply remove the huge reflex dip and the deflex tip at the same time, so I decided to correct the deflex tip giving a symmetrical but quirky stave.
It was about 10:30 in the evening when I suddenly though I'd give it a go. I knew that I'd be dreaming about it otherwise!

You can see how I clamped it up and how the belly has been darkened by the heating. It took nearly an hour to do that one limb. There was a fair bit of heating before I pulled the tip down. It was pulled down slowly using a G clamp as I was heating and I put in a bolt to hold it once it was right down (bottom right corner of the pic).
I used an offcut of wood clamped to the side of the limb while heating to try to stop the hot air getting to the back of the bow.
I still have a lateral bend to correct, but fortunately, that's on the other limb.

Hmmm, I spent some time jigging up the other limb to do the lateral bend, and I'd even started heating it. Then I thought, if I'm bending it sideways with the back of the bow cold I'll be straining the sapwood and back of the bow, probably better to steam bend the lateral bend as it will heat right through the whole bow. The heat treating of the belly will have to be done afterwards with the bow clamped to stop it springing back. So you see, plenty of thought has to go into a relatively simple process.

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