Heat inducing reflex.

[Morgan]

I am to a point on a hackberry stave where I have it bending on the short string at low brace and short draw length, and  I need to heat treat the belly. I would like to induce some reflex at the same time. Would it work to place a 2” block under the Center of bow belly up on a board and clamp the tips to the table then heat treat as normal with heat gun? Or would this produce greatly uneven reflex

[JohnL]

     Morgan,  I do that all the time.  It works just fine, as long as you're just looking for a hint of reflex, or "back-set".  I usually use a chunk of 2x4 under the back of the handle, clamp that down to the bench, then clamp the tip of each limb down to the bench, and stand back and look at the arc in relation to the bench surface, to insure that left and right are consistent.  If the gap is too short in one spot, you can slip a block of wood in there to raise it, or if the gap is too tall, you can put a clamp on that spot after heating, to pull it down even.  You only get about 1/2 of the block's height in reflex from this method.  A 2x4 is 1 1/2" thk, and I ended up with 3/4" overall reflex, after it was cool and un-clamped.  And most of what remains after shooting it in, is in the outer 3rds, where there's little bend. 

[Pat B]

You will get a more even reflex by clamping your bow to a form that supports the entire bow. You can make one with a 2x4 by cutting it into an arch of the reflex shape you want.

[Morgan]

Thanks guys. I didn’t want to make a form because I have no idea how much I want . Ultimately I want enough to offset any set I get to keep string follow at bay.

[Pat B]

My form induces about 3 1/2" of reflex(with a 2x4) the bow comes off after heating at 1" to 2" of reflex and the bow after being shot in at 1" of reflex to flat.

[Morgan]

Sounds good. I need to make some forms for that and recurves to play with.

[leonwood]

A form as Pat suggests is really easy to make and has another great advantage. You can also correct sideways bends to line up the string while you heat treat it. Two birds one stone thingy
I use it for that all the time!

[bjrogg]

I agree with Pat and Leonwood. I made two forms. One I use for bending my static recurve tips. Then I made another that is short enough to fit in between my recurve tip only on the limb. I marked the center and then put two mark on each limb of form evenly spaced and added about a inch and a half reflex. It was very simple to make and like Leonwood says  you can use to corect twists and side to side alignment.
Bjrogg

[DC]

One of Clay Hayes' videos is making a form for bending recurves. He laminated two pieces of 3/4" plywood and then cut the center out so he can put clamps anywhere. I was thinking of making a big one.