Subject: How to fabricate a bimetallic spring

I have an idea on building an automatically temperature controlled smoker/BBQ 
that would utilize a device to control the temperature from the fire box to the 
cooking chamber--hence, a coiled bimetallic spring. I've searched everywhere to 
find the construction. The most common metals seem to be brass and steel. But 
how to assemble together--attach only on the ends, or completely around the 
edges, should the coils be curled first and then attached together or attached 
together and then curled ???? Does thickness of the metals affect response 
time, torque and sensitivity? I searched your site and only found something 
about circuit breakers. There are lots of smokers but all have to be closely 
monitored to maintain a certain temperature. I think I can build a 
better "mouse trap". Thanks

Re: How to fabricate a bimetallic spring