Electric Boil Kettle controller - Pulse Width Modulation

[MixnMatchBrew]

Found a cool gadget on homebrewtalk.com I'd like to put together.

I'd prefer an off the shelf item but it seems the frequency is the important thing for this.

Circuitry is not my forte. I can muddle through this setup but wanted some opinions on this design:
Pulse Width Modulation controller build. It will control a relay (SSR) which in turn will control the boil of an electric immersion element (or two)

Basically the same function of a Manual Mode on a PID controller

Link Here:
http://www.homebrewtalk.com/f170/pwm-sh ... ost3555908

[Jimmy Orkin]

This is an astable PWM circuit. It should work fine.

I would add an LED in parallel with the SSR so that you can visually see the on and off times.

I have all the parts except the SSR.