Originally Posted by jnortham
Being in the electric process heating industry ( www.durexindustries.com
semiconductor processing, chemical processing, plastics processing, aerospace and temperature sensing) I would suggest staying away from monkeying around with the LM555 type timers unless you want to spend more time building and troubleshooting circuitry instead of brewing beer. There are too many readily available, low-cost solutions unless you want to build control circuits for fun (indicative of a sick mind for sure).
Are you trying to modify an exisitng piece of equipment or are you scratch building one?
I completely agree about the difficulty and non-necessity of scratch building a 555 based control. Too complicated and I am concerned about what happens if it fails during a brew session.
On the other hand, if a light dimmer with the triac circuitry will work, it will be cheap and, if it should breakdown during a brew session, easy to fix. I think I have figured out a way to test the idea. I will just buy what I think is the correct SSR and wire it up with the dimmer on the control side and single light bulb on the output side. If I can control the brightness of the bulb with the dimmer and through the SSR, then I will be able to control the water heater element also.
This will be a new piece and, hopefully, the start of my all electric brewery.