Homebrew PCBs

gk_impala wrote:
> Hello mumin,
> They work using a bi-metal element, which will bend more when heated, 
> and thus acting like a relay. Adjust the distance to the contact, and 
> it will switch on higher temperatures. They are just set on a fixed 
> range.


   Yep with liquid immersion, you should really be able to just bypass the 
switch and have the element on the full time.  Should work fine since with a 
large aquarium and small heater it'll basically be on the whole time anyway, but 
I think there is a limit of good return on the heat, after a certain point some 
etchants become worse in some respects like etching too fast with too much 
undercutting etc.

Alan