Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Thanks for the response JP, Interesting the sides started to melt at 150ºC - I'm sure the single temperature version is different than the older dual temperature version. I guess I'd better be VERY careful to make sure this one stays good.

I remember reading somewhere the circuit on the single temperature version has some type of resistance sensor - the dual heat has a ON/OFF thermal switch. As you said, the temperature switch opened around 120ºC but the temperature would keep coasting upward a few degrees.

With the temperature controller I built I have the heat to start tapering off at 10ºC before setpoint, with zero heat at setpoint. Then the temperature will only coast 1 or 2 degrees upward before falling back. As temperature crosses setpoint, the controller starts slowly adding heat to prevent sudden changes. With this setup The temperature usually stays within ±3ºC of setpoint.

I'm not sure what the actual copper temperature is, but at the metal where the temperature sensor is mounted, 155ºC gets very good toner transfer.... just where you say the plastic starts to melt on the single heat GBC laminator. Epoxy forms should hold very nicely.

Take care and still having fun.

Ken H>