|Etch tank bubbles at 51 degrees|
The multimeter is showing the temperature (Celsius) of the water in the tank, via the thermocouple in the tank top centre.
The water is heated by that white stick sitting vertically in the left of the tank - this is the heater - just two 30 ohm resistors in series, encased in heatshrink tubing.
The heater seems pretty effective. At 0.75A of current, I was able to raise the water temperature from 22 to 52 degrees in about 15 minutes, so it should be more than capable of maintaining the temperature of the etching solution, if it starts at the correct temperature. I'm driving the heater from an adjustable bench supply, so I'll adjust the current to find the equilibrium point is (or near enough).
Now, all I need is a project to etch...
|2||"FORMAT" 6x8" photo frames||$6.00|
|1||Small tube of silicone sealant||$8.50|
|1||Aquarium air pump (incl delivery)||$6.58|
|1||2 metre length of air tubing (incl delivery)||$2.45|
|1||30cm air curtain (incl delivery)||$1.96|
|2||30 ohm, 6 Watt wirewound resistors||$3.68|
|1||Length of heatshrink tubing||-|
|1||Length wire for heater||-|