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Fabrication of the Fish Tank Heater
The leads of the heater resistor should not protrude far beyond the edge of the heat spreader. The heat spreader provides some protection for the leads. From this location, you can eye-ball the location of the screw hole, or you can mark the center of the hole with a pencil.
Prepare to Drill Pilot Hole
Mark the hole location with a spring-loaded center punch.
Press down on the punch until the spring snaps, leaving a round dent in the surface of the heat spreader.
Drill the pilot hole for the screw
Secure the heat spreader in the vise before drilling
Remove the burr on the side where the drill bit exited
Attach the resistor to the heat spreader
File the point of the screw
Solder the extension wire to the resistor
Add heat shrink to the resistor leads
Verify the heater resistance before sealing the heater
Locate the heat spreader in the middle of the large shrink tubing
STOP HERE: Ask the instructor about adding the sealant to the wires before the heating the heat shrink.
Use a heat gun to secure the end around the wires first.
Do not heat the heat shrink tubing until the instructor adds sealant to the wires.
Heat the free end and crush it in a vise to seal it