Step 3: Hack Your Cold Heat Soldering Iron (3 - Modify)
With your case modified and your components removed, it is time to make modifications and integrate the parts. First, scuff the inside wall (opening side, not hinged side) of the tin where the batteries will be installed. I chose the right side. Place the battery terminal designed for both positive and negative on this wall, heat it up, and solder the battery terminals to the wall. Since the tin is essentially a large heat sink, it will take a lot of heat to get the solder to stick to the wall as well as the terminal. Again, refer to the photos for dimensions. With this in place, cover the entire interior of the case with tape. The tin is conductive, and these batteries have a lot of energy in them. If you do not tape the walls, you could complete the circuit, drain the battery, and create a potential fire hazard. Do not be scared of this, just respect the power of the batteries and be safe.
Next remove the positive terminal (no spring) from the LED, and connect the red wire directly to the LED. At this time, you can shorten all of the cables as much as you want for packing convenience. It is not necessary, but it is recommended.
Add a short length of wire to the LED terminal with the red wire to attach to the just removed positive terminal. You will also need to solder a wire from this same junction to the center tab on the CHSI tip holder (thick yellow wire in image).
Replace the center terminal wire from the switch with a longer wire, and attach this to the negative battery terminal (with spring). Cover all exposed metal with electrical tape, tape the white LED (near the tip) to the tip so the light shines through the hole in the case for the tip, and cover the circuit board with tape. Attach the red LED to the tape covered circuit board, and stuff everything into the case as shown below. You may need to tape or epoxy the switch in place depending on how your installation worked out. It is possible to use just tape and friction from the wires, but use adhesive if you are looking for a more permanent fix.
You are now done with the Cold Heat Soldering Iron hack.