Prepare LED module

Step 3: Prepare LED module

This step involves mounting the LED module and power wires to the thermal substrate. There is a correct way to perform reflow soldering... and I am pretty sure the following is NOT it. Therefore, I highly recommend doing alternate research as these components are the most fragile and most expensive parts of the flashlight. The following does seem to work for me, so if you are feeling brave, proceed at your own risk... You could also probably buy pre-mounted LEDs... but that may require modifying the Lens Bushing/LED Cap..

Tools/Materials Needed:

Soldering iron
Wire Strippers
Flux cored solder
Soldering paste
Small frying pan/skillet
Tweezers
Cree Xlamp XM-L LED (Mouser PN: 941-XMLAWT0000LT50E3)
LED thermal substrate (Mouser PN: 951-804936)
14" of black 20ga stranded copper wire
8" of red 20ga stranded copper wire
3 - D-cell batteries

Step 1: Strip/tin 1/4" of one end of each wire

Step 2: Apply solder to one of the positive and one of the negative pads on the thermal substrate. Keep in mind that this is a heat sink, so it takes a long time heat up. Also, the solder doesn't have to be pretty, as it will remelt when doing the reflow soldering.

Step 3: Apply a small amount of solder paste to the LED pads on the thermal substrate.

Step 4: Place LED on thermal substrate. Be sure to orient the LED correctly. It is hard to see but there is a little "+" in one of the corners of the LED. Refer to Appendix A of this instructable for the LED datasheet.

Step 5: Turn on stove to medium heat and place thermal pad in frying pan/skillet. Watch closely and remove thermal pad when the solder paste melts. Depending on what types of solder/solder paste you use, you may be able to use the melting of the regular solder as an indication that the solder paste is about to melt.