Dustin, when you solder the wire to the diode, use an alligator clip as a heat sink on the diode stem to prevent heat damage to the diode. Don't use a soldering iron that is too hot or too cold. Remember, 60/40 solder becomes a liquid at 370 degrees F. The optimum temperature for the soldering tip is 700 degrees F for what you are trying to accomplish. If the tip of the soldering device is clean as well as the parts being soldered, you should be able to make a good solder joint in about 5 seconds. Make sure you have a good mechanical connection before you start soldering, too.

When you touch the tip of the soldering iron to the parts being soldered, establish the heat bridge by touching the solder to the junction of the tip and the parts being soldered.