OMRON Switch, Soldering Guidelines:
Temperature must be as low as possible, THEREFORE, use Leaded Solder.
63% tin-37% lead, Kester 44, --recommended--
300-350F is the range of temperature you want. as per spec-sheet, complete soldering at NO MORE than 3 seconds MAX..
DO NOT operate or at all perturb the switch immediately after soldering,
The plastic is melted/soft and any movement will cause internals to mis-align
Make sure to TIE DOWN the switch to the pcb using twist ties.. tie the switch down the middle, Solder the two outside joints, then remove the twist tie, and solder the middle. Wait for complete cooling before removing the twist tie to solder the middle pin..
To prevent overheating, you could wait for complete cooling before Each joint.
OR alternatively, you can solder all the switches simultaneously, alternating between each pin of each switch.. This gives it some time to cool..
Again, NOT jostling/engaging/pushing the switch after soldering is very important.
DO NOT RUSH, I know you might be very anxious to try out them new omrons, but if you rush, you greatly increase the odds of overheating or disturbing the switch while soft..
Take your time, these things arn't exactly cheap, $1.5 per switch, $5 shipping per package..