I got some of the metal waterproof switches and the tails here: http://adafruit.com/products/1152
I'm planning on using these in a car and I'm concerned about vibration and environment. The crimped connectors on the tails have a little bit of grab but not a lot. I think it's likely they'd work loose over time.
I did a test, driving an automotive relay (87a) using some Cat5 wire and it seemed to work fine. What I did was take a pair and twist it together on each end to give it a little more copper. I had this hooked through the hole in the switch referenced above. I know I can run some solder on there and then some heatshrink and it'll probably be ok.
My concern is the Cat5 solid wire is a little brittle in short streches like that. I'm concerned it's going to snap off over time due to the environment and vibration.
Anyone have a recommendation for a better way to wire this?