I have all wiring out of the car, since I/other owners have spliced/cut wires, and would like to solder them. Aside from connectors (screw/crimp types), what's the best technique to ensure conductivity (e.g. speaker wires cut accept multiple speakers)? I've played around with solder in the past, and maybe it's my technique, but the soldering tip never gets the soldered-to parts/wires hot enough to create that solid bond. Eric.