A lot of soldering irons are too low in wattage to be really good. Around electronics/electrics in our old mercedes about a 60 watts adjustable regulated iron should be about right with a pencil tip. This prevents too much heat migration as the area being soldered seems to heat up fast enough that you are not cooking components close by. You want to heat the imediate area and be done pretty quickly and that is almost impossible when wattage is too low. Also since prices have fallen a type where you set the heat range is probably available reasonably. Think ebay could be good source or electronic company going out of buisiness. Portable soldering units are nice as well but either the ni-cads weaken with age or heating effect might be too low. See them as rather short term devices. Only good really for emergency uses unless you go high end units. (My opinion only others will vary.)