You can't beat Harbor freight for prices but I agree with Leroy Gardner, use a micro torch. Any electric soldering iron will lose heat as soon as you touch the item you are soldering especially if it has a large amount of metal like landing gear. And butane is hotter than propane.
Cold solder joints are typically caused by heating the solder, not the item being soldered. Heat the item to red hot, then touch to solder to it and let it melt the solder.