ORIGINAL: Lightfoot
I always use Z-bends at the servo arm and threaded clevis at the control horn. I am good at electrical soldering but for some reason, I can't seem to get a good mechanical solder joint. I think it is probably the soldering iron I use. Regardless, I still prefer the combination that I use. To me, it is the best of all worlds.
i would bet that the soldering iron you are using is not enough power try a 60 watt or higher iron. 100 or 200 if you will be soldering landing gear. i never solder on a circuit board myself. I'm to heavy handed and slow and build up to much heat. that being said i do solder wires together fine along with solder clevis'. and have never had a problem just keep me out of receivers or anything like that.