I use a propane torch and regular 60-40 rosin core solder. I've bent the heck out of rods, broken clevises and threaded couplers, but never broken a solder joint. (If there's one thing I know how to do, it's stress test gear)

I use a bit of flux on the rod, slip the clevis or threaded coupler in place, and heat with the torch until the flux is boiling off, but not all gone, and not burning black. If stuff turns black, it got too hot. Then pull the torch away, touch the solder to the metal, and volia, a nice flow or solder. I can make a pile of pushrods in a hurry with this technique.