[B0B]

My radiator filler neck broke off with the Quail on it and landed on the road ! I removed the radiator outer shell and cap, Drained the coolant down below the upper radiator tank, , Hung a heat gun I imagine an old style heat lamp would work too my heat gun (Harbor Freight )was about 14 inches above the top of the radiator set to LOW heat aimed at the top of the upper tank hole and heated the area to around 200 to 300 degrees F this is Hot but you must stay below the soldering melting point of the nearby joints. Next I carefully removed extra solder from on top by heating the soldered areas with a small propane torch and wiping off the solder with a wadded up rag (T-Shirt ) I did this quickly so as not to melt solder joints elsewhere on the radiator it was heat-Wipe in a couple of seconds . Then the areas to be soldered were inspected and wire brushed next flux was applied in this case it was Sal Met acid base flux . Lacking the Sal met Flux I recommend plumbing paste flux like is used to solder copper pipes . Now the actual soldering was done using a soldering gun mine is a weller D550 while the heat gun was still on low setting this along with the soldering gun or large soldering iron gives great control .The solder used was 50/50 plumbers solder with out flux acid core solder should work as well . I did this a couple of years ago and looked at the joint yesterday and it looks very good and has not leaked .
B0B in Michigan