William Noble wrote:
"RoyJ" wrote in message
...
What Tim said. But the flux must be ACID. My local weld shop has some
proprietary formula stuff that works great but good old HCl has merit.

good catch - I didn't think of mentioning ACID flux - I've had good luck
with the paste stuff sold for soldering copper pipes - it's a little easier
to work with (well, a LOT easier to work with) than liquid HCL, and with a
wire brush (by hand) and some heat it will clean up a solder joint nicely
for resoldering.

And if you have it, use an oxy/ace torch instead
of propane. Set it for a gentle, bushy oxidizing
flame. I've successfully disassembled, rodded and
reassembled two radiators. I tried propane and I
found that the heat was too low and not nearly as
controllable as oxy/ace.