I've had good results joining aluminum tubing used for antenna sections. I
dunno about the reliability of using it on A/C system parts, but I'd expect
the results to be good.
This product isn't quite the same as a solder, in that I don't think it will
creep into a joint, in the way that soft solder does on a fluxed copper
fittings joint.
This stuff is scratched into the joint or repair area to keep the surface
oxides broken up. It doesn't actually tin the parts in the way that rosin
core solder does on clean copper.

The different brands of the rod I've used, including the one you saw at the
tractor/ag store, have all appeared to be the same product.
The application is more like brazing or welding, rather than soldering.

WB
.............

"George" wrote in message
...
If it works on spark plug holes, that could be real nice. Have you
ever tried it on anything like a worn car AC condensor?

Other folks have said the rods are Zinc. I've read that Zinc is
popular for what they call "Lost Wax Zinc Casting".
http://www.popsci.com/popsci/science...470950,00.html
http://www.ray-vin.com/casting/lostwax/lostwax1.shtml