Don Foreman writes:

If you mean joining or repairing aluminum tubing in AC systems, there
is a much better product specifically designed for that: ESAB or
Allstate #31 rod with #31 flux.

Is this what you mean?

http://www.grainger.com/Grainger/pro...mId=1611760403
http://www.grainger.com/Grainger/pro...mId=1611760431