Brent Philion wrote:

David Billington wrote:


You can weld Al with DC but use the reverse polarity to what you would
use for steel. I have never tried it. It does result in much more heat
at the torch so you would need to make sure the torch was up to it. I
think this would be like running AC TIG with the cleaning setting maxed
out.


Tried it using both polarities and scrubbing like no tomorrow

DCEN
It hold an arc but staunchly refuses to flow liberal application of
filler can bind them but there is no strength (Logical reason being the
aluminum is encased in aluminum oxide which is forming a solid shell
DCEP
Black coating forms on the base metal arc wont strike

Run a helium mix with a small amount of argon to ease arc starting. You
can also try scratch starting it (with hf on though) Once you see the
skin just pop the skin with the filler.

Sounds like your filler needs to be cleaned too based on the DCEN
problems.