Dynasty Owners: AC Balance Control & Pulsing Q's

Well, I am not sure if it is different for the Dynasty than other machines, but in general you will leave the AC ballance at about 30% or

You can cheat it towards "Max Cleaning" if the aluminum is especially dirty or has been sitting outside for a long time. Exposure to the elements promotes a heavy oxide layer that can be a bitch to weld through.

For example, a friend of mine brought over a window frame he desperately needed repaired so he could close the sale on his old house. It was more oxide than aluminum, but by playing the arc over it back and forth at low amperage I was able to eventually convert most of the oxide back to aluminum and weld the broken hinge point. I had the AC balance on 10% (1 out of 10).

For higher penetration and longer tungsten life you can cheat the ballance towards "Max Penetration". To do this you will need very clean aluminum, but it will make it faster to weld.

From past posts of mine:

So "if" max cleaning is on the positive side, could I extrapolate this to say that DC TIG on aluminum using electrode positive is always on "max cleaning"?

I can't weld (I'm learning, though) but I have read a few books. Research says that cleaning is better with AC than with DC. So the answer would appear to be yes, but actually it is no. ;-)

Yes.

Sorry, but you need to read more.

AC is a mix of DCEN and DCEP. When you set the AC wave ballance all the way up to Max Cleaning, you are almost getting a pure DCEP arc.

Ernie:

When would one use DC tig on aluminum (assuming you have AC as an option?)

When would one use DC tig on aluminum (assuming you have AC as an option?)

Never.

that's what I thought....I knew I bought an inverter for some reason!

You wouldn't. It is only for those of us who have DC only inverters, or who want to weld aluminum from a DC stick welder.

I may need to read more and I certainly understand that AC alternates between DCEN and DCEP, but the book that discusses DCEP is quite clear. It says that cleaning does not work with pure Argon and DCEP, and that either some helium should be used or AC should be used. Apparently, the change in polarity is necessary to break the oxide layer.

Now, maybe the book is wrong (it is an old book from the 60s). OTOH, I would imagine that the change in polarity has a mechanical effect on the oxide layer and that may help to break it. The same effect is the reason why it is advisable to move the arc around for better cleaning.

I spoke to a Miller engineer about this a few years ago.

He said that the optimal settings for a Dynasty were different than those for a conventional transformer machine like a Syncrowave. For example, he suggested using a pointed electrode and 10% AC balance when welding aluminum. 15% if the material was really dirty.

Regards T R

That makes no sense. The part of the AC arc that breaks up the oxides is the DCEP part of the arc. The DCEN part of the AC arc is what gets you the penetration.

AC just gets you the cleaning of DCEP and the penetration of DCEN with the addition of the continuous high freq to stabilize the arc and assist in the cleaning action.

And also, you should not be movingthe arc around unless you are welding slightly dirty steel or aluminum.

In general the TIG torch travels in a straight even path along the weld. No weaves, no wiggles, no swirls, just a straight even line.

Well that tallies with my own observations. I gave DCEP a try with pure argon and found that the weld pool always had oxide scum on it making it quite difficult to distinguish it from the surrounding (solid) metal.

I haven't tried with Helium though.

-- you can contact me via

Well... I read the part of the book dealing with DC tig aluminium back and I have some excuses to make. There is a paragraph in the book which indeed says "no cleaning with Argon and DC tig unless helium is used", BUT this paragraph discusses DC electrode NEGATIVE (I overlooked the indication that they were not talking about DCEP any more). So indeed I was wrong. Sorry again.