Dynasty 200DX A/C problem

[Legion]

I've got a newish Dynasty that only has a few dozen hours and a few hundred arc starts on. Serial number says it was made in 2012. I've done all DC mode with no problem but never tried it on AC. Well, this weekend I bought a piece of scrap aluminum flat bar from the local metal shop and had a go.

Brand new CK 210 torch with gas saver setup
3/32" 2% lanthanated
About 15cfm argon
about 5/32" aluminium, or maybe 3/16"
5356 filler
rmt std pedal setting
75% balance
120Hz freq
Anywhere between 100A and 150A on each attempt

Let me start by saying this machine has always made funny noises, like a leaf caught in a fan. I'm in Australia and the distributor here said that was normal, just the auto-line working with my 400V three phase supply.

Anyway straight away on the first start the HF was going crazy, crackling away to the point of scaring me. Nothing like any of the steel I'd arced up on before. No arc initiated and there was a big pop so I got scared off. I got braver and kept at it and each time was the same.

I just about had to touch the tungsten to the metal to get an arc. Once the arc was started, it stayed as long as I was within 1/32" or so, which I found very difficult to maintain.

No puddle formed. The arc blasted away the base metal. It blasted away the filler on the one or two occasions I was brave enough to put it near the arc. The aftermath looked overcooked. It reminded me very much of the time I mistook a cast aluminum piece for cast steel and tried to tack weld it with 6012 rods probably on DCEP. Same popping and blasting away and drops of molten metal flying away in liquid form.

I tried about 10 starts and each was exactly the same. Either nothing but loud HF cracking (poorly, not like the smooth steel initiation I get) or if I just about touched the metal I'd start an arc that blew away the base metal and left dirty contaminated looking aftermath.

So I'm guessing the machine is failing to produce one of the phases of the AC waveform? Is this a common problem? Easily fixed? Cruizer, you reading this?

For those that read "brand new torch" - I thought that that might be the issue so I switched to DC and ran some steel beads and they were fine.

[cope]

I recommend getting a piece of known alloy aluminum. It is possible you have a defective machine, but your aluminum is of unknown origin. Might also try 4043 filler.

[TSBWeld]

Dynasty 200DX A/C problem

Agreed, find some known base metal and change to 4043 filler. Make sure everything, base metal and filler wire is cleaned with stainless wire brush and some acetone. Try turning the machine to a 68%-70% balance for a bit more cleaning action.

Process of elimination, start by eliminating the easiest variables.

[ja baudin]

Compared to DC, AC tig is very noisy. 3/16 material, you should be in the 150-180 amp range...my opinion....125 is my initial start for 1/8 th. 62 on the ac balance is where I usually stay, I like a clean puddle. Have you tiged aluminum before? You can't sneak up on aluminum. Prop up in the joint, floor the peddle and start moving!! Over heated aluminum is grey and grainy. Stay ahead of the heat and your bead will be clean and shinny.

[Bodybagger]

My suggestion is to find someone experienced with aluminum on the Dynasty line of welders and let them have a run. They'll be able to tell you if it's operating correctly. It's a big jump to assume the waveform is screwed up based on your first trial with aluminum. If you've never TIG welded aluminum before, your prior experience means little. It's a different animal. AC TIG on an inverter is loud and obnoxious. It makes short-circuit MIG sound pleasant.

[GlenC]

Since this was a "used" machine, I would reset the machine to factory default, just in case the previous owner set something wrong...

[Legion]

I did a factory reset and then tried a few advanced menu things at weldingweb suggestion (set tungsten to GEN, kick up start amps to 200A). Didn't help so back to 094 tungsten setting.

Compared to DC, AC tig is very noisy. 3/16 material, you should be in the 150-180 amp range...my opinion....125 is my initial start for 1/8 th. 62 on the ac balance is where I usually stay, I like a clean puddle. Have you tiged aluminum before? You can't sneak up on aluminum. Prop up in the joint, floor the peddle and start moving!! Over heated aluminum is grey and grainy. Stay ahead of the heat and your bead will be clean and shinny.

At 150A it was blowing through the base metal. Like arc gouging. I was too scared to linger, but on one "weld" it got up to around 1/8" deep. On each arc it did the same, like blowing foam with an air hose.

First time aluminum. I have played with high speed DC pulse and once I did get an arc it sounded like that so I figured the frequency of "something" was correct. But to get an arc I had to get to at least 1/32" or less, way closer than I'm comfortable trying to hold an arc. Like very nearly touching.

I can switch to DC on steel and it's great and normal. Switch to AC and disaster.

I could try some different ally, but that'll have to wait until next time I visit a metal shop. Plus, I would think even on a non-weldable alloy I could hold a stable, relatively normal arc? Not even close on this.

One guy suggested to set balance to 60% without explaining, so I did without thinking. He was trying to see if it balled. I am using razor sharp tungstens and there was no balling at all.

Some pictures:

Some "welds" from above:


Profile:


Dirty old rusty steel worked fine, except one gas issue. Ran the middle steel bead then switched straight over to AC/ally and did the middle bead going right to left about an inch long. By the end it was over 1/8" deep and pushing a big mound of dirty contaminated aluminum.


Tried three different torches, a CK TL210, a CK FL150 and a generic Chinese:


I did a bunch of debugging with weldingweb help and despite being an AC/aluminum beginner, I'm confident enough in my technique and troubleshooting to think there's a problem and it's not just me.

Most of these (except the one attempt with 60% balance) were done with 75% balance, either 120Hz or 60Hz frequency and all but two with 150A. The two others were with 100A and it didn't blow through with that much heat but at 150A as I said it was like blowing foam with an air hose, and not much slower than that either. That 1" weld was about 1.5 times as fast as I'd do steel and I was still balancing the tightrope waiting for it to blow through the back of the material onto my foot.

[WillieB]

No balling at 60% EN indicates a problem. My 280DX at 60% will ball somewhat immediately. I'd be trying at 75 to 80 %, If you need more cleaning action, turn it down.

[cope]

"Plus, I would think even on a non-weldable alloy I could hold a stable, relatively normal arc?"

No, it will not hold a stable arc

[ja baudin]

I did a factory reset and then tried a few advanced menu things at weldingweb suggestion (set tungsten to GEN, kick up start amps to 200A). Didn't help so back to 094 tungsten setting.



At 150A it was blowing through the base metal. Like arc gouging. I was too scared to linger, but on one "weld" it got up to around 1/8" deep. On each arc it did the same, like blowing foam with an air hose.

First time aluminum. I have played with high speed DC pulse and once I did get an arc it sounded like that so I figured the frequency of "something" was correct. But to get an arc I had to get to at least 1/32" or less, way closer than I'm comfortable trying to hold an arc. Like very nearly touching.

I can switch to DC on steel and it's great and normal. Switch to AC and disaster.

I could try some different ally, but that'll have to wait until next time I visit a metal shop. Plus, I would think even on a non-weldable alloy I could hold a stable, relatively normal arc? Not even close on this.

One guy suggested to set balance to 60% without explaining, so I did without thinking. He was trying to see if it balled. I am using razor sharp tungstens and there was no balling at all.

Some pictures:

Some "welds" from above:
[ATTACH=CONFIG]34612[/ATTACH]

Profile:
[ATTACH=CONFIG]34613[/ATTACH]

Dirty old rusty steel worked fine, except one gas issue. Ran the middle steel bead then switched straight over to AC/ally and did the middle bead going right to left about an inch long. By the end it was over 1/8" deep and pushing a big mound of dirty contaminated aluminum.
[ATTACH=CONFIG]34614[/ATTACH]

Tried three different torches, a CK TL210, a CK FL150 and a generic Chinese:
[ATTACH=CONFIG]34615[/ATTACH]

I did a bunch of debugging with weldingweb help and despite being an AC/aluminum beginner, I'm confident enough in my technique and troubleshooting to think there's a problem and it's not just me.

Most of these (except the one attempt with 60% balance) were done with 75% balance, either 120Hz or 60Hz frequency and all but two with 150A. The two others were with 100A and it didn't blow through with that much heat but at 150A as I said it was like blowing foam with an air hose, and not much slower than that either. That 1" weld was about 1.5 times as fast as I'd do steel and I was still balancing the tightrope waiting for it to blow through the back of the material onto my foot.

Looks like your not getting gas coverage maybe or it looks similar to welding aluminum in DC.

[cruizer]

I don't generally answer posts on the weekends, especially posts without a serial#

[Bodybagger]

I thought it was pretty bold to assume that the EP portion of the waveform was dropping out. But now that I've read about the tungsten staying sharp, that's much more suspect. And if your arc voltage dropped to zero or near zero for 30% of the 120Hz, it would be dąmn hard to keep an arc alive.

Have you tried AC stick welding with a 7018AC rod? Give that a try and see if the arc is really hard to maintain.

Try AC TIG welding some steel with the EN set to 99 and back it down 5% at a time and see if the arc becomes more and more unstable. Let us know what you find.

[Legion]

Great ideas! I probably still have some 701x somewhere or otherwise I've got heaps of 6012/6013 and at least one pack I checked this morning are AC capable.

I've always wondered what happens with TIG AC steel so I'll give that a shot too.

Re gas coverage, I've ordered a torch ball gauge to confirm reading of the torch output rather than my listen-to-gas-sound/feel-with-back-of-hand test.

I don't generally answer posts on the weekends, especially posts without MC430156La serial#

MC430156L

[Legion]

Well, the plot thickens considerably. At a suggestion from millerwelds forum, I went to run stick welds on AC to see what happens.


Wanted to run DC bead first - no strike! At all. I even tried to strike on the ground clamp - nothing.


Switched to AC - nothing.


Rods were Kobe RB-26 at 2.6mm (bit bigger than 3/32") at 80A.


I got the multimeter - nothing. Cables are good, the stinger cable had never been used (I tested it for continuity - fine).


I also got odd behavior - when I first switched it on the SSC foot pedal was still plugged in. Machine was set to tig AC, so I set it to DC to run the first bead, then set PROCESS to stick, then set OUTPUT to ON. After failing to strike a DC arc, I wanted to try AC but I couldn't switch the POLARITY setting. I had to first change OUTPUT to RMT STD and then could change to AC, then POLARITY back to ON. This happened each time. If I tried to switch POLARITY while in ON mode, I would just get HELP12 (unsupported operation, I think?).


At some stage I turned off the machine thinking the pedal was affecting things and took the pedal off and tried again but that didn't help and it behaved the same.


Similar when I wanted to get into the advanced menu and see if there was anything unusual set up there - I couldn't access the advanced menu until I switched PROCESS to TIG HF and then could get into advanced, but couldn't get in at all when in stick mode.


Surely this menu behavior is completely screwed up? I reckon I should be able to switch stick polarity without having to switch other unrelated modes.




The next test was AC TIG on steel:





3/32" 2% lanthanated
Autogenous
8Lpm argon (at ball gauge on bottle)
Probably 1/8" sheet
Ran 'em one straight after another, no cooling or anything (I figured that was irrelevant to the test)


From top to bottom - forgot to check the amperage first so the first was an outlier, a bit hot:


(i) 99% balance, 150A
(ii) 90% balance, 120A
(iii) 80% balance, 120A
(iv) 70% balance, 120A
(v) 60% balance, 120A


The first was almost the same as high speed pulse DC, same sound, same starting characteristics. Progressively through to the 60%, starts got harder until the last start was similar to the aluminum that prompted this thread - erratic HF and almost having to touch the steel.


The slight orange is because it was thin-coat galvanized and I just gave it a quick flap disc so there was some zinc contamination. I'm not sure if the progressively worse undercut was from the AC balance changing or from the built-up heat or from the no filler.


Each of the four bottom welds was about 2" long. The lump below the bottom weld was from previous test weld sanded down.


I'm guessing I shouldn't be able to TIG steel in AC mode with 60% balance?


Apologies for the cross post, for those who read both forums.

[Legion]

From memory on the last weld it went out a couple of times because arc length was critical like the aluminum problem and I got too long - the wobbly bits at 1/3 and 7/8 of the way. HF kicked in and I quickly shortened the gap and restarted on the fly.