Welding Tips and Tricks

If you have an AC only machine or an AC DC machine can you scratch start tig on AC and weld aluminum?

Hey mate,

I believe that would be a no. Ac tig works because the arc is stabilised by the high freq current super imposed over the welding current. where as the ac stick welding current is stabilised by the compositions of the electrode coating.

You can, however use an AC Tig to stick weld, with an electrode in the tig torch. HF start makes it great for tight spaces .

Mick

Zach,
As Mick has said, short answer would be no. But I have heard that on an inverter welder that the HF is only used to start the arc then shuts off even when welding in AC mode. I'm no expert on inverters but I did hear this mentioned on a video about a Dynasty 350 that was put out on youtube by Miller.

Len

A normal homeowner size machine, no.

But some people can do it with industrial machines. Like the round top lincoln Idealarc 250.

I've never tried, but some did it before realizing it was no fun and bought a tig.

I often have to scratch start the Dynasty at our shop between starts unless I want to wait for the machine to count back down to zero, which is an absolute pain with a postflow set to anything over 5 seconds. Otherwise, it just sits there beep beeping. It will restart as long as the tungsten is still glowing, but beyond that. . .you're going to have to wait. Perhaps it doesn't do this with other tungstens than pure, but it's been awhile since I have used anything else. I barely scratch it though. . .not enough to get visible smoke in the weld zone.

Now that's strange - most machines I tried will re-strike despite being in post flow - it's not just a setting thing ? some machines have option for constant HF or start only - come to think of it some plasmas do as well.

Back to original question - conventional AC welders won't successfully TIG weld - but many years ago I had a stand alone HF unit that acted as an arc stabilizer & HF supply that you could plug into any power source - I only used it DC on an engine drive - but I believe it was meant to do AC as well - looked like 60's technology & bled over a wide radio spectrum ! - I think though they continue to make a similar device - probably not worth the cost with the price of modern inverters .

Anyone tried the 'Arc Pig" ?
http://www.arcpig.com/

It may be a settings thing, but what I understood from the rep, this Dynasty, that is now about 6 years old, only had HF at start. When it beeps, you can see a spark arcing from the tungsten to the workpiece in unison with the beeps, but it will not start unless you keep hitting the switch and even then, it's iffy unless you are barely touching the base metal.

Admittedly, I never had patience with the machine because it was essentially dropped off in our lap by the rep without much in the way of a demo. We didn't choose the machine, it's what he said we needed. I didn't have time to sit down and learn a new machine, especially since what I was using was welding without issue. Few months later, I was reading a Miller brochure, that stated that the Dynasty was not an ideal machine for anodized and that the syncrowave a better choice. I wanted to know specifically what groundbreaking benefit the Dynasty offered for the material I was welding to justify the hefty price tag other than saving electricity or portability. Now, if it could duplicate a smooth (tech bypass mode) wave with full time HF like the old aircrafters and such, I would have been allover it.

I know I sound stubborn, but outside of exotic alloys, that most of us will never see, we were already getting textbook welds for years on a variety of materials. And the people who were complaining of the old tech, did not have consistent improvement with the new. In other words, their welds were still iffy, not to mention all the time that was now being lost playing with all of the settings, which led me to believe that maybe these options were more suited towards automated processes, perhaps. So now we have machines that scream annoyingly on AC, and the welds are not greatly improved, or making up for any lack of schooling or skill.

All through school, all through the years in my particular industry, everything boiled down to user skill or error, outside of perhaps, supplier goofs with gas and such. And that is still the case.

@TamJeff

Not so long back welding reps knew enough of the trade to set you up with a suitable machine ( within budgetry constraints ) could demonstrate it & do a decent weld themselves - if you were'nt getting along with it they'd come round & sort out what was wrong - all to often now their motivated only by the maximum % commission & know very little about the "wonder" tool their telling you to buy - old fashioned service is hard to come by.

Funny thing is ask most people what their dream welder is if they could afford it & most will say the Dynasty unless their dyed in the wool "red" fans - I'm slightly surprised by your opinion - but then how many people do much anodized ? - it's clearly a specialized skill that you are the master of & I imagine you can make great looking welds with nearly any machine - where no machine can make up for a lack of skill. - I welded with a few old machines & the HF was on all the time - some of them made small lightning storms ! & if the torch was'nt close enough to the work it would arc out through the hose or up your arm - made life " interesting " ! - on occasion they would suffer erratic starts caused by the points air gap inside - is it possible the dynasty still uses this & it needs looking at ? possibly the newer models don't have this anymore ? certainly some of the current import sets still have an air gap - could be worth a quick look.

I just got my snap-on inverter tig 150 up and going and I CAN scratch start on ac aluminum. the problem in have is that's the only way I can establish an arc on ac or dc.the machine has an high freq. or lift arc capability but for some reason the high freq. start is not working. if anyone can give me some advice on this problem I would sure appreciate it. is it possible that the wiring in my building has anything to do with it. not having much success so for on my tig welding , never did it before so for now im just winging it . I can lay a pretty nice bead on flat metal on any angle but when I put another piece of metal to join like a t joint cant get the puddle to get down in the root of the joint. I guess it will take some time to get it.

Sorry to hear you got problems

supply in building is not likely to cause problems with modern inverters - they usually correct for voltage variation to a degree - if outside of set parameters they usually stop welding completely & display an error code cancelled by switching off & back on - if supply voltage from your building was at fault I would expect it to show up either when first switching on or if set at maximum amps - never known one to effect the HF - so either there is some odd sequence of pressing buttons you have'nt done to select it - though from what I can make out in the picture it would appear straight forward or possible the machine is faulty - if so it's a phone call to the supplier.

With the T joint - my advice would be wait till you get the machine sorted out - then practice bead on plate till confident - then do a few lap joints - then butts & finally once everything else is second nature do the T - I mean no disrespect - but Tig is not as easy as Jody makes it look - coordinating both hands takes a while when your new to Tig - don't try rushing it - the lack of root fusion on the T joint is often a combination of small things - too big a filler rod / adding too much filler at a time / puddle not hot enough to accept filler - a little torch angle as it's harder to maintain this & see the puddle compared with other joints - a slightly long arc length for the same reason & you will likely need the tungsten stick out longer - the taper on the tungsten & grind quality will effect how focused the arc is into the T - & for the same thickness material this joint requires more amps - so you may just be a little cold - all of those can cause your problem - & if it's aluminum be aware that even maxed out your machine is not going to weld much thickness without helium mix & / or pre-heat - I'm sure in time this stuff will just click & you'll wonder why your first attempts frustrated you so much - obviously watching the Guru's video's will help - but if you know anyone with Tig experience invite them round - promise beer / pizza whatever it takes & either watch them weld or have them critique you - I've helped a few people locally this way - it often only takes a couple of minutes to identify the problem & get them going - sometimes it's as simple as grinding the tungsten.

Good luck

noddybrian wrote:@TamJeff

Not so long back welding reps knew enough of the trade to set you up with a suitable machine ( within budgetry constraints ) could demonstrate it & do a decent weld themselves - if you were'nt getting along with it they'd come round & sort out what was wrong - all to often now their motivated only by the maximum % commission & know very little about the "wonder" tool their telling you to buy - old fashioned service is hard to come by.

Funny thing is ask most people what their dream welder is if they could afford it & most will say the Dynasty unless their dyed in the wool "red" fans - I'm slightly surprised by your opinion - but then how many people do much anodized ? - it's clearly a specialized skill that you are the master of & I imagine you can make great looking welds with nearly any machine - where no machine can make up for a lack of skill. - I welded with a few old machines & the HF was on all the time - some of them made small lightning storms ! & if the torch was'nt close enough to the work it would arc out through the hose or up your arm - made life " interesting " ! - on occasion they would suffer erratic starts caused by the points air gap inside - is it possible the dynasty still uses this & it needs looking at ? possibly the newer models don't have this anymore ? certainly some of the current import sets still have an air gap - could be worth a quick look.

It's mostly user error on my part. I don't want to (I refuse) grind tungsten so I use pure. I have the machine set to values similar to standard square wave so that's likely the issue.

Much of what is setting people's desires for inverters is lack of electrical service capabilities, and internet hype and the thought of putting the time in to become an ace. When I bought my old transformer, I knew I was going to need to upgrade my service. I also wanted the service upgraded for other heavier types of equipment and I wanted a seperate panel and such for that anyway. I always liked industrial grade standards in that regard. Funny thing is, my transformer machine does not arc wander, like many people claim. It's the square wave, and the inverter machines that introduced me to that phenomenon. Sure, it can be adjusted out with all of the settings but I'm over that. I was getting text book welds for years with the old tech on a variety of materials and all based on knowing the basics and a lot of to do with technique. Finally, that obnoxious screaming sound of the square wave/inverters when welding AC. To me, that just seems a bit too dramatic to end up at essentially the same result.