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Unstable AC Arc on low current
Posted: Mon Jan 22, 2018 1:41 pm
by Richr
New to Forums and welding..
My goal is to weld and braze auto body panels
With that said last year I got a Everlast Power TIG 200.. With the help of Jody's videos I got to the point that I can weld in DC mode on sheet metal. Did a little aluminum and it seems to be okay nothing great.. Now I'm trying to use some aluminum bronze and braze sheet metal in AC mode.. The problem I'm having is I can't maintain a good arc..
Welding at 70 amps on aluminum works, get a steady arc low current on DC works also fine..
Im using 2% Lanthanated Tungsten Electrodes, welder set at 30 amps (range is 20 to 200 amps), eliminated the foot pedal using torch switch, tried different frequency settings and balance settings and the arc is not steady, sounds like its pulsing on and off, may first guess was poor ground clamp connection. I cleaned the metal,wire brushed the ground clamp, still not good.. Seems like if the metal Im welding is better than a 1/8 inch I get a better arc, sheet metal not so good..
Now for a idea and I'm not sure what I'm talking about here.. In the manual there is a .035 inch gap they talk about. I think it's used's for when you lose your ground clamp the art goes across as .035 inch gap and I'm wondering if there could be part of the problem.. That last thought is am I trying to do something the machine can't do
Thanks in advance for any ideas
Rich
Re: Unstable AC Arc on low current
Posted: Tue Jan 23, 2018 11:34 am
by cj737
I may be a bit off topic, but why choose AC to weld sheet metal? If you want to "braze" it, use DC and Silicon Bronze. It is an excellent choice for thin body panels, and SilBr is great for ductility (flex) of the panels without cracking.
Re: Unstable AC Arc on low current
Posted: Tue Jan 23, 2018 7:51 pm
by Richr
just trying stuff... Tried silicon bronze on DC and it worked ok... Talked to the welding supply guy about aluminum bronze and would it flow better and he thought it would.. Because of the aluminum, though I should us AC... Then got off trying aluminum bronze on AC.. Now why is the arc not steady, ( I'm new to TIG welding and never any AC ) sounded like I was loosing the ground.... Think may go back to silicon bronze on DC...
Talked to the tech support at Everlast and tried some stuff and ended up with check the HF gap and adjust the gap to .030 inch... Checked the gap and it was .038, should be .035 and adjusted to .030...
Tried to get a arc using 3/32 2% Lanthanated Tungsten Electrodes, welder set at lowest setting of 20 amps and got a steady arc on aluminum... On different pieces of steel not so good... Way better on aluminum but not so good on steel....
Thats were I'm at ...
Thanks for the response.. Wait and see if anyone has ideas on what to do....
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 5:29 am
by AndersK
At that low current I would go down to 1/16 electrode. Carry current better at low settings.
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 8:34 am
by cj737
AndersK wrote:At that low current I would go down to 1/16 electrode. Carry current better at low settings.
Sorry, but this is not accurate. For some video proof, please watch this:
https://www.youtube.com/watch?v=-GJBESqEvLY
Perhaps on some older, less capable machines it was, but with any modern TIG box, the tungsten diameter doesn't effect arc stability.
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 4:44 pm
by AndersK
Based on my experience I have to disagree a bit.
It does a difference mainly at initiating the arc before it gets stable, which is most important on thin metal, not so much on thicker when you hit it harder initially.
Not all machines are equal nor the welder behind it. Aaron that shot that video is of course a lot better than me and most likely running a far better machine as well.
I couldn't read the comments , would have been interesting to see what other shad to say.
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 6:39 pm
by cj737
AndersK wrote:Based on my experience I have to disagree a bit.
It does a difference mainly at initiating the arc before it gets stable, which is most important on thin metal, not so much on thicker when you hit it harder initially.
Not all machines are equal nor the welder behind it. Aaron that shot that video is of course a lot better than me and most likely running a far better machine as well.
I couldn't read the comments , would have been interesting to see what other shad to say.
He doesn’t publish videos on YT with commentary enabled.
To your point about low amp Arc initiation/stability, this is a direct result of
taper not diameter. Kind of proves the whole point (pardon the pun).
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 6:50 pm
by ljdm1956
cj737 wrote:AndersK wrote:At that low current I would go down to 1/16 electrode. Carry current better at low settings.
Sorry, but this is not accurate. For some video proof, please watch this:
https://www.youtube.com/watch?v=-GJBESqEvLY
Perhaps on some older, less capable machines it was, but with any modern TIG box, the tungsten diameter doesn't effect arc stability.
Just watched the video, what he says makes sense as far as using 1/8, cost , time, etc, does that only apply to aluminum?
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 7:21 pm
by cj737
ljdm1956 wrote:cj737 wrote:AndersK wrote:At that low current I would go down to 1/16 electrode. Carry current better at low settings.
Sorry, but this is not accurate. For some video proof, please watch this:
https://www.youtube.com/watch?v=-GJBESqEvLY
Perhaps on some older, less capable machines it was, but with any modern TIG box, the tungsten diameter doesn't effect arc stability.
Just watched the video, what he says makes sense as far as using 1/8, cost , time, etc, does that only apply to aluminum?
No. One of his demos was razor blades
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 9:39 pm
by ljdm1956
cj737 wrote:AndersK wrote:At that low current I would go down to 1/16 electrode. Carry current better at low settings.
Sorry, but this is not accurate. For some video proof, please watch this:
https://www.youtube.com/watch?v=-GJBESqEvLY
Perhaps on some older, less capable machines it was, but with any modern TIG box, the tungsten diameter doesn't effect arc stability.
Just watched another of his videos, weld aluminum with a cheap 800.00 welder (alphatig 200). One thing I noticed, he turned the AC balance all the way up. Everybody says if you do too much cleaning action, you will overheat the tungsten. He welds until the torch is really hot, maybe thats an advantage to using an 1/8" tungsten, it can take the heat better?
Re: Unstable AC Arc on low current
Posted: Wed Jan 24, 2018 10:22 pm
by cj737
A 1/8 tungsten does take more heat than a thinner tungsten. The higher balance also increases penetration, reduces cleaning (as my machine refences balance). That guy (Aaron) is an extremely skilled welder and fabricator. He makes some great videos, provides very good recipes for his settings, and shows excellent results. A different type of video instructor to Jody, but both have provided excellent insight and help to lots of folks.
Re: Unstable AC Arc on low current
Posted: Thu Jan 25, 2018 8:19 pm
by Turbo
Lots of machines have a hard time getting a stable start in ac at low amperage. I don't know about your machine, but that is why there is a setting for tungsten diameter. The engineers have determined how high the starting amperage needs to be to get a stable arc. Bigger tungsten means higher starting amperage. I usually just increase amperage until the arc stabilizes and then back off to where I want to be at. I always use the foot pedal though.