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Thread: 255EXT ac arc sputter

  1. Default

    Yes, that's a little strange. I don't know if this helps, but on my 255 I also had arc fluttering on low amps. I found out if the tungsten is too big and if the amps are set too high it will cause this. For instance if the machine is set at 200 amps and the pedal is pressed 1/4 of the way down you would have about 50 amps, if it was set at 50 amps, 1/4 would be about 12 amps. This has a big affect on small movements. It's better to set around 25amps then floor the pedal and then back off when the arc is established. I am able to weld on the bottom of soda cans, but cannot even begin to weld two together. As you said, the arc jumps from side to side then it just blows a hugh hole in the can. I figured it's just my lack of experience, maybe some day. The machines are really really good, just not great. I hope you get your issues resolved.

  2. #22
    Join Date
    Jul 2015
    san leandro CA


    Yea thanks for the input, hope so i like the machine and the price but the arc on AC just seems not to be inconsistent. DC the arc is very good on low and high amps but it does have some no starts also. If i weld at 160 amps 1/8" aluminum and it get going it seems to weld good but low amps it seems to have a problem and using the SSC pedal thought would help so i don't know i'm no expert welder ether i'm going to have a friend try it that's all he does is tig weld he builds pro mod race cars, headers, roll cages he has welded all kinds of trick stuff for a living for 30 yrs and tig welds everything maybe he can shed some light on it if its me or the machine , but i think the arc should be consistent when you let off the pedal and not kinda cut out and flutter.

  3. #23


    Yes, labmaster, too large of tungsten it will cause an issue at low amp. For best and most stable amp starts, 1/16 or .040" is recommended. Pedal resolution as you say also affects it.

    When an arc jumps from side to side, it is not the machine. Rather, it is the arc itself looking for a stable path to the work clamp. This can be caused by a slight, (very slight) draft that blows the low amp arc, magnetism, poor gas flow pattern, or too long of a stick out, or too much of an arc gap which makes it more difficult for the arc to find a stable, close route back to the work clamp. A wandering arc, when it wanders does increase the voltage as the arc grows. Welding is about amps AND voltage (VxA=Watts). If the voltage shoots up because the arc suddenly grows, even if the amps are stable, you've increased the wattage of the arc and will result in a hotter feel and burn through.

    No machine can make you an expert or an accomplished welder. As far as the machines being, very very, good, I beg to differ. The machines are great overall. They weld as well as any on the market as far as that goes. Time and again, I get letters from seasoned pros telling me just how good they are. I know myself as I've welded with almost all of them at one time or the other. I find that people that tend to pick apart the machines for this or that aren't really well acquainted with the full spectrum of welders on the market. Now, that does not mean an individual machine may be out of adjustment or having an issue, but typically, people blame the machine before they look elsewhere for the cause of the problem.

  4. #24


    Quote Originally Posted by rick9345 View Post
    Some times my skill level isn't as good as the machine.
    AS MARK said. " but typically, people blame the machine before they look elsewhere for the cause of the problem"

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