255EXT ac arc sputter

Hay Guys, i have a week old 255ext and when welding on ac the arc starts off hard sometimes then you let off the pedal and the arc starts to sputter and spit ,cuts off then you give it more pedal and then it comes way up with the heat way to hot and melts a hole in the aluminum". Tried it over and over same thing but 2 day ago it worked but still had HF start problem . It has very horrible arc on sine wave, square wave it don't matter . Welding 1/8" aluminum 120 HZ ac balance is 67 #5 cup and 140 amps argon 15 3/32 tungsten . then on DC some times the arc wont start but the arc seems stable on DC . I think its a bad board on the HF side. any help thanks

If new to tig and your welder spend an evening with manual again to become familiar with controls functions and sequence of settings.
Welcome good luck


check that upslope / downslope both set to 0.
And that you are in 2T mode
Then check / ohm the pot in the pedal. should be a pinout in your manual.

In my case most of my machine errors/ problems are operator induced.

i checked the pin out and from low to med i have 0.5 and from low to med with pedal pressed i have 19.99 nothing from low to med and med to high

67% AC balance is way high for normal AC aluminum welding. If you are used to another brand of machine, remember that Everlast goes by percent positive rather than percent negative, so to get 67% negative set your AC balance to 33%. Typically that is about as high as you need to go and would probably be ok at 20% with clean material. Sine wave is not the best to use for low amperage on an inverter. It will not be as stable because the HF is only for starting, and there is no option for continuous HF which is typically used to stabilize a pure sine wave. The advanced square or soft square are the ideal wave forms for these machines. Make sure start and end amps are all the way down when using a pedal. With 140 amps on the panel the pedal should be able to smoothly control that. Strike an arc then look at the display as you move the pedal to see if the amps changes smoothly without any big jumps. If it's not smooth you might have an issue in your pedal. With the machine off, work the pedal back and forth through it's full range of motion and that will often clean up the wiper on a new control.
HF on an inverter is only used for starting and is cut off once the main arc starts, so I doubt you have an HF problem, or you would not get an arc started.
You can also try using the torch switch to take the pedal out of the picture and see what happens.

whats weird it will weld fine on those settings multiple passes the next pass it can't stabilize the arc at all it shoots a big arc out then just melt the metal and wonders all over no control , have to stop and restart then it will still be all over then it will weld fine, i think it might be the pedal , sometime have a problem of the arc starting at all hit the pedal and nothing if i touch the material with the pedal pressed then starts up, what could be the problem with that happening? I can weld for long periods then stop then start again then arc fails then welds fine then again no start but doesn't always its intermittent. I really like the welder but i want to work everything out while its still new, i will check out the pedal i just have the stock pedal not the ssc one. I will change some settings give it a try i will update on the problems. Thanks for the info much appreciated

If it works correctly with the torch switch then you know the problem is in the pedal.

check for pre flow .5-1 s,check for post flow 5-10s enough to keep tungsten shiny clean for the next arc strike

eack pedal tap starts another preflow sequence

Thanks everone, for the help i think its my pedal been using torch switch like zoama said and seems to work ok. I have an ssc pedal from my lincoln 185 tig that im going to see if ssc company can send me the everlast connector for it and if it will work if not i will buy a new one.
Thanks again i will keep everyone informed

Make sure you have only "pedal" selected. Or make sure you don't have upslope/downslope set to anything but zero. Also make sure end amps are set to minimum value.

And clean. clean clean, your work clamp connection (hooking it direct to the metal you are welding as well) and double check to make the cable is tight and clean in the DINSE connector on the work clamp.

Thanks Mark for the reply, the up and down slope is 0 and end amps are as low as it goes and my clamp is tight and grounded good ran multiple passes with the torch switch and it seems like its the pedal, torch switch works good had two start fails on a/c but the arc is alot better and stable than it is with the pedal.

Still having issues on ac side this cant even hold an arc at 5 amps like on dc there is gotta be a problem with the ac side of this machine i bought an ssc pedal and still the arc is horrible shoot out like a flame thrower not always but still the arc is all over not steady like on DC

What is your arc length? Too long an arc can give you fits with low amp AC.

Its 1/8 to 3/16 it can"t start an arc on 5 amps on ac and has a hard time on most amps once it gets going it works but when you let off on the pedal the arc get all weird i tried a soda can and soon as you step on the pedal it burns right through and its on 5 amps max, dc works fine, on ac it just changes tone and jumps all over and if u let off the pedal the arc continues and dosen't shut off some times not always. just got the SSC pedal but did it with the supplied pedal i think its the machine, tried it with torch switch same thing, on high amps it has a hard time starting the arc and keeping it steady also but no always been doing it sense i got it, even tried it on the factory ac settings that come preset same thing it like it can"t get it going. its frustrating because i know its not me but don't know what it is. Thanks

Yeah, arc length is too long for that kind of low amps. 5 amps you have to be right on the metal nearly. Less than 1/16.

Some times my skill level isn't as good as the machine.

Ok i will try that Mark thanks thats pretty close, The big thing is with the arc when you step on the pedal the arc starts in general with any amp output but as you throttle down on the pedal to provide less heat the arc kinda just flutters and jumps all over and is for less heat inconsistent then if you step on the pedal it comes back to normal.IF YOU SET THE MACHINE ON THE PRESET AC MODE WHEN YOU LET OFF THE PEDAL THE ARC continues dosen't' shut off, sometimes it shuts off is that normal?

The factory presets are using the 2T with a 3 second downslope causing it to continue after the pedal is released, shown below. This doesn't explain all your issues, but may make sense for it continuing to weld.


AC Frequency : 120Hz AC Balance: 25% Preflow: .5 Post Flow: 4 Seconds Amps: 120 A (with pedal) Start amps: 50A End amps 50 A Upslope: 1 second, Downslope: 3 seconds, (2T with torch switch)

yes it does thanks labmaster02 , but it doesn't always do it. kinda weird just like the arc flutter on start up but not always