Tungsten balling on dc/ms

[HMB]

Is this normal?

 

[BrokenBiker]

what tungsten and amps are you using?

 

[biffa]

Pictures would help a lot, is it balling up straight away, or after a while? Are you sure your not dipping the tungsten in to pool or the rod onto the tungsten?

 

[hotrodder]

As said, a pic*/more detailed info would help but to get the obvious one out of the way check the polarity; torch wants to be negative (DCEN). DCEP melts the tungsten as around 2/3 of the arcs heat occurs at the positive electrode

* a pic would make it very easy to differentiate between the tungsten melting due to wrong polarity (clean & shiney), one that's burning up due to a gas leak drawing in air (blackened charred mess), one that's overloaded amperage wise on DCEN, one that's contaminated with a blob of steel etc

 

[HMB]

I'll get some photos

 

[HMB]

As said, a pic*/more detailed info would help but to get the obvious one out of the way check the polarity; torch wants to be negative (DCEN). DCEP melts the tungsten as around 2/3 of the arcs heat occurs at the positive electrode

Just looked at front of welder and the idiot proof pictures say torch +ve return -ve

 

[BrokenBiker]

try swapping them around and see what happens. I run mine torch negative and it runs fine. Never tried it torch positive though

 

[Paul.]

Just looked at front of welder and the idiot proof pictures say torch +ve return -ve

DC Tig needs to be torch negative, as Hotrodder has said 2/3rds of the heat is produced at the positive electrode and will cook the tungsten within seconds if connected backwards.

 

[justmental]

Just looked at front of welder and the idiot proof pictures say torch +ve return -ve

for stick welding yes but for tig torch is -ve

 

[hotrodder]

Just looked at front of welder and the idiot proof pictures say torch +ve return -ve

From your previous posts (be a LOT easier if you included relevant info when asking for help) it's a Thermal Arc 250 AC/DC? What is the EXACT model as they had several 250A TIGs, some of them have multiple sockets on the front and others have a polarity switch* instead. Swapping the leads around if it has a polarity switch ain't the best way to fix things but the short version is that it's either labelled wrong, connected up wrong or there's a switch in the wrong position as (with a couple of specialised exceptions) the torch NEEDS to be negative for DC TIG. As an aside incorrect polarity will also mess with the way AC balance settings work when welding on AC


* for example...

lever on the right hand side selects AC, DCEN or (how it's set in the pic) DCEP

 

[HMB]

About best as I can get till later. It's been ok with ac Ali so far ??!!

 

[HMB]

Well I swapped them over and it didn't like it

 

[BrokenBiker]

when you say it didn't like it what do you mean? did the tungsten melt? ball up even worse? spit and stutter, unstable arc etc? is it shiny or a horrible grey burnt colour now that you have swapped them?

 

[overload]

HMB, your machine takes the torch on - (F3) and the earth on + (F34).

Once tig mode is selected (F14), (F24) lights up. Select the correct current by pressing (F15). You have AC if the light is on, DC if not ( F26).

That's how I understand it anyway!

 

[HMB]

That's how I understand it too.

Wheni swapped connections over, tungsten had hissy fit and dissolved

 

[overload]

The connections stay in the same place whether you welding Tig AC or DC. You only change the current on the panel as I've described.

When you're trying to weld stainless or mild, is the panel light (F26) off?

 

[HMB]

Yep f26 is off. Still balls up. Was using 50/50 Ar/He not that I would have thought it'd make any difference

 

[overload]

Sounds like a faulty machine. I was going to mention if it sounds different when choosing between AC and DC because obviously AC produces a louder buzzy sound whereas DC is nice and quiet when welding.

If it makes the same sound when the machine is saying it is in either AC or DC, then it's definitely got a fault.

 

[justmental]

can you make a short video of the welding and showing it balling up at the end