Tig welder question

[MSM]

Just got a used Miller 350 lx tig machine. Got it wired in,new bottle of pure argon set at 20cfh,when trying it out on steel,dc- it instantly melts the tungsten. Doesn't matter which settings used,changing the amperage etc doesn't help. I've been through all the troubleshooting in the manual but it does the same thing. Any suggestions? Thanks

 

[Welding man]

Are you sure you have it on straight polarity?Sounds to me like its on reverse polarity.What color and size tungsten are you using. You may have too much amperage for the size tungsten

 

[Bspauld]

Some Tigs have to be hooked up to a water source for cooling the tips

 

[MSM]

I've tried straight,reverse,and ac,last attempt was at 35A straight with an 1/8" orange and it instantly melted it.It's got a water cooled gun,and good gas flow through the cup.

 

[angryfatherofahemproject]

(quoted from post at 09:45:04 10/27/09) I've tried straight,reverse,and ac,last attempt was at 35A straight with an 1/8" orange and it instantly melted it.It's got a water cooled gun,and good gas flow through the cup.

35A straight is correct. 1/8" tungsten is fine. Orange tugsten is for aluminum. That would cause your problem. Get red or 2%. That should do it.

 

[Bill in IL]

Have to have DC electrode negative for Tig. For your situation I would swap leads and see what happens maybe something was changed internally sometime. Cause when you get it wrong its an instant tip burn off.

You do have argon flowing from the tip before striking your arc correct? Makes a mess when not enough gas flow and burns the tip. I usually run 1/8 inch tungsten I have run up to 100 amps with no problems.

 

[Puddles]

I use 2% Ceriated (Orange) tungsten on my inverter Tig machine all the time for mild steel welding. I use 2% Lanthanated (Blue) for all my AC aluminum welding.
I went to Miller’s site and looked up the Syncrowave 350 LX, right on the front page Miller offers 2 % Cerium (Gray) in their torch accessory kit. Cerium is the European and Asian version of our Ceriated.
If by chance as already mentioned the leads are not crossed inside the machine, and you have proper gas flow, I think you have a serious problem with this machine! :shock:

 

[T_Bone]

Hi MSM,

When having welding problems of this type, I find it best too take another look at all machine connections.

I too would suspect that your using the wrong polarity.

Take five, and reread your manual and double check your set-up connections and settings.

Pay real close attention to the grounding requirements of the surrounding area. HF will cause some weird things too happen at times.

T_Bone

 

[Anonymous-0]

If you've tried all polarity's and it still melted, I'd make sure the gas was flowing out the nozzle. On the higher end TIG machines, the gas flow is operated by a solonoid that's usually activated with the foot pedal. A lot of torches also have a valve on the torch that has to be open. Maybe the solonoid is bad or the hoses connected wrong or the torch cable was crushed and gas flow is severly reduced? You should be able to hear the argon flow at the nozzle. Try turning up the flow. Even a pure tungsten shouldn't melt unless the current is way too high. Striking an arc on DC+, for just a second or 2, on a piece of copper, can clean a slightly contaminated tungsten. Make sure the water is flowing too but that shouldn't cause the tungsten to instanly melt. Are you positive it is a tungsten? How does the machine weld using stick? That could tell you if it's a machine problem. Sounds like a gas flow problem to me. Maybe the polarity switch is faulty? Dave

 

[Anonymous-0]

I just thought of something else. Make sure the cables aren't wrapped on the machine. I worked at a place that had a synchrowave 250 that the meters didn't work. A previous welder made a cable rack and it was mounted on the machine cart. The high frequency went through the cables into the cable rack and fried the meters. Possibly something similar could have wrecked something on your machine? The cables shouldn't be hung together on a TIG machine and it's best to have them hung up away from the machine. Dave

 

[guido]

Hello MSM,
Turn the welder on and check the open voltage at the leads.It will tell you which of the lead is + and which is -.
Like yhe other post suggested, it sounds like the wrong polarity.
Guido.