Run into problems after changing gas

[Escy]

Hi guys, new here. Looking for a bit of advice. I'm new to welding. I'm working on a car, welding thin steel with 0.6mm wire. I bought my welder second hand and it came with a big bottle of gas which I was told was argon. (don't know if it was pure or a mix). I've been welding fine with it, getting pretty decent. The gas ran out so I bought a bottle. After speaking to the person selling the gas I was advised to get argon mix for thin metal which I did. I'm convinced this is different to whatever I was using before.

Now when i'm welding i'm really struggling. The piece of metal i'm welding in isn't a perfect fit, there are a few gaps, this usually isn't an issue for me, I could gradually build the weld up. (it's a bit of body work, not structural)

What's happening now is the gas almost looks like it's coming out of the torch as a blue flame, the wire doesn't really seem like it's hitting the metal (i'm welding vertically), it's almost like it's melting too quick and blobbing up.

Before, i'd get a crackle when I was getting nice penetration, now it's not sounding the same, more of a humming.

My welder is on it's lowest setting, i've tried adjusting the pressure of the gas up and down, i'd tried changing the wire speed.

I'm hoping someone can offer some advice as i'm making a mess at the moment and getting frustrated.

 

[dan.taylor.1]

Does it not say on the bottles what's in them?

Have you changed or knocked the flow knob, or can you check what pressure your output is from the regulator on the gauge?

Dan

 

[Jan]

I've had similar experiences on the odd occasion. I can't say exactly why it's happening, but I can say what is happening. The molecular physics are far too complex to go into here, but in practice you are forming an electrical arc between the torch and the work piece. As the argon enters this arc it will be 'excited' into flourescing much as it does inside an argon light tube. All the Noble Gasses will do this and each has its own characteristic colour from Helium (red) and Argon (violet) through to Radon (green). Surprisingly I've noted that when welding flat and the right way up a weld puddle will still form and the two pieces will have stuck together. Though how well I couldn't say.

 

[Escy]

The bottle i'm using now is 5% Argon mix. The old one didn't say anything. I've been welding a bit more, sometimes everything is perfect, sometimes it's not. One thing i've noticed is that the wire seems to be melting too far away from the metal. As i'm welding vertically it's feeding through and dropping down, not always going where I want. It's almost like the settings are too high on the welder but it's on it's minimum. I tried turning up the wire speed but it didn't make much difference.

One thing I have been doing which has improved things is holding the torch further away from the metal i'm welding. I'm getting by at the moment but it's not ideal.

Dan, i've tried a few different pressures, I think it's about 1.5bar at the moment.

 

[Jan]

I'd be more concerned with the flow rate (if your meter shows this) than the pressure at the gauge. If there are any kinks or other obstructions to the gas flow the pressure showing isn't worth a damn.

 

[Escy]

It doesn't say the flow rate. Nothing has changed with that side of the set-up, I just swapped from one bottle to another. There is plenty of gas coming through. Can too much be an issue (other than wasting it)?

 

[Jan]

It's been said that a (seriously?) too high pressure/flow rate from the nozzle can upset the weld puddle. I can just about envisage this getting to the point where it blows away a lot of the heat from the surface of the puddle. Are you sure that the gas valve on the bottle is fully open? Any kinks in the lead to the torch? What's the make & model of your welder? Any or all of these could be affecting your ability weld nicely.

 

[Escy]

It's a Clarke 135TE. What's seems to happen is that there seens to be a blob that grows on the end of the wire and that seems to start coming back towards the torch, as the wire feeds, it's melting before it's getting to the metal and travelling back towards the torch. I don't know if that makes sense? Due to this I only seem to be able to weld by doing little bits at a time.

The bottle is fully open and no kinks in the line.

 

[chunkolini]

Have you tweaked the wire speed by accident? try turning that up a smidge.

 

[Escy]

I've tried different wire speeds, they make no difference. Things have taken a turn for the worse, i'm really struggling now. Can't even get a decent bead down on a bench, let alone upside down on a car.

It's still doing what i've said before, the wire hits the metal, the weld starts and then the point the wire is melting at seems to travel up the wire towards the torch (this leaves me with blobs). This seems to be happening like a pulse, it travels up the wire, probably getting too far away from the metal to arc and then starts again and travels back up. Wire speed makes no difference, even on top whack. I end up with huge blobs on the end of the wire.

This whole thing might have nothing to do with the gas and maybe it's just a coincidence? Or maybe my wire doesn't like the new gas?

 

[BrokenBiker]

i may not be of any help, but take the torch apart and check the main connection that takes the current to the tip.

had a similar issue with my mates gasless and this was the fault. Tightened it up and all was fine

 

[Jan]

Although most people seem to think that the contact between the wire and the power supply exists at the tip, most welders make that contact inside the box. The Clarke may be different, but I doubt it. As such I would still suspect a poor wire feed and/or electrical contact with the wire where I'm implying - inside the box.
Since changing the liner from PTFE to steel on my old SIP (virtually identical wattage) box's torch I've seen a lot less (if any) of the symptoms you are describing.
Try 'breaking' all the push fit connectors inside the box, giving them a slight coating of petroleum jelly and then remaking them. This will remove a lot of corrosion giving a much easier path for the current.

 

[Fastfingaz]

isn't the mixture suposed to be 75/25????

 

[Robotstar5]

Although most people seem to think that the contact between the wire and the power supply exists at the tip, most welders make that contact inside the box.

Sorry, have to disagree, the reason it's called a contact tip is because that's where the welding current is transferred to the wire, all the welders I've worked on are wired like that.

 

[backpurge]

isn't the mixture suposed to be 75/25????

Not for thin metal, 25%CO2 would make the weldpool far too hot, ideal mix for sheet metal work is 5% CO2, 2% O2 and balance Argon

 

[backpurge]

Unless you have ended up with some really weird and wonderful gas mixture a change in gas isn't going to cause such a dramatic change in welding conditions, try welding with the gas turned off, the weld you get will unsuitable but if you are still getting the problems with the wire burning back you know it is nothing to do with the gas.

As has been said it sounds more like a parameter/electrical problem

Robostar is dead right, the electrical contact to the wire comes from the contact tip, the clue is in the name, it may be worth trying a new tip, if this has become damaged it could be slowing the wire feed down

 

[Jan]

If the contact is made at the tip why do most machine manufacturers claim that the torch is not live? Of course the tip will become live as soon as the wire does as they'll be in direct contact. Surely the tip is just there to guide the wire precisely where you want, which is why it has to be the same size as the wire running through it.

 

[gordon stephenson]

Torches are called not live, Because they are only live when the trigger is pressed.

 

[Wendelspanswick]

If the contact is made at the tip why do most machine manufacturers claim that the torch is not live? Of course the tip will become live as soon as the wire does as they'll be in direct contact. Surely the tip is just there to guide the wire precisely where you want, which is why it has to be the same size as the wire running through it.

Originally the torches were permanently live, pulling the trigger started the gas and wire feed, now torches are called non-live because pulling the trigger activates a contactor/relay to provide power to the torch.

 

[waddycall]

Sounds like a wire feed issue, tip, liner etc. If the wire was feeding fast enough it wouldn't ball up. Try pressing the button and aiming the torch away from anything connected to the earth return and measure how much wire comes out on a minute. You should do this when your having problems rather than when the torch is cold as tips can get worse as they heat up.