Tungsten turning dark gray

[jtybt]

225LX set at 122 amps/foot control AC Aluminum, AC freq dial at 9 '0clock and bal about 10 'oclock.

welding in 1/2"X1 3/4" 3/8" plugs in cast aluminum exhaust manifold to seal up water passages.

The 1/16" ceriated tungsten is turning dark gray and recedes into the cup which is getting very hot.

What am I doing wrong?

[Hamstn]

What is your argon flow?

1/16 might be a bit small or at least 3/32 would be much better. Grind the tip taper 1.5 to 2 diameters of the tungsten then blunt the tip to 1/4 diameter.

Try turning up the AC freq just a bit. 120cycles/second is a starting point.

[jtybt]

100% argon at about 10 liters. I did see a black shadow outside the cleaning halo but turning more EP balled the tungsten more.

Lowered freq(it was set about 220 hz) and didn't get as much darkening of the tungsten but the ball did explode on me. I'll have to go to the welding supply tomorrow for 3/32 tungsten.

I did get a crater that I couldn't fill, either. Drilled it out some with 3/32" bit but it wouldn't get heat in the hole. I'll try a carbide burr and 'V' it out.

[performance]

You may have a restriction somewhere, as it seems to be an issue with coverage, or it may be a contaminated tank, which is quite common these days.

Another issue might be too much torch angle. This can cause poor coverage.

[jtybt]

Got the 3/32" thoriated tungsten and put a #8 cup. I didn't get the groove filled but the 3/32 covered more area so it capped. I ground ity down without hitting a void so I plan to leave it like that. There's a 3/8"" SS flange that covers the water passages so even a small hole won't let any water into the exhaust manifolds or engine. 9 more holes to plug and I hope I'm good to go.

One thing...I don't seem to have a handle on the pulse thingy. Adjusting frequency is very obvious. How do I go about setting pulse so I see what difference it makes so I know how to make adjustments?

[performance]

Charlie,

As far as the pulse goes, I am not quite sure what you are asking, but there is no ONE adjustment that will make a difference for you. Pulse is geared toward the law of averages, all average together to form an average amperage over a given period of time. Pulse frequency is the most visible control, as you can see the pulse at slow speeds. If you can't get hold of the pulse settings, don't worry about it. It will come with time and practice. But it is not necessary for normal welding.

A #8 cup is quite large for a 3/32 tungsten. A number 6 might give you less turbulence and pinpoint coverage as far as gas goes.

[Str8sixfan]

I was recently fighting similar things on my machine. Thanks to this forum you really helped me narrow it down to a gas delivery issue. Thought maybe I had contaminated gas, or a hole in my line...turns out it was a super simple fix, that I wished didn't take me 4 days to figure out! Don't be like me! https://youtu.be/DqR_N_5xm68