MTS250S Weld Cast Iron and Aluim.

[Kempy]

Looks great. Thanks for the demonstration. The helium seems to make all the difference. Looks like another gas I should keep around. I haven't used it since school, and then the price was a lot more reasonable.

The only thing with helium is it will leave the weld black on top but comes off easily water and a wire brush or soap and water. I will be cleaner if you us 25% helium 75% argon or 50/50 an a lot of heat and thicker metal.

[performance]

The reason the black soot is left is because the Helium is virtually leaving the weld area right after it is applied. That's the down side to helium, no one talks about. It's lighter than air, and as soon as it exits the gun, starts to float up and off. Argon is heavier than air, and stays where it is put when it is done down hand. The black is oxidation actually.

[zoama]

Zoama585
You got the 250P how do find the pulse work on it? I is you don't have a spool gun but with it I find it so handy with the 25 ft. line the only thing you have to watch out for is tipping the gun to sharp and the gas line will kink a little and slow the flow down if you put it over your shoulder it works fine.

I've only used pulse to weld a flowmaster muffler back together after I opened one side with the plasma cutter. I have no formal training in welding and I don't fully understand how to use the pulse feature... but I will learn.

[Kempy]

The reason the black soot is left is because the Helium is virtually leaving the weld area right after it is applied. That's the down side to helium, no one talks about. It's lighter than air, and as soon as it exits the gun, starts to float up and off. Argon is heavier than air, and stays where it is put when it is done down hand. The black is oxidation actually.

I modified a nozzle to get the flow on the weld better, it did help the black. I made no changes to the settings just the nozzle would have to do more test to get the weld better. Maybe I will try welding upside down and let the helium work the way it wants.
The argon does make a nice weld and cleaner. It only took a few swipes with a wire brush and it was clean.