Mig welding shield gas question

I just bought an ESAB MIG welder from a friend of mine who was using it for Aluminum. It's the first MIG I have owned and I have a question about the shielding gas I should use. The machine was sold to me with a bottle of pure Argon. I'm going to be welding mostly mild steel, and read somewhere that for arc stability on thinner materials I should be using an Ar, CO2 mix. The other day I was trying to weld 2 pieces of

16ga sheet steel with .035 wire and couldn't keep the weld from blowing through the metal. No matter how I adjusted the machine I couldn't get it right. I assume that it is partly my newness with this machine. I was having trouble maintaining an arc at amperages low enough to keep from blowing through. When the settings were low enough to keep the metal from holeing I got almost no penetration, and very tall (rabbit turds) beads. Would switching to a CO2, Ar mix help? I get great welds on ¼" with this current setup.

Thanks

Peter-

Reply to
Constant Velocity
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Argon for aluminum.

Argon/CO2 for steel.

Check your polarity if it is adjustable.

Refer to the manual, or sometimes there is a guide on the inside cover. Maybe be able to find one online.

Welding 16ga. with .035 is a little too much. Either try smaller wire, or just spot weld it. Pull the trigger for a very short time and get one spot. Then do it again. DO NOT make the spots all in a row, or it will distort quite a bit. Space them out and jump back and forth and allow time for cooling inbetween. Keep the distance the wire sticks out at the diameter of the cup or less. Angle the torch from 90 degrees to about 75. Position the torch so that you can see the puddle. With spots, you probably won't see much. An autodark hood helps. When spotting, lots of times, I just get into position, look away, close my eyes, and spot.

You will not be able to "maintain an arc" for very long on sheet metal because you will reach the melting point, and it will fall away. Any metal will do this when the size of the puddle is too large for the cross section of the molten pool in comparison with the thickness of the metal.

Keep trying. Try the things I suggested.

It can be done.

Steve

Reply to
SteveB

Definatly get a different gas. While argon will work for MIG, and is required in some applications (alum), it's not a good general purpose gas. CO2 is the cheap variety of general gas, but using 75/25 mix (argon CO2 mix) will usually produce a better looking weld (less spatter). Welding 16ga with that thick of wire will usually require pretty low settings, and you'll have to move right along to prevent turning your welding into a hole maker.

Reply to
Lynn Amick

75/25, or C25 is the mix for general purpose MIG, but if you are blowing through now with pure argon, it's not going to cure that, in fact, it will be hotter with the CO2.
Reply to
ATP

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