"Constant Velocity" wrote in message
...
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-


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