first time welding steel with my mig machine

[dvice]

so I bought the mig to mainly weld aluminum.. and I have had it for a few years now. I finally decided to set it up to weld steel... I got the gas bottle and I bought some .030 wire. ( the machine had .023 dia wire in it, with .035 rollers!!!). I bought a few new parts as well as new .030 rollers. the project was a galvanized trailer crossmember that broke on a "T" weld on the inside of the outer frame. I went and ground away the galvanization about 1/4" around the welding edges... the machine is a Millermatic 250. I had the speed set at 25 and the power at about 22. the frame thickness is about 3/16", maybe a little more.. the crossmember is about .125 -.150 ish..... I could see the wire melting but the frame wasn't as much... so I turned the power up to 25...and still I got gobs of bubble gummy blobs that didn't seem to penetrate the frame much( a little...) no "puddle" that's for sure.

now it might have been I spilled over onto the raw galvanized area.. but then I cranked the power up to 26 or 27 ish.. and it didn't seem to make a difference... I turned the wire feed up a little... with little change...as I was getting a gob of melted wire... I didn't think I needed more wire feed!!!

there isn't much more power available.. the dial goes up to 32.....is this steel just that hard to weld? is my machine weak? gas flow was at 30psi...

lets hear some thoughts.. thanks

dvice

[fabricator]

Plenty machine for what you were doing. Galvanized steel is a nasty bugger o weld. Not sure of the numbers you are giving for speed and voltage. what gas are you using?

[dvice]

25 % and 75 %... I think it is argon and co2 ....it is made for welding steel. I was thinking id up the amperage till I got too much frame melt!! then back off a little...but that didn't happen and I had a 1/4" of bubble gum over the whole weld edge...It was melted a little into the frame...but it just didn't seem to have the heat needed.. maybe ill try some ungalvanized steel at home tonight and see how it welds.. dvice

[fabricator]

Correct on the gas, Try a few practice beads on some flat clean metal. It may have been you didnt grind all the galvanize off.

[MMW]

I have a MM250. For this size material I set it at approximately 21-22v & 38-40 on the wire speed. This is using .035 wire with 75/25 gas.

It is very possible you didn't get the galvanized all off or if outside it could be windy? Try some clean steel with no wind. Do you have a door chart for settings? Polarity hooked up correctly? Ground clamp to neg. mig gun to positive.

[dvice]

I have a MM250. For this size material I set it at approximately 21-22v & 38-40 on the wire speed. This is using .035 wire with 75/25 gas.

It is very possible you didn't get the galvanized all off or if outside it could be windy? Try some clean steel with no wind. Do you have a door chart for settings? Polarity hooked up correctly? Ground clamp to neg. mig gun to positive.

ok, so maybe I thought I didn't need more feed, but I actually do!!.....it was outside, but no wind to speak of. the settings are what the machine came with...

dvice

[ryanjones2150]

I have the MM250, its a solid machine with, in my opinion, a harsh arc and tight sweet spot. Once you get it dialed in, mark the dial with a soap stone for your general short circuit and spray arc settings, should get you close most of the time. When I get back to the shop tomorrow I can try and take a picture of how mine is set up. I know when I first got mine into the shop, it gave me fits, especially out of position. I'll tell you this, it loves to spray arc, but that's no good out of position and probably too hot for what you're doing anyway. The things to check have been mentioned, but I'll hit them again...

...the ground to neg for solid wire.
...Ground clamp on bare metal, not galvanized metal...the "pop pop pop pop" when you start off means you have a bad ground connection.
...good gas coverage, 20 should be fine.
...short stick out.

For something like what you're talking about, I think I'm around 18-19 volts, but I'm running .035 wire. If you can't get it, just stick weld it. When you're welding aluminum, are you using a spool gun?

[dvice]

I have the MM250, its a solid machine with, in my opinion, a harsh arc and tight sweet spot. Once you get it dialed in, mark the dial with a soap stone for your general short circuit and spray arc settings, should get you close most of the time. When I get back to the shop tomorrow I can try and take a picture of how mine is set up. I know when I first got mine into the shop, it gave me fits, especially out of position. I'll tell you this, it loves to spray arc, but that's no good out of position and probably too hot for what you're doing anyway. The things to check have been mentioned, but I'll hit them again...

...the ground to neg for solid wire.
...Ground clamp on bare metal, not galvanized metal...the "pop pop pop pop" when you start off means you have a bad ground connection.
...good gas coverage, 20 should be fine.
...short stick out.

For something like what you're talking about, I think I'm around 18-19 volts, but I'm running .035 wire. If you can't get it, just stick weld it. When you're welding aluminum, are you using a spool gun?

yes on the spool gun.....

dvice

[ryanjones2150]

So here's my starting settings for short circuit and spray arc:

SS-speed 20, volts 19
SA-speed 50, volts 30ish

Tried to upload a picture, but this new site and my iPhone still aren't friends. I marked my dials with a soap stone and I generally don't have to adjust it. When it do, it's just a skosh.

Hope that helps!