Mig Gone Haywire

Franko

Franko

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I traded in my old faithful Lincoln 175 MIG last summer and thought I upgraded to a Hobart Handler 190 with a spool gun, hoping I could weld aluminum with it, having tried a Lincoln 225 TIG a few years earlier and failed miserably.

The first month I had the new Hobart, I practiced with the spool gun on aluminum and wasn't very impressed with it. It was a beast and very difficult to control and I melted a lot of aluminum.Isost faith and purchased a Miller Syncromatic 210 and practiced with it for few weeks, giving TIG another shot. I practiced with it for several weeks and got distracted on a pressing job.

Meanwhile, the Hobart MIG sat idle for a few months. I didn't try welding steel with because I didn't think it would be a problem.

I had a project to weld some big steel, so I fired up the new Hobart Handler.
I fiddled with it for a couple hours and didn't even come close to making a good weld. I gave up, put it away and did the job with the Miller TIG.

The problem I was having was pourous and pitted welds that were just stacking up and not blending on the edges.

I have another project where I'm welding a heavy duty steel. I always made good welds with my Lincoln 175, so I thought I'd give MIG another try. I was sure I could figure out whats gone haywire. I spent a couple hours this afternoon and the results were dismal. I didn't even come close to making a good weld.

I tried everything. Check the gas flow, hoses and connections, clean the tip, high amps, low amps, fast wire feed, slow and in between. Nothing worked.
It didn't sound right no matter what adjustment I made. It was the old bacon sizzle, but it was very loud and aggressive, maybe like a string if fire crackers going off. It was like it was blowing it out.

I'm using .030 solid wire with CO2/Argon. I used .023 with the old Lincoln.

The welds all stacked up too high and didn't penetrate around the edges.

I'm at my wits end. I could sure use some advise.

Here is a pic of the last of the test beads. These represent the gammot of adjustments, yet pretty much all the same ugly. These represent amperage between 40 and 70 amps and wire feed between 3 and 7, It's on 3/16" hot roll angle. I used a high speed wire brush to clean up the steel, and even wiped them down with acetone.

mig beads_0458.JPG
 
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I gave up on the MIG welder because I wasn't making any progress on trouble shooting. Since this job needs to be welded, I fired up the TIG and almost immediately was making fairly acceptable welds.

These aren't the prettiest TIG work, but I think they are sound and have good penetration.
There are some black beads at the edges of the beads. They are hard and shiny. They won't chip off. I've never seen this before. I power wire brushed rust off the steel and it was pretty clean, and I also wiped them down with acetone.

weld beads_0457.JPG
 
Those look an awful lot like gas flow problems to me. I'm no pro welder, but I'd double check everything gas related, including the gas itself. I wouldn't think the supplier would mismark the cylinder, and I don't know of a gas that would give that result, but that's not impossible. You do this outside on a windy day? With the drive roll disengaged, can you hear gas at the gun when triggered? What is your flow?
 
Is it possible that your MIG is set for the wrong polarity ? It sounds like it is set for flux core wire.
 
Have you checked the polarity? Electrode positive. Gas flow 15 to 20 cfm. Is the whip pushed all the way into the socket at the feed rollers. If its not fully in the oring for the gas will not seal. It looks like gas issues. Can you hear gas flow at the nozzle? The welder should have a chart on the inside of the wire cover. They are usually pretty spot on.

Master of unfinished projects
 
Just a thought has all of your mig welding problems been with the exact same cylinder of gas? Can you verify that it has what it says in it. As in did it come from your local weld supply. any friends that are welders. In just a few minutes they should be able tell you what's up with it if it's just setting.

Master of unfinished projects
 
Franko said:
I power wire brushed rust off the steel and it was pretty clean,
Click to expand...

Hi
I like to grind the steel, the cleaner the better, get the rust & scale off.
look an awful lot like gas flow problems to me.
 
No gas is what it looks like. In fact, the first bead I ran I forgot to turn it on. After I turned it on, subsequent beads did not improve. It has to be a gas leak somewhere.

I'll recheck my gas line connections, but I'm pretty sure they are ok.

It is the same cylinder I was using with the Lincoln, so I don't think there is anything wrong with the gas. I haven't replenished it since I got the Hobart.

I'm sure the polarity is correct. That was the first thing I checked.

I was working inside my shop with no wind. There is a small fan turned way down low in the back of the shop, but barely a wiff of discernible air movement at the welding station. The TIG welds were done at the same place with no problems.
If breeze was the problem, I'd think the TIG would have shown it more as it seems more sensitive to wind.
I've MIG welded outside in a pretty good breeze and never had these kind of problems.

I use a flow meter which showed gas was flowing. I couldn't hear it at the nozzle, so it is possible it isn't making it to the nozzle. Usual gas flow is 20 cfm. I even tried cranking it up to 40 with no change.

I'll double check the whip connection. That's a good idea I didn't think of. I think I'll also check the gas hose and connections inside the welder. If That's it, it could explain why I was having trouble with the spool gun, too.

I was using argon with the spool gun when welding aluminum.

This was driving me crazy. I've always been pretty good at MIG.

Thanks for all the good ideas. You guys are the greatest.
 
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