Noobie help 1/8 steel

[mcauleym]

Hi all,

I purchased a used MM 150 and have been practicing. I need some advice.
I'm using .035 flux core.

It seems like my wire feed rate is not staying consistent. If I tighten the drive roll I find the wire is getting crushed. Do I need a knurled drive roll?

Also, I'm practicing on 1/8 x 1 flat bar. How do you finish without the crater at the end of your weld and the start without the bubble at the begining?

Should the penetration show through the other side of the metal?

Thanks in advance,
noobie Mike

[DSW]

First thing I would do is pull the gun apart and blow out the liner. There may be a bunch of crud in the liner that is causing it to bind. Also look very carefully at the liner itself for any kinks. I often have feeding inconsistency when the other guys in the shop jam my mig in the corner trying to get more space and kink the liner. Also try and keep the gun as straight as possible. .035 is big wire for that gun and it will not like tight bends in the lead.

1/8" will not "show" in the sense I think you mean. You will see a heat mark on the opposite side that shows good penetration but the metal will not burn thru if that is what you are thinking.

[mcauleym]

Don't laugh at my bead lol. I was concentrating on penetration and trying different voltages. I can make them pretty but don't seem to get the penetration.

The gun is a ga17c. I think the machine came with a something something 15.

I made some 'coupons' from this metal and all my 'pretty' welds broke. The ugly ones with high volts and lower wire speed bent the parent metal. Is this normal?

Thanks for sharing - I really appreciate it.

Like my doiley?

[hankj]

We don't laugh at people who are actually trying to learn!:)

Your bead in the first picture is too tall, and looks like rope. Those are symptoms of too low of a voltage setting, and an unsteady hand.

Try to get yourself in a comfortable position, with good support for your gun hand. Don't try to run a "forever" bead. When you've gone as far as it is comfy, stop and reposition.

Try that one again with a bit more voltage.

Don't expect to see a homogeneous weld on the backside unless you left a root gap. If you are welding in "free air" (ie: off the bench with no backing), you can "keyhole" the weld, in which case you will see 100% penetration, but it's tough on .125!:p

Keep on keepin' on. You'll get there, and when you do, you'll know the difference!

As for the stop/start issues, begin about 1/4" ahead of where you really want the bead to start, walk it back to that point, and go.

When you get to the end, slow down a bit and change the gun angle so that you are welding nearly 90°.

Report back! We're here to help.

Hank

[mcauleym]

I think I'm getting the hang of it. I do however turn the machine lower than what the parameter chart says. It says 60% wire, voltage tap #3. Im more like 40% wire voltage #2.

Am I getting better?:confused:

[Altitude]

That looks better than mine.
I started practicing last week too. Im thinking travel speed is an issue with newbies and gun angle too. Notice how much quicker the "frying" sound increases when you move closer and hold the gun almost perpendicular.

[hankj]

Tap 3 is where you should be. See how tall your bead is? Another voltage tao will flatten that a bit. Try it!

Next, cut a cross section of a coupon, smooth it down with either a gringer or sander, and etch it with a weak acid (muriatic or nitric work well). That will show you if you really had penetration.

Hank

[NewMexSmoke]

Have to concur with others. Looks like a little more voltage, "heat" or "push" is what you are looking for. Tall beads can be due to lower than required voltage and/or speed of weld. Looks like you were getting the idea on the furthest bead to the right on the "better1" photo.

Keep practicing. This isn't something most people do well right off the bat. If it was everybody would be doing it.

[mcauleym]

I practiced some more and think I'm starting to get it. All 4 welds (2 photos on 1 piece of metal so I could get close) were on the same settings. All I did was alter my weave and travel speed.

Which is best and why?

Oh yea - I mentioned I had turned down my settings to tap #2 - but the chart actually says #3. Lol I didn't second guess myself and ignored the chart - but I read it wrong the first time! #2 was correct.

I also posted a pic of my machine - MM120 - later rebranded to MM150. It's funny its not listed on the owners manual list so I just use the MM150 docs. Just for interests sake I guess.

Cheers and thanks a lot for your input. Its really helping. P.S. I decided to take a course at my community college in the fall and try stick/mig/acetalene.