MIG Help Needed

[Wayne Presley]

Using a Miller 175 I'm not getting the weld results that I'm looking for. I;m usins the .024 wire and 75/25 gas. Mostly welding 16 ga steel tubing from 2-4". Any suggestions on settings? Here is a test part that the lead end of the weld is high and the tail end is a small depression. What can I do to get a more uniform weld?

[down19992000]

what is your gas setting at? Looks like a lack of gas resulting in porosity. Try somewhere between 20-25 cfh as a starting point. And make sure the metal is clean and rust free. You can also have to much flow that will actually create a venturi effect that will result in porosity in the weld.

[Craig in Denver]

I agree that you have a shielding problem. All of that brown shouldn't be there when using gas.

In order to fill the crater at the end of your welds, stop at the end of your bead for a second, before letting off the trigger.

[RetWelder]

Just my two cents

Too much of a leading torch angle * I try to stay in the 15 degree range* * push the torch don`t drag it* can draft air into your weld causing the brown smoke. Too much or not enough gas flow can cause the brown smoke.
Contaminated gas or a hole in the gas hose can cause the smoke too.
Too much stick out *contact tip distance to work piece* * I like 1/4 to 3/8ths of an inch*
Many of these newer multi purpose welding machines do not have enough inductance for my liking, especially when running hard wire. * inductance helps to flatten your weld bead, Basically more penetration.
Weld bead appearance is basically technique *I use the stitch method*, Moving your weld wire the distance of the weld puddle from front to back and increasing your travel that same distance with each puddle. * The best I know how to describe it*
Running hard wire on a flat piece of metal and getting some nice appearing beads is hard. Try a but weld with two pieces and V`d out at 30 to 45 degrees you will find you have better luck with appearance. When ending a weld do not let off of the torch trigger until the end of the bead has sufficient buildup to prevent the dreaded weld bead crater.
Gas flow is pretty much welders choice within reason. * I use 15 C.F.M.* * indoors no wind!* * outdoors breezy 20 to 25 C.F.M.* Gas, 75/25 mix is my preference for mild steel and short arc process.
Welding is a "what works for you scenario within reasonable parameters"
Other may have more suggestions
hope this helps

[mooseman63825]

Mig Help

ok time for me to throw in my two cents worth of advice here,

i prolly run close to 3 miles of wire a night lol at work,

im taking this is prolly solid wire not flux or metal core,as far as the porosiy goes i agree with the rest of the guys as to check your gas i would recommend about 18-24 nice round area there.

as far as the bead appearance well alot of that comes with practice,
but from what i can see you are running to cold turn your heat up or wire speed down, are you looking for a convex or flat weld face on the weldment

im not so sure about the 10-15 degree torch angle and say 15 to 45.

before i an go any farther i would need to know the joint ur welding and such

try setting your gas to about 21 cfh and for a ripple look draw small circle really small circles

[Wayne Presley]

Thanks for the advice, I'm sure that I was pulling the bead and the gas flow was about 15 or so. More practice today.

[hogan]

Wayne Presley,
Maybe it's just me, but I don't see any respectable porosity. What I am seeing is that you should try to clean your mill scale or use a filler that is more forgiving. As mentioned by others, your amp/volt settings look off. Try turning up your voltage or turning down your amps/wire feed speed. Try one or the other, but only one at a time. this will flatten out your weld. Your gas flow should be about 25 to 35 CFH.

[SundownIII]

Gas flow, for a small mig, should NOT be between 25-35 CFH.

Not only is it grossly wasteful, you're blowing so hard you're bound to draw in surrounding air.

Inside, with still air, a CFH rate of 15-20 is more than adequate for a small mig.

[FusionKing]

Looks to me like for a beginner yer doing fine. I've seen a LOT worse. Just put in more time and you will learn more.
Start making actual joints on 2 or more pieces instead of running beads in the middle of stuff and you will see a big difference very quickly in your abilities

[down19992000]

Wayne Presley,
Maybe it's just me, but I don't see any respectable porosity. What I am seeing is that you should try to clean your mill scale or use a filler that is more forgiving. As mentioned by others, your amp/volt settings look off. Try turning up your voltage or turning down your amps/wire feed speed. Try one or the other, but only one at a time. this will flatten out your weld. Your gas flow should be about 25 to 35 CFH.

You dont see any porosity???? Look at the bottom weld on the left it has two or three pinholes within the first inch or so and then farther down it has more that are slightly bubbled. I bet if you hit it with a grinder that particular bead would be full of porosity.

[davedarragh]

Gas Flow

Here's how to settle the gas flow question. If you hold the gun next to your ear, and squeeze the trigger, do you HEAR a "puff" of gas coming out? If not, the hose may have come off inside the machine. This is common with those models when the gas is turned up too high. Also check and make sure the gun is tight inside the machine. Lots of times it will work loose (pulling on it, dragging the machine around), and the gas is "missing" it's path through the gun.

I speak from experience with a MM140 AutoSet.

Dave

[mooseman63825]

mig help

i forgot to note in there that the 35 cfh is for absolut worst conditions and also mainly used on really heavy gauge wire like 5/64 flux core lol, in my defense i had just gotten off work when i posted that and had been there for 15 hours lol

so my bad lol

[lanceman73]

more power

More gas and I don't see any under cut. Turn up the amperage/voltage.

[hogan]

Gas flow, for a small mig, should NOT be between 25-35 CFH.

Not only is it grossly wasteful, you're blowing so hard you're bound to draw in surrounding air.

Inside, with still air, a CFH rate of 15-20 is more than adequate for a small mig.

SundownIII,
Obviously I have wasted the last twenty years of my life. All of that time spent welding, reading technical manuals, mechanical testing, and reviewing/talking to filler metal manufactures was a waste. All I needed to do was talk to sundown. So others do not make the same mistake as I, please do not read the attachment stating a 30 to 50 CFH recommendation by the manufacture.

http://www.mylincolnelectric.com/Catalog/consumabledatasheet.aspx?p=7052

[hogan]

You dont see any porosity???? Look at the bottom weld on the left it has two or three pinholes within the first inch or so and then farther down it has more that are slightly bubbled. I bet if you hit it with a grinder that particular bead would be full of porosity.

I did make a typo. I stated that there was no respectable porosity. I meant to say there was no rejectable porosity, according to AWS D1.1 criteria. I did see it. It's just that these type of discontinuities cause very little problems for weld integrity. Sorry for the mistake