Problems with mig welding

I do a fair amount of mig welding using a newish millermatic 252. Most material is cold or hot rolled 1/8 to 1/4 in thickness. Current setup is .030 er70s2 wire and 75/25 argon/co2 gas. I'm having terrible problems with a little ball forming on the end of the wire after I let go of the trigger. Gun is a Bernard q300. I've messed with the "burnback" settings on the welder to no luck. Any help would be appreciated. Thanks

Jason

What settings are you using for example --- on the 1/4 material -- IPM and Amps - gas flow -

If your welds look fine, there is not a problem. I often snip the end of my wire fresh before moving onto the next weld. Then sometimes I don't, it just depends on what I am welding on.

I mainly use the settings on the welder. Its worked so far for me. If I want a little hotter weld I just dial it up. I know i can also snipe the end and honestly the welds are good. Really the only problem is its hard striking an arc for the next weld if the little ball is there. Just trying to save a step. I have noticed its not a problem with the little ball is still hot. I can light right back up.

I like to weld on the hotter side too so the weld is deep penetrating but also has a flatter profile and looks good on the surface. If I have a weld that is visible and I have to start cold, I snip the end of the wire and always strike arc about 1/8th inch forward of where I normally would then wash the weld backwards and run over the start with the continuous weld bead. This is a pretty fast movement to whip the weld back over the start point before starting forward with the weld.

go to Lincoln
download there PDF for your wire type
use there settings.
don't look back.

wb

I use a Millermatic 251P with the M-25 gun. 75/25 gas & Esab Weld 70S-6 wire. I've always snipped the end of the wire, without regard to the type or brand. Fresh end always seems to start better.

JT

Yep, same for me , I just snip it off.

Too high a voltage setting will always leave a ball when the the arc is extinguished. Try turning your volts down 1 volt at a time..the wire should "pinch off" to a no ball condition eventually. I teach welding...most novices are usually 2- 4 volts too high for a given wire speed[amperage] setting.

I also have a Millermatic 252. I use .035 wire with straight CO2 and it will sometimes make a ball on the end of the wire after a weld. I simply snip it off to about 1/4" from the tip with welding cutters before starting another pass. I also use welding gel to keep the spatter down from the CO2 and my tips are recessed by 1/8" with the Miller outer cover made for that dimension. The Millermatic 252 is a great machine. too. It does 1/2" steel with no trouble.

Alphonse said:

Too high a voltage setting will always leave a ball when the the arc is extinguished. Try turning your volts down 1 volt at a time..the wire should "pinch off" to a no ball condition eventually. I teach welding...most novices are usually 2- 4 volts too high for a given wire speed[amperage] setting.

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I don't doubt that most people run MIG hotter than they need to, but I find it hard to swallow that you can drop voltage until it no longer balls and maintain the correct welding spec to make a good penetrating weld. It would seem to me that you could have a balling condition and be too cold for a thick metal joint and not have a balling condition and still be too hot for running on thin sheet metal.

Honesty i don't even give it a secound thought, i set the juice at what i want it at for the material thickness’s im welding, wire speed so she runs nice and burns in suitably and go from there. Ball or no ball, the advice about striking just infront of your actual start is spot on.

Yeah i spose that may well put me into the bit too hot camp, but at least there im not in the bit falls of camp :-) I generally prefer to run mig as hot as i can for a given job, IMHO its the most risky welding process going, its very easy to be too cold and lack penetration yet still have a ok looking weld. Weld on the hotter side of things and that risk disappears.

I agree with you greenbugy. Most MIG welding is done too cold. Remember that heat is amps x volts= arc watts[arc heat] Increase wire speed will increase amperage, Voltage increase will also add heat, but not as much as wire speed increase will. The man asked how to get rid of the ball at the end of wire...and I told him how. Our welding school is a Lincoln sponsored program. A key welding engineer told us this pearl of wisdom about voltage. It has to do with how the short arc transfer process pinches off droplets of metal from the wire and leaves the last one on as a ball. He stated that the larger this ball is, the more excessive the voltage is in relation to the wire speed. The MP 350 machines have a setting mode 11 that sets the proper voltage for whatever wire speed setting. Example 200IPM will set the voltage to 16.8 Run a bead, good, slight ball on end of wire or no ball who cares. I like a volt or so more say 17.5-18. welds better but [again who cares ball will be a bit bigger.] I have seen students welding with excess voltage around this wire speed at 19-20 volts and giant ball on wire, excess spatter, hissing arc. So the moral of the story is "does it take balls to make a good MIG weld" Take care all! love+love=love welding!