rookie welding mistake

Igino

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Hey guys,

I have been trying to learn how to weld with my Miller DVI2

http://www.millerwelds.com/products/mig/millermatic_dvi2/

Its a nice welder, and I feel like an idiot because I can't get good welds. The problem is that all my welds turn out extremely dirty (brown). I was trying to figure out what was wrong - so I turned off the gas and the welds come out the exact same (making me think this is a gas issue). HOWEVER - when I close the tank and pull the trigger the pressure in the dial dissipates...so gas is leaving - i just suspect its not going where it needs to go! I took the back cover off, and couldn't find anything visibly disconnected. Any ideas?

I am running 25 CFM 75 Argon 25 CO2

Thanks as always!
-Igino
 

loufish

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You should be able to hear the shielding gas come out from the end of the MIG gun....
Usually if there is not gas delivery the welds get very porous...

I did get a contaminated gas cyl once, no matter what I did the beads didn't lay down correctly and where a little porous...Finally exchanged cyls and all was good...possible, but not likely
 

Igino

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interesting - I don't think i've heard that. Even if it were contaminated I would still be able to hear it right?

Is anyone familiar with this family of welders, that could tell me what could possibly be causing these symptoms?
 

Chase 2

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If you turned off the gas and the welds are exactly the same you obviously are not getting enough gas coverage at the nozzle. Hold the nozzle near your ear (not at your ear) and pull the trigger, as said you should be able to hear the gas flowing. Check the supply line all the way through the machine, it could be leaking off at the solenoid that controls the flow from the tank to the gun.
 

Igino

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great idea - i'll check this out, and get back to you.
 

partybarge_pilot

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What wire are you using? If you mistakenly have the flux core crap in it, your welds will look the same regardless of shielding gas presence.
 

tmathews

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Also, make sure you are running 25-30 cuft per hour.... anything less is not good.
 

archangel2003

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There is also the issue of the negative and positive because flux core and straight MIG (compared to each other) used reversed polarity.

Check the manual and verify the correct polarity.

Also, make sure the right gas is being used.
 

NicksTrix

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be sure the gun cable is all the way in the socket so that the gas ports are in line properly.
tell us what you find out after checking.

yes bottles do come contaminated sometimes, pretty rare but it does happen.
 

Goltzwagon

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Some lower voltage welders come set up for flux core wire, and on Flux core -the polarity is reversed. Make sure you have the correct polarity set up on the welder if you are welding with gas and non shielded wire. (the - + wires inside the unit)
 

Igino

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NicksTrix nailed it - the gun cable wasn't all the way in the socket....thanks for all your help guys!
 

robertharman

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NicksTrix nailed it - the gun cable wasn't all the way in the socket....thanks for all your help guys!
Was going to suggest the same thing. I have done the same thing. I have also had a bottle with a bad mix before.
 
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