Ok, Mig welding sanity check....

[ChristianHF]

I purchased a new Mig machine 2 weeks ago and have used it both this weekend and last. Last weekend it ran fine aside from occasionally it would act like the wire speed was suddenly slowing without any interaction with the control knob what so ever. Went through the usual diagnostics, didn't make any headway, asked on a few boards and it was suggested I check the liner. Pulled the liner a few days later, found it crushed slightly. So to keep my project going I went to the LWS and purchased another put it all back together and figured I had the problem solved.

So welding today was a little more frustrating. The machine would alternate between acceptable and very porous welds, almost like the gas was intermittently turning on and off. The gas was on the whole time, flow meter was set for 20 CF/Hour, every time the trigger was pulled (that I was watching) the flow meter ball would float up to the 20 CF/hour mark but the weld was behaving like there was no shielding gas. 75/25 argon/CO2 and the same bottle that was making clean, non porous welds last weekend. So again I started diagnosing, checked my ground, cleaned it down to bare metal and tried again. Same result. I checked that the machine end of the gun was seated fully, checked that the o-rings on that end were in tact and they were. Again, intermittent porous welds. I looked at the cable closely and noticed it appeared to have been crushed in the same spot as the liner. From what I could tell from what I was able to find on the internet it appears that the gas flows around the liner in the cable and I have to believe that this is now my problem. I have nothing in the shop that could have crushed either the liner or cable like this and I know to not walk on it or roll over it with anything, so I have to assume shipping damage.

Anyone think I am on the right track here or is there something else I should be checking? I want to make sure the problem isn't on my end before going back to the manufacturer with this. Thanks in advance for the help.

Chris.

 

[davedj1]

What type of metal were you welding both times? How thick and how hot were you welding? I'm no expert but I have noticed I get the same thing every now and then but only when I have the machine cranked right up and am doing some heavy welds. Do you have a purge mode? If you do, check to see that you have gas coming out.
Keep us posted.

 

[Paul N]

Could it be that the gas is leaking out through the damaged spot on the cable? If so, you could try taping it.

If your welding outside, it doesn't take much of a breeze to blow away your shielding gas. Or even indoors with the fan from a heater.

 

[ChristianHF]

The material was 16 gauge hot rolled mild steel, slightly rusty but clean on the cut edges which is what I was welding on. I tried varying the voltage from 17 to 18.5 volts all with the same result. (this was the suggested range on the miller weld calculator) I couldn't feel any gas coming out of the orifices, but 20 CF/hour isn't much flow and didn't think it would be something I could feel. Am I incorrect on this? The unit doesn't have a purge mode but I am willing to waste some wire and gas exploring this angle if it is believed this might be the issue. I was welding inside, near an open garage door, but there wasn't a breeze at all and no fan. Wire is ER70 S6 Sorry I forgot to include this originally.

 

[ericher69]

You couldn't feel any gas can you hear any when you press the trigger? Turn the wire speed way down and hit the trigger while keeping the nozzle near your ear. You should feel and hear 20cfh.

How's the pressure on the tank/regulator?

Your reg/pressure gauge may be broken and the bottle is near empty??

Just trying to help

 

[joshuabardwell]

I don't MIG, so excuse me if this is dumb, but could you back the wire out of the liner and back onto the spool, then take the spool out of the welder and run tests on the gas without spitting wire and wasting it?

 

[Mark @ Everlast]

What machine is this. With the exact numbers you gave on voltage, it would appear to be an import machine? Is it an Everlast? If so, there are a couple of things I'd check. One, is to make sure I was using the right size drive roll. The other is that you might need to double check that the wire is riding IN the groove and not in between the grooves. And if it is our machine, the gas is in lpm not cfh.

 

[Paul N]

You should be able to hear and feel 20 cfh. That's the setting I use. To test flow on my welder, I release the pressure on the drive rolls so no wire comes out. Then pull the trigger and hold it up to your ear, then your lips (don"t touch your lips). If there's no flow at the nozzle, and the flow meter shows there is, then I would say you have a break in the line between the valve and the point of attachment to the cable. It could be a loose connection or a crack in the line. Either way, it doesn't sound too serious. Just take the side panel off and start snooping. One more thing. On my Miller, where the cable plugs into the machine, there are 2 O rings for the gas. Another simple and cheap fix.

 

[ChristianHF]

The bottle is about 1/2 full, reading about 900 psi on the gage. The flow meter is brand new and the gauge seems to function correctly and is in SCFH. I will take the flow meter off and crack the valve to check it out today. I will also check the flow with it connected if the pressure in the tank checks out. Thanks again.

Chris.

 

[bikerdib]

My vote it that the hose is damaged and either blocking flow or leaking. I agree with others, either release all tension on the drive roller or turn the wire speed all the way down and listen.