I know this information is out there, but I couldn't find exactly what I ws looking for.

I was welding my charge pipes with flux core and everything was going smooth, no holes, good clean sealing welds. I ran out of .035 flux wire, and got some regular .035 wire. So I turn the gas on, try a couple different flow rates, all the different heat and wire feed settings. Seemed that no matter what I did the weld would lay smooth for about 1 second (less on faster wire speeds) then immediately start getting wavy and catching air or something. The end result would be a ton of holes in the bead (and a much taller bead than with the flux).

My only thought is that maybe I need .030 wire instead, but before I go out and buy that only to discover the same thing happens, I thought I'd post here and see if I could gather some input. I welded with gas before and didn't have this problem, don't know what changed since then though.

 

did you use the same tip and diffuser and nozzle?

 

Ya.. it's the same ones I've used from before when the welds turned out good though, so I'm hesitant to blame that. Guess it still could be though. Do you think the .035 wire shouldn't make that kind of difference from .030?

 

i dont think that would be a problem, its hard to say it seems like your not getting gas to the weld. did you try to listen to the whip and see if the gas is coming out?

 

ya, definitely heard it okay

 

I'm not sure if this will help, but here goes. I have a lincoln 135 MIG and experienced the same problems you had when switching from flux to gas, holes and just plain shitty welds. Then I read the manual and discovered that you have to switch the wire polarity when welding with gas as opposed to flux wire. The wires on my welder are just inside the cabinet next to the feed roller.

CN: read the manual its good for joo

 

yes thats correct good thinking

 

Oops, I thought htat was only when switching to aluninium. I'll double check the manual when I get home

 

Also if you switched FCAW to MIG along with changing the polarity you also need to change out the sleve in side of the welding gun's cable... At least thats what the instructions for my LE weld pak say and even the instructions that come with the mig conversion kit for my welder say that clearly... hence that is why they provide one with the mig conversion kit... im sure your welds are getting contaminated..

 

Yup, probably didn't switch the polarity. Most machines I've encountered you don't need to change the liner of the cable, just the nozzle on the gun. Only time I've needed to change the liner is when switching from a steel wire to an aluminum wire.

 

Gotcha, thanks guy