mg vs. fluxcore welder-is it responsile?

By dorpaul Date 09-23-2005 02:37

Hello,
I am new to welding and new to this site. I purchased an 80 or 90 amp Marquette Welder. I've attended a welding course, however, I used a much larger and professional welding machine. Ever since I have used mine it seems to want to sputter.
It's the wire feed mechanism that sputters. If I point the gun up in the air, then the mig wire comes out steadily and at the right speed correctly. It's when I am pointing the gun at my work that the wire feed
'sputters'. In fact, the entire wire feed mechanism is jerky. The prolem is in the molten puddle I think. The sputtering is actually the wire feed cutting off and on rapidly (I think).
Today, I happened to purchase a spool of fluxcore wire that is also .030 size. And today I tried it on my welder (with no gas tank, of course) and it seemed to work fine!! Finally, I think I'm getting penetration!!!
So, my question is: What was I doing wrong earlier? I had tried .024 and .030 mig wire that I had just purchased from Lowe's. I was attempting to weld 14 or 18 gauge galvinized sheet metal. Of course, I had to reverse the wiring to convert the machine from gas to fluxcore. I had een using 75% argon gas. I know Im inexperienced, however, I should have gotten a steady feed or mig wire.

Can someone please help. I've got noone else to ask.
Thanks,
Paul Dorsey

By Lawrence (*****)

Date 09-23-2005 02:50

Usually self shielded flux core wire for those little units is designed to run DC- While GMAW is DC+ Your little machine most likely has a polarity stud inside that needs to be switched when processes are switched.

It's only a guess but since the FCAW is working well than it may have come stock set at DC- .... One way or another your owners manual can set you straight on that issue.

By dorpaul Date 09-23-2005 20:52

Lawrence,
Thanks for answering! The polarity switch was done from the start, so that is not the reason that the wire feed mechanism 'stutters', and is not smooth when I use regular mig wire (using 024 & 030 mig wire).
The ffact that it is smooth when I use fluxcore wire kinda leads me to wonder if perhaps the line carrying the gas from the machine to the nozzle might have a puncture somewhere? (I am hearing the familiar 'hiss' that the gas makes at the nozzle, however.)
When reading my texts they say, "use fluxcore for windy conditions, and it also makes for a 'dirtier' weld" however, none of them say that, "it is any easier to weld with", (as is my case).
Paul

By billvanderhoof (****)

Date 09-24-2005 06:25

I don't know why flux core feeds better than hard wire but it could be that the fact that it's a tube makes it a little easier to deform so that the feed rollers can get a better "bite". The fact that the gun position has an effect says that the wire isn't feeding through the gun smoothly. If you haven't, try a new contact tip. Remove the diffuser (the next bit back from the contact tip) see if it has gotten packed up with wire shavings, clean or replace if necessary. No help yet you may need a new liner. More feed roller tension may help.
Bill

By dorpaul Date 09-24-2005 13:44

Thanks for the help!
The only thing I meant when I said, "the regular mig wire comes out smoothly when I point the mig nozzle up and away from my work" was
to say that, 'the sputtering only occurs when I have the mig wire correctly pointed (in the molten puddle)'. Of course, this is when I need it to feed smoothly instead it 'sputters' (like perhaps 10 times per second as the wire feeds out.)
Paul