Welding Tips and Tricks

I need some wisdom. I bought a TWECO 211i right after they switched the name from Thermal Arc, so it's been a few years. I've struggled with the mig function on this machine since I got it. So I have mostly used it for smaw if any real welding needed to be done.
The starts are the problem. It is just horrible. Sputtering, popping and burning the wire off into the tip, not starting the arc, or cold starts (and porosity) for a second or two and then it takes off and welds ok. So I've replaced the ground clamp, upgraded the ground cable, changed wires, tips, checked the gas flow, checked the liner (which hasn't been used much), tried increasing wire speed and voltage way higher than what should be needed. I've become anal about keeping my ground as close as possible and clamp on bright bare metal, and the problem persists. It acts like a bad ground or bad connection closing the circuit.
The machine, other than mig starts, seems to function correctly, all the controls work, tig is good, stick is good and it runs good with 7013, 6011, 6013, ER308, and 7018 is real nice. But the mig is pissing me off. The only thing left is either something is wrong with the gun or the machine is defective.

I have regretted selling my HH180 ever since I got this one - it ran so good. I've just about decided this invertor machine sucks and I want to go back to a transformer HH190.

Anyway I'm just about to give up unless there is something I've missed... has anyone else had these problems and found a fix?

Thanks, Clif

I haven't used that machine, but there was no mention of what drive roller you are using and if it is the appropriate one, how much pressure you are using on the follower roller, and how much drag you have set on the spool. The two latter no one here will be able to tell if you did it correctly no matter how well you describe it. It has to be done "in-person", and it has to be "just right". It's just one of those things that you have to learn with experience, just like "looking at the puddle and not the arc" kinda things.

Thanks Oscar, I rechecked the feed drive and I'm using .30 L56 wire on the smooth V .30 drive roller. Tension is set per the manual at just enough to not have the wire slipping. Wire roll tension is set just enough to keep the roll from continuing to spin when the trigger is released. I think i'm going to try the knurled drive roller.

One thing I noticed looking at it again tonight is that the tube for the wire to enter the drive is aligned to the outside edge of the wire roll. It's on there per the manual, but it looks like it has to make a sharp turn to come off the roll and enter the drive. I may try to fabri-cobble some kind of spacer to move the roll over and eliminate the turn.

The saga continues...

caltom wrote:Thanks Oscar, I rechecked the feed drive and I'm using .30 L56 wire on the smooth V .30 drive roller. Tension is set per the manual at just enough to not have the wire slipping. Wire roll tension is set just enough to keep the roll from continuing to spin when the trigger is released. I think i'm going to try the knurled drive roller.

One thing I noticed looking at it again tonight is that the tube for the wire to enter the drive is aligned to the outside edge of the wire roll. It's on there per the manual, but it looks like it has to make a sharp turn to come off the roll and enter the drive. I may try to fabri-cobble some kind of spacer to move the roll over and eliminate the turn.

The saga continues...

You really shouldn't need to go to a knurled roller. That's not a solution.

Try to see if there is an adjustment to get wire feeding better into the drive. It shouldn't be making any sharp turns as you mentioned.

Also, how long is your stick out at the starts? Are you keeping/trimming the wire mostly flush to the nozzle with each start? A long stick out at the start can create issues in the first couple seconds as you mentioned.

Do not use a knurled roller. That is for flux-cored soft wires. A knurled roller with solid MIG wire will leave lots of metal particles/shavings inside the liner making things worse.

Make sure the wire is actually sitting in the groove right before the follower roller is set down on it. Because wire guides have some tolerance to accommodate several wire diameters, it's very possible the wire is not in the groove and simply sitting on the flat part of the drive roller when you set the follower down on it.

Typically the wire guide should be "pointed" to the center of the spool so the wire doesn't come all the way from one side. If it is coming from one side due to a misalignment that will put extra friction within the wire guide and more strain on the drive motor.

I did more checking today. I tried to get a picture of how the wire has to cross the reel to get into the guide. I dont think that helps. The wire reel has a hole that a pin sits in to secure it to the tension hub...

Then I took a close look at the gun and found that I could not push on the the tip hard enough to compress the liner for the tip to contact the diffuser. I know its supposed to be a little long so that the nozzle compresses it, but I don't think it's seating fully. So I'm thinking the liner is too long and may be the source of the trouble.

After looking at it more, I don't think I like this style of contact tip that just sits on there, or the large diameter of the nozzle. I'd prefer a screw-in style and smaller diameter tapered nozzle. I found an HTP gun that should be plug-n-play for $120.

So three more questions:
How can I space the wire over on the tension hub?
I've never cut one, so i assume I can use a cut-off wheel to shorten the liner?
Does anyone have an opinion on the quality of HTP stuff in general, or their mig guns?

I know this is an old thread, but I was doing some searching on the web because I am having the same issue with my Tweco Fabricator 211i as you're describing. Was wondering if you found a solution to your issue, as I found mig welding to work just fine on 115v not on 230v.