TheSamba.com :: View topic - Millermatic- welding problem.. Help!

Thu Feb 16, 2006 6:04 am

I've got a Millermatic 175 mig welder-I'm welding some new rear qtrs on my bug. Probably 20ga metal or so. Finally got the heat and speed dialed in, #2 heat-40 speed. Sometimes the beads will flow nice and smooth and sometimes they'll pop and sputter and not want to lay down. When this happens sometimes the wire will arch back at the start of the feed tube in the machine and will break. I'm using co2-argon gas and #24 wire. Is this a bad ground issue or somthing else? Any help would be much appreciated.

Thu Feb 16, 2006 6:07 am

First off, getting the parts as clean as possible will help. The popping happens when impurities try to enter the work space, or when oxygen tries to get to the work space. Keeping out of the wind or drafts will help.

Thu Feb 16, 2006 6:42 am

I'n working inside so I don't believe drafts are an issue. What do you wipe the weld area down with to clean it? Have you ever had the wire arc off down near the feed roller?

Thu Feb 16, 2006 7:11 am

I had a similar problem with my millermatic 135. For me it was ultimately a wire feed problem. It would sometimes slow up allowing the arc to travel back up the torch. Very erratic, Very annoying.

I disassembled the wire spool shaft and sparingly applied some thick grease to all the moving parts. Although most of it was plastic it still could not overcome the friction no matter how loose I had the wingnut with a big spool of wire hanging on it..

This worked for me.

Thu Feb 16, 2006 8:35 am

I have limited experience with MIG, but have a LOT of experience with TIG, all kinds of metal. The spattering means a definite instability in the arc, and like Hophead said, wire feed could be a problem.

Most of the time I weld with Argon and Helium, rather than CO2, but CO2 works fine, and is better with Argon.

To clean the metal you have to take the film of crap off the surface by roughing it with something.. at least heavy duty scotchbrite or something. Clean clean clean, really helps until you learn how to control better. It's practice that makes you good. I've welded miles and miles of brass, alum, mild steel, stainless, and some carbon steel too. Lots of silver soldering on brass too.

Thu Feb 16, 2006 8:36 am

I don't have a Miller, so the mechanism may be different than my Lincoln: if the tension on the feeder mechanism isn't right, that's what mine does.

Thu Feb 16, 2006 1:20 pm

Do you have .24 tip, drive rollers and guide tube to go with your .24 wire?

Thu Feb 16, 2006 1:30 pm

If none of the other things check out..are you sure you have the spool of wire on the right way?

Thu Feb 16, 2006 7:07 pm

Jowlz wrote: If none of the other things check out..are you sure you have the spool of wire on the right way?

I took my welder on a trip once in my trailer and did not tape the spool of wire very well and it spagetti'd all over the place. I managed to salvage the spool the best I could but could not all of the wire wound back perfectly so it binds up once in a while. It shows the same symptoms. I have to spin the spool a litte in reverse to loosen up the wire a little and it will work fine.
If any of you are asking why I didn't just replace the spool, I'm a cheap bastard and it was a pretty new 10lb spool :D

Fri Feb 17, 2006 5:44 am

I am running a .24 tip and the narrow groove on the drive roller. Should there be just enough tension on the spool so it doesn't keep spinning and snarl up when you stop feeding? I have some Picklex-20 on hand and they say it makes for better,stronger welds when applied b4 welding takes place. Would this be good to clean the bare metal with? Thanks again for the replies.

Fri Feb 17, 2006 7:05 am

i've been using a 175 for a while now with no problems. If its arcing all the way to the spool you more than likely have a grounding problem. The wire tensioner should be set so you can still pull the wire through the tip of the gun with needle nose pliers(welder off!)Is the polarity set right for gas welding? It can be reversed for flux wire by switching the 2 wires in the box above the feed. I find that 24 wire strikes an arc easier on less than perfectly prepped metal than 30 or higher. the pop/hiss is def from poor prep and leaves your welds porous and brittle. Telltale sign is the black or brown sometimes whitish scorch marks around the welds. I also run the wire speed on the miller closer to 6. At 4 you may be burning up the wire faster than it exits the tip especially if you hold it real close to your work. When it arcs out does it foul the tip?

Fri Feb 17, 2006 11:43 am

bubblehead, thx for the input. I do get the blackish, brown scorch marks when it's welding poorly and the copper tip does get blackened as well. I think I tried turning up the wire speed but was burning holes thru the metal. The polarity is set correctly. What tension do you run the pinch roller that feeds the wire? Mine is presently at #4 or so. Is this the tension you're referring to when pulling it out W/ pliers and the units off? Or are you referring to the locknut that holds the wire spool? When butt welding 2 pieces is it necessarry to ground both pieces?

Fri Feb 17, 2006 2:26 pm

Saggs,
I bought a video from Eastwood called Mig welding with mild steel with low current sets, he showed a neat way to set the tension on the wire, if I can explain it properly, turn the unit on have your glove on and place your index finger in front of the gun touching the wire sticking out , pull the trigger with your other hand and adjust the tension roller until the wire comes out and it will start to loop past your finger, another very important thing to mention that was pointed out on the video was saftey, after welding never leave the garage after your done welding for at least 20 mins, fire prevention

Steve

Fri Feb 17, 2006 7:05 pm

I run my wire tensioner at about 3 1/2 on my millermatic 135

Sat Feb 18, 2006 6:25 am

Saggs. I just went back and read your original post. It definitely sounds like not enough tension on the feed. Sounds like you loose your arc, the wire keeps feeding until it runs into the panel. Then its backing up and slipping through the tensioner, making a tangled mess at the spool. Stault is onto it with the Eastwood thing. Put the tip against something non conductive like a block of wood, your gloved hand doesn't sound like the best idea. The wire should feed like crazy even pressed against something. if it slips back in to the tip your not tight enough. Blackened tips and cones are normal. You dont need to ground both panels but striking an arc on the grounded side is often easier and the clamp should be pretty close ( less than a foot) from your arc.

Sun Feb 19, 2006 1:33 pm

I have the same setup: welder, gas mix, and wire.
When I've done welding on 20-22 gauge sheet metal on buses, I've found that the best setting is no. 1 for heat and, of course, a slower speed for the wire. At higher heat it is easier to blow holes in 20 gauge sheet metal and if the speed is too fast it will cause problems with the wire hitting the metal.
My mig welder has the felt held on the wire by a clamp near the spool where oil is squirted on it to lubrcate the wire. Also, make sure that the gun has the correct tip, keep it clean, put an anti-spatter gel on it, and, as noted above, make sure that it has the narrower guide tube for the .024 inch wire.