Newbie MIG question - beads like worms

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I need help with my attempts to learn MIG welding. My welding beads look like worms crawling across the steel.Background – I took an intro to welding class at my local voc-tech (highly recommend). We covered a bit of GMAW welding. I was encouraged enough to get a used Miller 130XP welder off Craigslist. It came setup for FCAW. Did a some of that but got tired of all the splatter. Purchased a bottle of Argon/CO2 gas and got new ER70S-6 wire.To figure the right setting for my welder I have been laying a number of beads on a piece of 1/8 hot rolled steel plate. I started 0.030 wire and the recommended voltage tap of 4   with a wire speed of 50. The bead was a bump on the metal. To my untrained eye it looks like I’m too cold or too fast a wire speed. I all the settings around it trying to narrow it down without success. I then thought maybe 0.023 wire would work better and switched over to that. Very similar results. Below are the resulting welds. Left side is 0.023 wire. Right side is 0.030 wire. Voltage taps and wire speeds are indicated. How come the welds seem to sit on top rather than flatten out? If these were real welds I would have to spend all day grinding them flat.I tried butt welding to 1/8” plates together. Same large bead. Weld seemed OK. I cut it apart with my saw and bead and plates seemed to mix together well.What am I doing wrong?Thanks for any comments and suggestions. Attached Images
Reply:It's too cold. You're gonna have a rough time getting enough heat out of that machine for 1/8
Reply:You need to try welding something like a tee or lap joint in order to get a some penetration going with that machine on 1/8 th. A butt joint will yield the same results as running a bead on a flat piece of plate, unless the plates are bevels or gapped slightly.  The root of the weld needs somewhere to go, and with a 110v machine and material that thick the weld will just pile up.
Reply:I've had alot more luck running flux core on the high end of what those machines can do.
Reply:If you were welding flux core before and did not change your polarity when you switched to hard wire, you will need to.6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:Top 2 beads on the left look the best of the bunch, but I'll agree they look a bit tall from what I can see.As mentioned 1/8" is pushing that machine to the max. It's doable under perfect conditions with good prep, but you need to have everything right to do so. The manufacturers all over rate these little 110v migs. To get the maximum out of those little machines, they need as much input power as possible. That means they really need to be plugged into a 20 amp 115v outlet that has nothing else on that circuit ( dedicated). If you are running on a 15 amp circuit, a circuit that has other things plugged into it, or are using an extension cord, chances are you aren't getting all the input you could, and it is limiting the machine some what. The breaker doesn't have to trip for the power to be limited. You could be running right under the tripping point, but still have a loss of line voltage due to the draw or an extension cord.Also as mentioned welding tight but joints or simple welds on flat plate will give you the tallest beads because there is no where for the material to go and that machine doesn't have the output power to heat the material enough to flatten them out more.I see some nice consistency in several of those beads, especially 3/65 on the right, and the top 2 on the left. Nice work and keep practicing. Just remember to stay within the limits of that little machine and you will be fine..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:U said it came with flux core, did u switch the polarity for solid wire with gas?Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Thanks for all the replies!I did remember to switch the polarity going from flux core to gas, but thanks for the reminder. I am using a 20 amp circuit so that's OK. I am using an extension cord. While it is 10 gauge, it is pretty long. I will try plugging the welder directly into the wall and see if that gives me even a little more power.Would pre-heating the steel with a oxy-acetylene rose bud tip help? Or would it cause more problems than it solves with stuff like warping?Maybe the real message is get a bigger welder. The manual for my 130 says it can handle up to 3/16". Sounds like that is more marketing hype than real capability. Will a 180 machine be able to easily weld 1/8" or should I be looking for a 210, 211, 252 type machine?Thanks for the help. You gave me a few things to try and a few things to think about.
Reply:Some things you can do1. Plug it into the wall as mentioned2. Grind off the millscale3. Drag vs push4. heat the base metal (kind of a waste of gas for practice)If you plan on working with metal at the high end of what any machine can do you will start running into duty cycle issues. 110v machine have some of the worst duty cycles maxed out. If you primarily work with thin sheet then a 110v mig is just fine.BTW I looked at the manual for your machine and 50 on the wire speed is for straight CO2 not argon mixes. Check the chart for C25Last edited by Snuffy; 11-08-2012 at 12:47 PM.
Reply:Snuffy's last post pretty well covered it, a couple of other points:A MIG bead in the middle of a flat sheet will almost always look thick because a MIG welder is always adding metal when you are welding, and the way you increase current is to increase wire speed- which gives you more metal!When welding 2 pieces of 1/8" sheet together, you should have a gap of 1/16" or so between the 2 sheets. If the 2 pieces are butted closely together you will have a high bead with poor penetration.Preheating will help when you are near the upper limits of your machine, and it doesn't have to be extremely hot- 150 - 250F should be plenty.HTH,JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Originally Posted by SeattleKentTMaybe the real message is get a bigger welder. The manual for my 130 says it can handle up to 3/16". Sounds like that is more marketing hype than real capability. Will a 180 machine be able to easily weld 1/8" or should I be looking for a 210, 211, 252 type machine?.
Reply:Originally Posted by SeattleKentMaybe the real message is get a bigger welder. The manual for my 130 says it can handle up to 3/16". Sounds like that is more marketing hype than real capability. Will a 180 machine be able to easily weld 1/8" or should I be looking for a 210, 211, 252 type machine?Thanks for the help. You gave me a few things to try and a few things to think about.
Reply:Update:I ran a couple of tests. First I tried plugging the welders into the dedicated 20amp curcuit instead of using the extension cord. The first picture below is the result. I see little difference. The wall 4/75 is thinner because I went a little faster. The 4/60 beads look identical. So either my wall amperage is low or there is so little voltage drop on the 10 gauge cord as to not be an issue. Too bad, I was hoping for an easy fix.Note: All were drag welds(I can see the puddle better). Next I tried preheating with my oxy-acetylene torch. I heated enough to get some water drops to just boil. The second picture below shows the result. The pre-heating did make a difference. The preheat seems to have better penetration as evidenced by the larger area of discoloration around the bead. The trouble was the steel plate began to wrap. The 16" plate now has about 3/4 of an inch of warpage. I'm sure there is some way to evenly heat without the steel warping, I'm just not good enough to do it. Finally, I tired welding some 1 1/4 angle iron. I cut at 45 degrees and tried to make a nice 90 degree corner. This went better. I suspect the big steel plate sucks a not of heat. The smaller angle iron has lower mass and does not take all the heat away from the weld. The weld was better but not great. Probably good enough to build my welding table.Tomorrow I'll try grinding or etching off the mill scale and see what difference that makes.Note: Sorry about the curving beads. I have a difficult time seeing anything other than the puddle or the arc. I cannot see the base metal or the cooling bead as I weld. I suspect it is just a matter of practice to get straighter beads. Thanks for reading. Comments and suggestions are really appreciated. Attached Images
Reply:Bigger haz is not better. All it really means is you are moving slow and warping the plate more. I'de take off the millscale before preheat any day. Both where I'm welding and where my ground clamp is goin. You want the best electrical connection you can get. And a marker or soapstone that contrasts along with some back lighting will straighten things right up. It'll be easier once you've got something to follow.
Reply:Originally Posted by SeattleKentUpdate:I ran a couple of tests. First I tried plugging the welders into the dedicated 20amp curcuit instead of using the extension cord. The first picture below is the result. I see little difference. The wall 4/75 is thinner because I went a little faster. The 4/60 beads look identical. So either my wall amperage is low or there is so little voltage drop on the 10 gauge cord as to not be an issue. Too bad, I was hoping for an easy fix.Note: All were drag welds(I can see the puddle better). Next I tried preheating with my oxy-acetylene torch. I heated enough to get some water drops to just boil. The second picture below shows the result. The pre-heating did make a difference. The preheat seems to have better penetration as evidenced by the larger area of discoloration around the bead. The trouble was the steel plate began to wrap. The 16" plate now has about 3/4 of an inch of warpage. I'm sure there is some way to evenly heat without the steel warping, I'm just not good enough to do it.
Reply:At a mere 130 amps your machine just doesn't pack enough current to MIG weld 1/8. You're realistically restricted to gauge thickness sheets only.For reasons i won't discuss here, MIG tends to produce significantly less heat input at any given current rating, than stick.So, for example, you could easily weld 3/8" plate with a 130 amp stick welder, but with a 130 amp MIG you barely have enough power to go past 12 ga.
Reply:Originally Posted by JoshfromsaltlakeAt a mere 130 amps your machine just doesn't pack enough current to MIG weld 1/8. You're realistically restricted to gauge thickness sheets only.For reasons i won't discuss here, MIG tends to produce significantly less heat input at any given current rating, than stick.So, for example, you could easily weld 3/8" plate with a 130 amp stick welder, but with a 130 amp MIG you barely have enough power to go past 12 ga.
Reply:Just welding in the middle of a flat doesn't do much for you in the real world anyway. It's great for getting a go/no-go range for sure if you're changing wire sizes or types but once you start with an actual fit up you might be close or may be way off. I use a scrap piece of flat for a quick set up but whatever settings I use won't mean much untill I hit something close to the configuration I'll actually be working on. I can set it up to look fine on a flat then blow an open corner with a slight gap all to he11 and gone or just the opposite on another joint config."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt