Millermatic 140 Penetration Problems - 1/8"

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Hi All,We are a student organization at the University of South Florida. Our department was able to provide us with a Miller 140 with autoset. First, this is the only machine we have access to, so please don't say "use 220". The machine is plugged into an outlet with nothing else on it, though we have no access to the panel to see if its a 20 amp circuit.We are planning on having several of our team take a welding course at a local community college, but that doesn't start for 2 weeks.We're trying to weld 1/8" mild steel plate. The panel in the box says we should be using 65 for the wire speed, and 10 for the voltage settings. We have completely cleaned the steel, but seem to be having penetration issues. The weld looks pretty ok (for total newbs) but when we go to bend it, they often break in half and you can see a lack of penetration. We have tried running the pool straight down the crack, pausing 1/2 second between each surge, sort of turns out looking like dimes, as well as the v pattern. We seem to actually get better penetration with staying right on the seem, but the weld is much thicker with the v pattern.We're using 75/25 gas (set at 20) and .030 solid wire. Another thing I noticed is that if I set it on autoset, when I'm done welding (only about 1.5" test strips) there is a significant length of wire hanging out of the gun. Does this mean that I've got the manual settings for wire feed to low, and that I'm not feeding wire directly into the puddle fast enough?We are holding the wire approx 1/16" from the metal when we strike, and we're welding horizontally, pushing, not pulling. We are still using the stock ground clamp until we can get a better one, but we have cleaned the plate steel we're using to weld on as well, so hopefully ground is still decent. I read that bacon sizzling sounds are bad for aluminum, but can't find anything on steel, ours makes that sound as we're welding.The contact tip is slightly protruding from the nozzle, but since we can't get the nozzle on any further, the contact tip isn't fully screwed into the fitting, is this normal?Pictures will be posted as soon as I can get the camera to our shop.Thank you for any help. Sorry for so much information, but I hoped to cover all the bases.ASME@USF
Reply:BTW, there is very little soot in the welds (good gas coverage?), but there does seem to be quite a bit of spatter for what I read i'm supposed to get with solid wire. There also seems to be a fair amount of porosity in some of the welds.
Reply:when i initially bought my lincoln 180c i had to switch polarity.. i would say check that to start with..  it might be initially set up for flux core wire...  check your manual...tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:I'm 99% sure it's right, according to the manual. we checked a bunch of times, but no reason not to recheck.Thanks!ASME@USF
Reply:Assuming you are welding a groove butt joiint, I suggest you bevel the edges of your joint to a 45° included angle aprroximately 1/16" deep. The other choice is to use .035 filler metal which will require a higher heat input and thus increase your penetrtaion or use a fluxcored wire such as E71-T1.
Reply:I knew there would be something I would forget. We're trying a T-joint as it seemed to be the easiest looking thing to try.Most of our projects will be thinner than this, so that's why we bought the .030, this is all the scrap we had laying around though. I'll go pick up a small roll of the larger solid wire.
Reply:I would stick with the .030 solid wire or go to an .035 flux cored wire. Are you using an extension cord? Tanker
Reply:the 030 is what the guy at the distributor gave me, he said it'd be the best for beginners.Yes, a 14 gauge 30' extension cord. retractable, and mounted to the ceiling. I mentioned that we have no access to the panel to see what kind of plug we're in. Can that make a lot of difference?
Reply:We also have a 220v plug in the shop, not 100% sure if it works. Is it safe to use one of the 220/110 adapter plugs and just use that plug, or would there be too much current?
Reply:0.030 solid wire is -generally- a decent 'match' for 120V MIG machines.  The MM140 specs say it is for 0.024-0.030 solid wire anyway, so trying to use 0.035 solid wire probably isn't the way to go.The contact tip slightly extending past the end of the nozzle is usually normal for 'small' machines and wires.  Big stuff (machines and wires and amps) may be different.Double-check the polarity.  Solid wire steel is DCEP (gun is + and work clamp is - ).But you are trying to push the machine to its upper amp and volt limits for welding on 1/8 inch material.The machine just doesn't have the 'snot' to run 0.035 solid wire (amps or volts) and is at its upper limits using 0.030 solid wire on 1/8 inch thick material.The 'bacon sizzling sound' is usual and normal and desired for short-circuit transfer mode GMAW.For practice and starting out, may I suggest taking your 1/8 inch material and practicing on a lap joint.  Easy to set up (just clean the steel and clamp two pieces flat on top of one another in a lap joint configuration!    ) and you can see (and watch and look for) how the arc melts the material and the puddle fills in behind it as you travel along.Watch the puddle, not the arc itself!If you will be working on thinner material than 1/8 inch steel, maybe pick up a roll of 0.023-0.025 (same stuff for all practical purposes) solid wire.  That size wire is also a good 'match' for most 120V GMAW machines and also for 'thin' sheet metal thickness projects.Yeah, the manual says voltage setting 10 and WFS of 65 for welding with 0.030 solid wire and C25 gas, so you are or should be at (or close to) the right settings.Porosity could be a (small) leak somewhere in the gas lines (it doesn't take much of a leak to F things up!) or a breeze/draft blowing the shielding gas away while you weld.Oh, also the CTWD (contact tip work distance) should be about 1/2 inch.  1/16 inch is too close for GMAW (that's more of a GTAW arc length  ).Practice, practice, practice.  If none of you already know how to weld, ask around and see if someone else (other student or faculty) KNOWS how to use a GMAW machine and weld.  Or just wait the two weeks and take the course.  Also, 'clean' steel for welding means clean all the way to bright shiny steel.  No grease or oil, no paint, no rust, no mill scale.  Some welding processes can 'tolerate' certain amounts of crud, but you ALWAYS get better results when you clean things well first.  Sometimes you get no or bad results if you don't clean well enough (GTAW aka TIG is that way).In addition to the manual for the machine, you can also check the MIller www.millerwelds.com or Lincoln www.lincolnelectric.com or ESAB www.esabna.com websites for LOTS more info and tips and such about welding (theory and practical).  The best laid schemes ... Gang oft agley ...
Reply:MoonRise,THANK YOU. That was very detailed, and we'll look into all of it. We don't really have access to any trained personnel. That's why we're leaving the university to take proper training at a technical center.I wonder if pushing the gas up a little higher than 20, maybe 25, would help with the porosity then. We'll back out of the weld a bit to 1/2" and see what happens.There will be lots and lots of practice going on...I'll let everyone know how it goes.We have been cleaning with a steel wire wheel attached to a drill. Do we need to do any special chemical cleaning like for aluminum when using steel?we'll be transitioning to aluminum for our current project, but definitely wanted to start with steel.thanks to all for such quick responses.ASME@USF
Reply:1/8" on a MM140 with solid wire/gas is doable, but you are pushing the machine to it's max. Anything that will reduce the power coming into the machine will possibly drop the performance down below the acceptable level. Thats why they want you to use a 20 amp dedicated outlet. 15 amps is often not enough, and other items drawing off power on the same line will cause issues also. Another would be voltage drop due to small size extension cord/long length. In many cases you'll trip the breaker showing you the machine is trying to draw more power than the system is capable of giving, but other times you might just get down graded performance and not trip the breaker. Honestly I'd be surprised if this was the only outlet on the breaker unless this was originally designed as such. Also note that you must stay within the duty cycle of the machine as well, and it's very small on max power. You will often get degraded performance once you weld past the duty cycle on the machine. It will still weld, but there's often a noticeable drop in performance once past the duty cycle.Proper joint prep and cleaning will help greatly. For a T joint you could gap the T by a 1/16" or partially bevel the intersecting plate. Both are somewhat of a pain to do with material this small. I've never really played with the auto set myself. If this was me, I'd use the max setting of 10 for your power and turn off the auto set and adjust the wire manually. For starters I'd run one at 10/60, 10/65 and 10/70 with the .030 wire and see how it runs and what gets you the most penetration..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:Miller's "Tips for MIG" indicate you will get BETTER penetration with pull. I thought I read push gets you better penetration as you pre-heat the upcoming portion of the project.Thoughts?
Reply:A wire wheel doesn't do a good enough job for steel prep. All it does is polish the scale and rust. You want to clean with a grinding wheel or better yet a sanding disk for thin material and get down to shiny silver metal..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:Originally Posted by DSWA wire wheel doesn't do a good enough job for steel prep. All it does is polish the scale and rust. You want to clean with a grinding wheel or better yet a sanding disk for thin material and get down to shiny silver metal.
Reply:For steel all I do is wipe off any loose material after grinding. The only time I'll use anything else is if there's a lot of oil on the steel from the mill. If so I'll remove the oil before grinding with acetone or another solvent that leaves no residue. Simple green and dawn soap and water works well for large amounts of stuff that needs to be deoild. Note Brake cleaner is NOT a good way to remove oils. It can form a lethal phosgene gas when heated if there is any left in joints or crevices. Here's a thread with a link to the dangers of brake cleaner.http://weldingweb.com/vbb/showthread.php?t=42596.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:Want to weld?Get an angle grinder (and the associated PPE to go with it!).Clean metal means grind or cut it down to clean and shiny.A wire wheel on a drill really won't do it.  It may get some rust off, but a wire wheel (even on an angle grinder) almost never can remove mill scale (which is a hard form of iron oxide).Cleaning depends a bit on what condition the metal is in to begin with.  It could be as simple as wiping down with some solvent to remove grease and oil, or it could be sandblasting and then solvent cleaning and then a quick grind with some abrasives (grinding disk or flap wheel) and then some more solvent cleaning.  Or other steps.Oh, and if you plan on welding aluminum, that is generally a bit trickier both on the cleaning and prep and the welding as well.  Especially with a 'small' MIG machine, even with a spoolgun, welding aluminum is a bit tricky.  The best laid schemes ... Gang oft agley ...
Reply:re: brake cleaner and weldingAbsolutely be careful!But, 'brake cleaner' comes in different chemicals.  It is always some sort of solvent or solvents in spray can form.'brake cleaner' with trichloroethane + UV from welding = phosgene gas formation = BadThingsYou ALWAYS make sure the solvent from any cleaning operation is gone before welding!btw, the 'new' formula brake cleaner I have seen now is either spray can acetone or spray can alcohol+ketones+OtherStuff.  For quick and easy cleaning and degreasing, spray acetone 'brake cleaner' seems to work OK.Just remember that almost all of those solvents will still burn quite well and may have other health/safety risks.  They just don't form phosgene gas if exposed to intense UV from a welding arc.Always be careful.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by USFASMEMoonRise,THANK YOU. That was very detailed, and we'll look into all of it. We don't really have access to any trained personnel. That's why we're leaving the university to take proper training at a technical center.I wonder if pushing the gas up a little higher than 20, maybe 25, would help with the porosity then. We'll back out of the weld a bit to 1/2" and see what happens.There will be lots and lots of practice going on...I'll let everyone know how it goes.We have been cleaning with a steel wire wheel attached to a drill. Do we need to do any special chemical cleaning like for aluminum when using steel?we'll be transitioning to aluminum for our current project, but definitely wanted to start with steel.thanks to all for such quick responses.ASME@USF
Reply:Originally Posted by USFASMEthe 030 is what the guy at the distributor gave me, he said it'd be the best for beginners.Yes, a 14 gauge 30' extension cord. retractable, and mounted to the ceiling. I mentioned that we have no access to the panel to see what kind of plug we're in. Can that make a lot of difference?
Reply:Dave is right you need a better extension cord to start with. Try dragging the weld as well as this helps with penetration, if you are still having issues after that then look at switching to .035 flux cored wire. Do not plug the 140 into a 220 receptical it will not be pretty if you do.      Tanker
Reply:I wasn't sure if the adapter cords had something that down converted it to 110. Thanks for the info, we definitely will not be plugging it in there anytime soon then.I read somewhere incorrectly that push was for better penetration, we will try pulling tonight and see about that.I'll plug directly into an outlet in the corner on the wall. it has other things plugged into it, but we'll try taking those out. As we share the shop with two other groups, it's impossible to know which outlets may have machines or tools they're drawing off of as well.Thanks to all for the ideas.
Reply:If you short out the outlet and trip the breaker, everyone else who's on that breaker will let you know. Especially if it was important so they could get their projects done and no one can find the maintenance guy who knows were the breakers are... Trust me I've done it.  Instructor finaly gave in and let me stay home to work at my place rather than keep dragging in my industrial tools to the class room or their poor excuse for a "shop"..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:dont use brake cleaner or starting fluid to clean an area you will be welding.. it can simply kill you.. take the machine off that long extension cord, it just wont work to its potential on a 30ft cord, i wouldnt go over a 10ft cord length and make it a heavy duty extension cord.. i would say that the 30ft cord is mostly your problem...tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:If your weld isn't penetrating enough turn it up. If you can't turn it up anymore, preheat the joint.Here are some rules of thumb:Machine Setting hints:1. Remember: the wire speed controls fill and the voltage controls spread. For example, to get a larger weld size, increase the wire to get more fill and increase the voltage to spread the extra weld metal evenly.2. Both the wire speed and voltage can be adjusted independently from each other to change the arc characteristics, if small adjustments are made. However, if large setting changes are made, both wire and voltage must increase or decrease together.3. Once the overall heat level (meaning  the combination of BOTH wire and voltage) is set for the correct weld size, the machine settings should be tuned so that the arc makes a sharp, crisp, crackling noise. If the arc is making a popping sound and droplets of molten metal appear on the end of the wire, increase the wire speed OR decrease the voltage until a crisp crackle is heard.4. It is possible for the arc to have a crisp crackle sound, but to have too much wire OR too little voltage. In the case, weld will appear cold and high-crowned. It will have steep, high sides and will not wet or flow smoothly into the base metal. If the welds are showing high crowns and lack of fusion at the edges, EITHER increase the voltage OR decrease the wire.5. Within the correct operating range, increasing the voltage OR decreasing the wire will give a more fluid weld pool and better fusion.  Within the correct operating range, decreasing the voltage OR increasing the wire will cause the weld pool to fill up and freeze faster, which is helpful in out of position welding.