MIG welding settings

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Hi all,I know this a bit of a vague question as personal preference and style will dictate somewhat. Id like some help with dialling in settings.I have a 240v 250amp Kemppi MIG. I run gas with it and 0.9mm wire (0.035) Im welding some 1/8 plate (hot rolled) onto 1/8 box section chassis. I did some dummy runs with the plate and some 2x4 RHS.Weld is a lap fillet. Postions will be flat, horizontal and vertical (probably down hand for me) I dont weave or whip, just straight push mostly.Id like to hear what Voltage and wire feed guys would be using for this.cheersSerg
Reply:1 amp. per .001 of thickness,and sand all of the rust and scale and wipe with acetone.I used CR on mine, welded with my old Miller 120 mig.Can use A36 also but it's dirty as HRS is.
Reply:This might help you. http://www.millerwelds.com/resources...calculator.phpDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Thphtm, that's not going to help him much with a unit where you only set the voltage. I will agree with the practice of good prep.At the tech school running 92/8 Argon/co2 on 1/8" using .035 we go anywhere from about 17.5v up to 20 roughly using XMT 304's. Wire speed on the feeders about 180-225 roughly. The lower end being vertical up, the upper end being flat, where you could run even higher if you have the skill. Skill level plays a huge part in this. I prefer to tend to weld on the lower side and go a bit slower compared to some, but then I don't do production welding where time is money. However I can crank the voltage up and run almost all three positions up in the 19- 19.5 volt range depending on joint type and prep. The big key is being able to read the puddle and manipulate it to accomplish what you are trying to do. With the volts up that high, I'd really have to hustle doing say vertical and I'd have a really tough time doing gapped but joints. Filets or laps would be much easier.Sounds like your use is "structural", so I would not suggest running vertical down as that limits penetration. If you run vertical down, you'd have to really up the voltage and wire to compensate for the loss of penetration by "adding" the heat "manually". Most guys I've seen who try running vertical down at the right settings can't handle the extra voltage needed to produce good penetrating welds. Vertical up may seem harder, but it does allow you to slow down a bit and have more control.Edit, Sorry CEP you posted while I was replying to thphtm's post. Down side of Millers calculator is that it tends to be set up for production settings on some things.Last edited by DSW; 06-11-2014 at 07:54 AM..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 DSWEdit, Sorry CEP you posted while I was replying to thphtm's post. Down side of Millers calculator is that it tends to be set up for production settings on some things.
Reply:Thanks for the replies guys.My gas is BOC Argosheild Light, which if I have read the specs correctly, is Argon 91.9%,  Carbon dioxide 5% and Oxygen 3.1%.Hot rolled steel is all that is easily locally available. If I wanted cold rolled I would be ordering it and having to buy whole sheets or lengths. I always remove paint, rust and mill scale and wipe clean. My welder has 2, 4 postion switches for voltage. The book that came with it gives me the voltage for each combined postion. Wire feed is in m/sec. I take it you guys talk inch/sec?I played around with some scrap yesterday to try and get my settings right. Same thickness etc as I will be using. I found that under 22v the weld just looked to proud, i.e. sitting on the surface. But my wire feed was probably a touch low at about 160IPS (when trying say 19v). I will have to get some more scrap and try going back to the lower voltage and uping the wirer feed. I also found that for me, vertical down is safer. I have never had someone show me the correct technique and settings for up. There is only so much you can learn from reading, and having a crack can lead to frustration as many things can be wrong with no idea. So far it seems that maybe im running my wire feed a touch low for given voltage..Hopefully these pics will help:1st - Angle bolted to bracket sits on chassis flange and gets welded along lower edge:2nd - Bracket I made and will be welded to chassis. Face of chassis web gets welded via the large trapezoid hole. Ignore welds along outside legs, that was me playing with my tig for the first time:3rd - Front of welder: Attached Images
Reply:I cant seem to edit my above post. I had a brain fart and wrote meters/inches per second, should be per minute.So I set up some more test pieces and tried the voltage and wire feed settings posted here and by the miller calculator. Well I dont know whats going on but way too much wire feed for the respective voltage settings??? I dont know if the chart in my owners manual is way off for the voltage settings with switch settings but see the pics below for me efforts. In all settings I did a run and then just tried same voltage with adjusting wire feed (not in pics) each test got better with lowering the wire feed. Both the 17.8v and 19.5v seemed low voltage wise, that is sitting on the surface no penetration. 1st pic is 17.8v and 180 IPM.2nd pic is 23.8v and 320 IPM (miller calculator spray transfer)3rd pic is 19.5v and 200 IPM Attached Images
Reply:Leaving the voltage at 23.8v and just having a quick play with the wire feed I got the below results. This is at 227~300 IPM. Top weld in each pic is in the flat postion the bottom weld in each pic is horizontal.Any tips to help me better them will be appreciated. Attached Images
Reply:Id also like to hear about gun set up. I run my contact tip about 1/8 inside the gas nozzle and probably run the end of the gas nozzle 3/8 from the weld. Am I close here?
Reply:Originally Posted by husq2100Id also like to hear about gun set up. I run my contact tip about 1/8 inside the gas nozzle and probably run the end of the gas nozzle 3/8 from the weld. Am I close here?
Reply:I can change my set up over to 0.6mm close enough to 0.23, but Im not changing gas. This is not a business for me just a hobbie. Up until very recently we were not allowed to own gas bottles so have to rent them and pay for gas refills. Im still stuck on this atm and not paying $$$ just to play around.
Reply:Understood. Watch the gas pressure if you're indoors. Less is better. Gas is both a blessing and a curse. There is a "comfortable" range to keep the weld clean. More pressure ruins it and not enough gives a "dirty" weld(porosity/wormholes). Get plenty of scrap and just play with it. Take notes.Make your own "door chart(s)".You will like the .023. You can move slower on the thin metal. After 1/8 go to . 030 and at 1/4 ++ go .035. I never weld with larger wire, even on thick steel. You lose control. I enjoy "sewing" with a MIG.NOT MIG like TIG. More of a "more caulking here for strenght" kinda thang.Thats why Wallah invented stick welders. I have a bad MOFO(MM200) but when the over 3/8+ shows up, I grab an electrode holder and fire up a stick machine.Main deal ? Have fun ! If you fear the weld will fail get some self tapping screws and add to the circus. I often weld AND bolt.........just because.Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:Last beads posted aren't too bad. I see a few minor things, but nothing too major. Practice will most likely iron out what I see. One thing you will have is some issues at that voltage if you run vertical up. You'll find it's probably difficult to control well.With that gas mix, you'll be able to go up into spray mode.  That explains why your last set of beads look so nice and smooth. It's pretty easy to make nice beads in spray with a bit of practice, but out of position beads like vertical up and overhead will be almost impossible as runny as the puddle will be. Horizontal results will be mixed. Horizontal fillets and maybe laps won't be an issue for the most part, however but joints, outside corners and even some fillets may be tough depending on your settings.As far as tip location and the distance from the work, that varies. What is really key is what is referred to as "stickout", the distance from the tip to the actual work, ignore the nozzle right now. The closer you have the gun to the work, the "hotter" the settings for any given voltage/wire speed setting. The farther away, the "colder". You can end up with similar results with the gun farther away, if you adjust the voltage/wire settings. 23v is on the high side of what I usually have students use, but then your stickout is a bit longer, backing the "heat" down some, probably back into the upper range of what we run. I suggest the students maintain about a 3/8" stickout, however I've had some students who simply couldn't manage to keep it that short. In those cases, I let them find what works for them on stickout, say 1/2", then adjust the machine to give acceptable results. One down side with longer stickouts, is that gas shielding can be more difficult. Keep in mind with the higher voltage, you have to use more stickout so the wire doesn't fuse to the tip. When running large fluxcore wire at really high voltages stickouts as long as 3/4" isn't unheard of. You need that distance to keep the tip away from the weld and not over heat it.Now we are on to part two of your question about the nozzle. Typically we keep the nozzle flush with the tip. However when using a longer stickout, say with that 1/2" example above, moving the nozzle out some can help with gas flow. Even if the stickout is 1/2", with the nozzle out 1/8" past the tip, you get about the same gas coverage as you would if you'd used a 3/8" stickout. I know a couple of auto body guys who prefer to use a fairly long stickout. The reason is with thin sheet, they have a bit more heat control that way. If they pull back farther, they can cool the bead and avoid burn thru, move in more and they can get more heat. The extended nozzle helps them avoid issues with porosity in their welds because the stickout is too long for the nozzle they have at that gas flow..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:thanks again,I will try playing with stick out and see the change. When you give your measurement for stick out, are we talking to the point of the wire were it is melting (face of weld almost)? or to the internal corner/face of material? I know that may be silly question, but there is at least anough 1/8 there???I get what you are saying about voltage, spray and position, Problem im having is I just cant see how my machine set at 17-19.5v is going to get correct penetration in any position for this material thickness?? I could have got those voltages looking better by dropping the wire feed speed (lower than the pictures above) but felt it pointless as it was just too cold IMO.Id love to set up a voltage display that could tell me the actual voltage. Is anything like this possible to retro fit?Gas im running at 17 LPM (litres per minute) what do you guys run?Also just to add I "push" not "pull" . That is, I am right handed and weld from right to left. I usally only run about 10-15 degrees angle off vertical (direction of travel) I found that laying the gun over more than that can give a pretty weld that looks good, but when broken, penetration was not there.Ill do some more tests this arvo.cheersSerg
Reply:All we teach is push with solid wire. Mostly because #1 several of the companies who hire out of the tech school use this to keep heat input down for a number of reasons, #2 because it's easier to teach people to drag after they have learned to push vs the other way around.When I say 3/8" I'm usually talking about flat material. Fillets are a bit more difficult to explain, usually because you go from "close" on one side, to "far" in the very toe, to "close" again on the other side, even if the actual change of distance isn't really all that great. You need to see what works for you.Remember "penetration" doesn't always mean you melted thru to the back side. Fillets are measured on leg size. Even with perfect settings you never burn thru say 3/8" material when laying a 3/8" fillet. The actual depth of fusion is much less than 3/8", but the weld is still structurally sound. Even with tight butted but joints, It's really tough to get 100% penetration with the "correct" settings. To go all the way thru, you have to turn up the machine high enough to burn thru. "Normal" settings that would give you a solid code quality weld with a gap would leave you with poor penetration on a tight butted joint.Lincolns Procedure handbook of arc welding can explain in more detail what makes an "acceptable" weld and how things like voltage and so are are determined. It's a great reference book and well work the money, but it's not the easiest read.http://www.jflfoundation.com/Product...ProductCode=PH.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:Thanks DSW,I played around a bit more today. With my gas nozzle pushed all the way back it was still about 1/16 proud of the contact tip, no big deal. I think I would have been close to the 3/8 stick out as I was talking from contact tip any way, but played again trying to stay closer and more control. definitely no further than 3/8, probably a touch closer. I tried the lower voltage again and adjusted wire speed. I still have no clue how you guys are welding 1/8 plate lap fillet at such low voltage??? It would be great if someone could do a couple runs in the 17.5-19v range and post the pics.I stopped in at a mates work shop and discussed a digital voltage display for my welder. Piece of cake for him, he actually gave me a small display to take home and try out, bugger me if the owners manual is spot on with in 0.1V! so that throws that theory out the window.I was able to drop down one click on fine switch, back to 22.6v and thats about as low as I would go and feel comfortable for now. I had my wire speed at 167 IPM, gas at 17LPM.these 3 pics are of the same one weld, flat position, 4 inches long: Attached Images
Reply:these 3 pics are of another single weld, same settings, vertical down, 4 inches long (start/top was right side working downward to left side): Attached Images
Reply:Your consistency looks really good. I'd have to do some destructive testing on the vertical down beads to tell how well the penetrated. However not all welds really must be "structurally" sound. Many times if you just need to hold 2 pieces together in a non structural application, they are most likely more than good enough.Unfortunately I don't have access to the XMT 304's right now at the tech school since school is out. It won't be until fall again when I have a chance to "play" with a machine that actually shows voltage. A lot of my welds look very similar to what you show. I just stay in tight and take my time..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:Ill do some vertical downs on one side and peel the plate off and post the pics. That book you linked, it referrers to arc welding.  I take it it covers GMAW as well?Ill also try and add a pic of my high tech voltage display lol.
Reply:Yes it covers mig/ FC, tig and stick. Probably also covers submerged arc and spot welding as well, but it's been a bit since I leafed thru my copy and those areas I wouldn't have had any interest in.Lincoln has quite a few good books for sale relatively inexpensively at that site..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