Mig Welding Basics 2

where we get into part 2 of MIG welding basics this is where we left off last week setting the machine to the manufacturers chart recommendations for eighth inch steel got a nice sound a nice bacon frying sound but then setting it lower the sound changes get a little bit of a rattle more spatter and we set it even lower all the way down to 20 half the recommended speed and you hear that hissing sound that's way too little wire feed speed contrast that with too much wire feed speed here where the wire is stubbing in the puddle hey Jody here with welding tips and tricks' calm this is part 2 in part 1 of this series on MIG welding basics I ask for comments so if I glossed over things forgot to explain things we could address them later on so today I got a whole bunch of comments on that video so today we're going to try to deal with as many as we can one that I can't believe I glossed over is uh what's the bird's nest you know how do you prevent it so the bird's nest thing it's not like what do I do in case it ever happens it's more like what do I do when it happens so let's talk about what it is things you can do to prevent it Drive roller mechanisms are similar in one aspect and they all have Drive rollers and some type of a feed tube or a guide tube that they feed wire into now this little area right in here this little area from where this pinches the wire to where it enters the the guide tube that needs to be as short as possible so this is set pretty darn close this is a factory setting here this is kind of how the machine came but see there's just not much space right there it could be even a little bit closer so the problem occurs when you've got too much resistance either from a you know too many coils in your MIG gun wrong size you know your tip is messed up got a ball of metal on the end of it restricting the wire feed or whatever but it kinks right here once it kinks once this kinks here from too much resistance somewhere in the gun or tip then it kinks in it it's just going to push wire down in here in bird's nest so to avoid birds nesting there are several things that you can do number one you want to have that little gap set as tight as possible between where the drive roller is pinched and push the wire and there they enter the guide tube also make sure that your contact tip is not credit up with a piece of spatter that's restricting the wire feed also make sure that that you have nice looping bends in your in your cable and you know there's a liner inside this that typically in some guns it's it's it looks just like that guide tube does it's a spiral wound steel cable other guns it's nylon or teflon some guns it's not even replaceable it's just a throwaway the gun is like pitch the gun get a whole nother gun but that liner if it's replaceable replace it at intervals when it gets you know the copper off the copper flash off of typical MIG wires rubs and builds up on the inside of liners and eventually it gets gunky and really hard to push through there we'll talk later on about maybe how to clean that out and to extend the life of a liner or on a Sunday afternoon how to just you know make it work until you can get a new liner all right let's see if we can bang out the rest of the list here pros and cons of short-circuit versus spray versus globular transfer first thing we're going to talk about is short-circuit Meg because that's what most people will be doing in their shops and at home aside from heavy industrial welding short-circuit meg is more versatile than any other type of MIG welding because you can weld in all positions you can weld thick or thin metal you can adjust the machine as you like and you can use really small wires to get down really really thin metal even auto body type panel thicknesses it's not the best for production or coated welds you can fill in a gap easily going downhill just all depends on how you set the machine and you if you use the proper size wire going uphill not a problem vertical uphill welds are not a problem with short circuit Meg they are with spray transfer and we'll talk about that in just a minute all right what is spray transfer it's a different way that the the metal comes off the wire it comes off in fine little droplets and it's really hot it penetrates deeply and it's mainly for heavy thick metal and for production work it's hot it is a qualified process for doing coded work whereas short circuit requires you to qualify the procedure and it's got a deep-penetration profile what about globular transfer well globular transfer is not used much in my there may be some application for it but it's mainly just a bad setting explain the different types of gases used for MIG welding steel and their applications there are lots of different gases that can be used for MIG welding carbon steel but I'm going to talk about the most common ones and starting with straight co2 you need a little adapter usually for your regulator with co2 because the threads are different along with a nylon insulator washer to keep your regulator from frosting up it typically at higher currents it that's not quite as smooth an arc and it gets a little bit of spatter and you can see right there got a little undercut but it's at lower currents with smaller diameter wires even though there is a much tighter sweet spot that you have to adjust and tweak your settings you can get a really really smooth nice arc this particular little repair job was done with Oh 23 wire and then some of the arc shots are using O 30 wire but you can see how slow it is it's a very slow build-up but that it's not necessarily a bad thing if you're not worried about production rates and all that all you're worried about is just making a one-off weld here and there it gives you a little time especially when you're out of position gives you a little time to to make the weld and to reposition yourself alright 7525 argon co2 is probably the most common for short circuit mig welding that's what you'll probably get if you just ask for MIG gas at an air gas store or welding supply store it's very versatile eating you can use it for really really thin stuff like auto body panels with o23 wire or you can get bigger wire you can crank up two bolts 223 or so and and well some pretty darn thick stuff in the sweet spot setting on 7525 is it's much easier to do than on straight co2 it's get much more forgiving a lot less spatter if you don't have it set quite right and again it's it's probably the most common at least it is it is the most commonly used here in the States what about ninety ten where would you use that use that for spray transfer and also for pulse spray transfer no spray transfer is where that wire never does meet the puddle just coming off in little tiny droplets and it's a really good process for coded work and for when you need the penetration you need for there not to be any doubt that you're getting penetration and it's just it's fast and it's hot this is a this is some pulse spray Meg here and pulse kind of buffers it down where you can then weld vertical uphill overhead and everything else to but still get the benefits of spray transfer what about metal prepping for MIG welding it's hard to say across the board one particular level of metal preparation because it varies from situation to situation like there is a lot of rust coating on this square tubing that needed to be cleaned off because I was going to do some TIG welding on it and some MIG welding so for MIG welding if it didn't have rust at all on it I may not have cleaned it at all but because I was going to do TIG welding which requires a lot more cleaning than MIG in general I cleaned up the weld areas to clean shiny bright metal with a flat disc and that makes the TIG welding go a whole lot better than by not cleaning however MIG welding the same joint you know with as long as it didn't have rust on if it just had the mill scale would not have been a problem also anytime you're using flame cutting you need to get rid of the dross you do not want to make weld directly over that oxidized dross surface contamination from oxy-fuel cutting or plasma cutting see that's all nice and clean and shined up also just depends on the criticality of the application this is that you like that buzzword but certain jobs are you know done to code or have inspection criteria and need to be cleaned up in the in the weld area down to clean bright metal anytime anytime you have paint you need to get the paint off of there you need to get it down to clean bright metal but there just it's just all it varies from one situation to another the level the level of cleanliness that is required to get the job done correctly what about duty cycle what does that mean duty cycle is basically the amount of time out of a 10 minute period that a machine can well that a certain amperage without having to let it cool off it can be deceiving because sometimes you might look at a 200 amp machine and it might have be only a 20 percent duty cycle at 200 amps so it might have 200 amps you might be able to use 200 amps for a short time period but you're not going to be able to weld part after part after part continuously at 200 amps this machine is is rated at 30 percent duty cycle at 150 amps now there's also a factor in there what the ambient temperature is and the the the rating the duty ratings usually use 40 degrees centigrade 104 degrees Fahrenheit this is a thermal arc fabricator 252 I and it's more money than the Hobart but at 150 amps so it's a hundred percent duty cycle so you can weld all day long at 150 amps so let's look at a couple of different situations here and where you might need more or less duty cycle here I'm using that Hobart 210 MVP and it's just a little light fabrication job with inch and a half square tubing étoile doing a whole lot of tacking and then when this frame gets tacked all up it gets welded up but I only gonna well a inch and a half at a time before I reposition so the machine gets a lot of time to rest now here sheet metal fabrication a lot of tacking even though it's a lot of welding it's at really low amperage like maybe 50 or 60 amps so having a 30 percent duty cycle at 150 amps not a problem like this can easily be done with a 115 volt MIG welder with a fairly low duty cycle but contrast that to this these 1-inch plates that get welded on the side of these pieces of square tubing and you know you see we used to do orders of 20 of these at a time and once they were to this point I would weld them non-stop pretty much so I never hardly let the Machine rest for more than a couple of minutes and if I had a machine with a low duty cycle where I had to stop every now and then it would have just been counterproductive so you know in production work 100 percent duty cycle sometimes is is the best idea what's the relationship between voltage and wire feed speed one one way of thinking about voltage and wire feed speed is hot and cold water to to mix together to get a certain temperature okay so there's a certain temperature that's a sweet spot that feels good to you for instance in your shower so you turn up the you turn up the hot water and now you turn the cold water to achieve that certain temperature there's always you know if you want more flow you got to turn both you can't just turn one so that's kind of that's kind of it's not the best analogy in the world but that's kind of that's kind of the way that voltage and wire feed speed work there's a certain balance that needs to be achieved and it changes that the settings change with different sized wire and different gases and all that stuff but there's a certain outcome you want and so once you get that arc looking sounding acting the way you want it but if you if you need to go hotter or colder you kind of adjust both down both up to to achieve that that desired effect in the end okay it's just one way of looking at it and in the previous video I talked about a crappy glare what I call a crappy ground clamp so what do I consider a good ground clamp well what's a good ground clamp well this is not it's I mean it works but it's it's not doesn't have much spring tension it's steel that's just plated with copper and when you're welding with it oftentimes you can see a toothed spark and get hot so I don't like I don't like the cheap cheap jumper cable type ground clamps this is a good deal better with it with this copper strap that that joins the two jaws so you keep you from losing a ground if one of them arcs and with other ones in contact you can also pull this out this way and and use it as clamping on the part and then you've got the copper braided wire clamping on your part and that that helps for mig welding also the old school old school solid copper alloy clamps with a nice heavy heavy spring and jaws on them or hard to beat any ground that you use is only as good as the area you clamp it to so you know you got to have that area of completely free of mill scale paint gunk is a 230 volt welder better and if it is why a 230 volt welder is really not necessarily a better welder it's just got more power you can weld thicker metal if all you're doing is like say you got a muffler shop and all you're doing is welding exhaust pipe and mufflers you know actually a small welder might be fine might be as good as or better than a big big welder one thing I do like about small mig welders is small make gun so if you're doing like you know muffler work all day long it would be important to you to have a nice small gun that was lightweight to reach up and be able to maneuver very easily in tight spots for instance compare these two guns you know this is the tweak o gun it comes with a fabricator it's a higher amperage gun it's really pretty big especially compared to this gun that comes with a little Hobart 210 MVP so you know one of them's feels a lot heavier and bulkier one of them feels tiny and maneuverable what about pulling versus pushing pushing versus pulling here we go you know that's an age-old argument there is not a right or wrong way they're just a little different you know we all know that there's sometimes you get in a position then there is no option you can only do one or the other and basically it's it's kind of like just know just know that they're a little different you know one's not like awesome and the other one is bad it's just that you're going to get a little different bead profile a little bit different penetration and you know sometimes a little more or less spatter so I've done lots of testing on pushing and pulling as long as you stay on the front of the puddle and keep that stick out short both of them can work so I'm not gonna get into that deeply let's take a look at some of the testing that I did though this was just dumb strictly on lap joints using a little technique that tries to stay up in the front of the puddle with the arc pulling and pushing same settings same exact settings no preheat on either either joint and then I cut them using a band saw and then sanded them using around 120 grit flap disk and then used a little bit of stainless steel discoloration remover heat tent remover to swab edge and width to reveal the weld nugget you can also use naval jelly rust remover and works pretty good for doing that too and it's safer but you can see there's just not a huge difference in the penetration or the bead profiles on any of these welds well that about wraps it up for this part 2 but we're just getting started we've got a lot to cover here you know I'm gonna get out that thermal arc fabricator pretty soon we're going to look at some of the settings that it offers like inductance burn back some things like that we're gonna weld some really thin stuff tips for overhead lots of stuff so hey don't forget to hit that thumbs up button if you like what you see here or hit the subscribe button if you haven't done that yet and we'll see you next time

Channel: weldingtipsandtricks

Views: 1,718,711

Rating: 4.9589095 out of 5

Keywords: mig welding, Gas Metal Arc Welding, mig welding basics, mig welding fundamentals, welding, mig welding tips, mig welding course, mig welding lesson, mig welding for beginners

Id: AZbCTg8otRc

Length: 17min 1sec (1021 seconds)

Published: Tue Aug 05 2014