Flux Core MIG Welding Explained: Setup & Wire Loading Guide

Added: 2026-05-30

[00:00:01]Today, by popular demand, I'm going to talk about welding.

[00:00:05]Stick around.

[00:00:11]So, what is welding? Well, welding is the process by which we join metal together. So, we could take two pieces like this, heat up this edge so much that it turns into a liquid. Then, when it solidifies, those two pieces will have become one.

[00:00:28]The simplest form of this is the spot weld. So you've got a piece of metal here and you've got this overlap coming around the top. So if I then take my spot welder with an anode and a cathode and run a very high power electric through it, clamp it on the back and the front, send the electric current through it so that it melts the metal, take it off, and when the metal solidifies, it has welded it together.

[00:00:58]When we look at the top of the spot well, you can see that it's it's sunken in. And that's because that molten metal now takes up less space than those two pieces of solid metal did before. On your spot weld, your anode and your cathode, your positive and negative are like this.

[00:01:18]On your MIG welder, your positive and your negative are like this. So, we're going to weld two pieces of metal together like this. We're going to melt this one and we're going to melt this one.

[00:01:31]When it solidifies, they'll join together. But, as you saw with the spot weld, there's a shrinkage. So, you could get a situation where this join here is actually thinner than the metal that you're welding together. So, what we do with that is we have to add more metal into that join. So the whole three of them are melting and that's where this comes in.

[00:01:58]And so that's the business end. This clamp here completes the circuit. And the gun does two jobs. It supplies enough electrical power to heat up and melt that metal. And it also supplies a feed of extra metal to make up for the shrinkage. So MIG welding basically is all about the balance between how much electricity is coming out of this, how hot is it, and the speed that that wire is fed out. How much do you need to add to the weld you're doing? And that's all controlled from here.

[00:02:38]So this knob here controls the speed that the wire comes out. And then these switches here, this is pretty basic system. They control the heat. I've got minimum one and two and I've got maximum one and two. And it's all about finding that balance between those two things, the heat and the feed.

[00:03:01]All right, so that's the theory.

[00:03:04]Let's get into some practical.

[00:03:07]What's inside here?

[00:03:10]But wait, disconnect the battery.

[00:03:16]And that goes. If you're welding any sort of electrical equipment, switch it off, unplug it. You don't want two sources of electricity going through it.

[00:03:27]All right, let's have a look in here.

[00:03:29]Let's be super safe. Unplug it from the wall.

[00:03:36]First thing we're going to look at here is these connections. You can see there's a plus and a minus. You can swap these over. If you're using flux cord wire, then the negative needs to go to the gun and the positive goes to the clamp.

[00:03:57]And that's how this is done here. Just follow the wires from there. If you're using norm uh gas system, these swap round. So when you get your new spool of wire, this is how it comes. This one's encased in plastic. You've got a paper cover around there. And then somewhere you'll find a hole in it and the end of the wire is threaded through there. My wire is already in here, but what I'm going to do in a minute is I'm going to take that out. So, I can go through the process of fitting it in.

[00:04:32]Uh, you can tell this is flux cord wire because it says flux cord wire on it.

[00:04:37]And this is just mild steel wire. And it doesn't say anywhere on it that it's flux cord. So, what you've got to do with this, when you unwrap that, you need to keep hold of it because as soon as you release that, cut that little wire that goes through the hole, this whole coil wants to go bo and spring off and turn into a bird's nest. So, you want to make sure that you're ready to rumble before you actually unwrap this and put it on. So you've got to get everything clear in there. So I'll just undo this. Now this is the tensioning clamp here. You have to unwind it a bit and drop it down. Once you drop that down, it acts on that. So there's a little wheel there and there's another wheel there. That wire is coming through and going over onto that wheel. That wheel turns and sends it down the tube to the end of the gun.

[00:05:36]So, I'm winding this wire back in now, and I'm filming it just so you can have a laugh if I let go of it, and it turns into a massive bird's nest.

[00:05:50]There it comes.

[00:05:52]Now, this nut here, this is spring loaded.

[00:05:58]There's a spring in there. You don't wind that up tight all the way. You just use that spring to get your tension so that it it'll either be loose or it'll tighten up and it won't turn at all. And you've got to find the right tension on that, which will do that when I put it back on.

[00:06:17]So, I'll just show you this. Now, if I just loosen the tension, watch that bit of wire there. It just it wants to dive off. So, what I'm going to do now is find a hole.

[00:06:29]There's one.

[00:06:32]Shove this through and pull it back like that. And that's it. It's safe now. It's not going to bounce off. I'll just take this off just to show you. That's the little wheel that drives the wire.

[00:07:00]That will pop off.

[00:07:02]No, it won't.

[00:07:06]Well, it doesn't want to pop off, so I'm not going to force it. You can see there's two grooves in it. Uh, a thicker one and a thinner one. And it's actually written on the side there what size of wire goes in which. And the what you're looking at now is giving you the size for the wire that it's being that's going through. We're in the thicker one.

[00:07:24]And also with flux cord, they're usually nurled. They're serrated, those little grooves, so that it doesn't crush it.

[00:07:34]Right. So, we'll put the spool back in.

[00:07:38]Leave that threaded through whilst you do this.

[00:07:43]That back on.

[00:07:46]There is a There you go.

[00:07:49]Put your spring and your nut.

[00:07:56]Now, when you put this on, you want that wire to be going in the straightest line towards that tube where it's going to go in. You don't want it here trying to go around that corner that way.

[00:08:08]So, you can just spin this now. And what you want this to do is not be tight. If you wind that all the way, it'll stop it all together, but you just want it so that it's got a little bit of resistance on it, but not so loose that the wire comes upwards.

[00:08:25]Next, I'm just going to snip that wire.

[00:08:30]Get that out of the way. And then thread it through the tube.

[00:08:36]And again, you don't want any kinks in the end of this wire. It wants to be nice and straight. We just keep feed that through until we get to there. And now this is a little tinker to get this. You always need a tiny screwdriver to just lift that wire up to point it into that hole.

[00:09:03]Right. So that's that in.

[00:09:07]Now close this off. Put that down. I push that back up.

[00:09:13]Put that back up to there. Give it a couple of turns. Nothing too drastic.

[00:09:18]All right. So, I've plugged it in.

[00:09:21]Turned it on.

[00:09:24]What I'm going to do now, get this cable in a nice straight line cuz that wire's got to make its way down there. Then just press it and it feeds. Speed the feed up. feed up a bit.

[00:09:42]That all seems to be working. Okay, the next thing I've got to do is remove the tip from here.

[00:09:50]So, this shroud here, well, on posh ones that screws off. On this one, it doesn't. It just pushes on and off and it falls off every now and then. And then inside you have a tip.

[00:10:05]So, that should just be that tight.

[00:10:08]And after that should unthread. There it does.

[00:10:15]That one looks like that.

[00:10:20]That's what they look like when they're new. Now, these tips all come in different sizes.

[00:10:25]And you match them to the thickness of your wire. Now, I've got 8 mil in here.

[00:10:33]And so, I'd have to find a tip that's eight. There you go. I've got8s. Now, you obviously you can't go smaller, but you can go a little bit bigger if you have to, but it's best to try and match it to exactly what the wire is.

[00:10:49]They start off life looking like that, but they do wear down with time, but they're only about a pound for five.

[00:10:56]They're just a replaceable item. That one's not completely added yet. I'll keep it for emergencies, but I might as well put a new one in.

[00:11:04]Now, to know what kind of tension you should have on the wire coming out on that little knob on the top, you should be able to just about stop. You should be able to just stop it. So, that I'm stopping that too easily. So, I'm just going to tighten that a little bit.

[00:11:20]That's it. Two more.

[00:11:23]That's it. I'm finding it quite hard to stop that now. So, that's your tension there. Next thing, get your tip. Slide that one on.

[00:11:41]These tips have also have got the measurement is actually printed onto them.

[00:11:48]And then just knit that up. No need to do anything drastic to it.

[00:11:56]Put your shroud on.

[00:12:00]The reason that you want to keep this hose straight coming out of that machine is because of the liner that's inside here that the wire has to thread through.

[00:12:12]And that's that liner is constructed exactly the same as this. It's of wound sprung steel. So if you've got a kink in it and that wire is trying to go through here, it's going to get stuck in these little ridges. So, if you keep it straight, it'll be able to go through and it won't jam.

[00:12:34]So, there you have it. You just got one l last thing to do, and that's to trim this wire. So, you want a pair of something like this that cuts easily, and whilst you're welding, you'll keep them with you at all times.

[00:12:47]Because when you start to weld, you just want a little bit sticking out the end like that. Sometimes it'll go wrong and you'll blow through a hole and you'll end up with a big piece sticking out and you'll just want to snip it off again.

[00:13:00]So that's one of your tools of your trade for this job.

[00:13:04]I bought this machine about 10 years ago. I don't think you can get this model now. I had a look on machine this morning and I couldn't find it there. So it must have been modernized. I'm sure things have come along because in fact when I had this as a flux core machine some people hadn't even heard of it at that time. The reason I bought this one is because it was the most powerful one that you could use off your main socket just by plugging it into the wall without having to go threephase or anything. It does 130 amps which meant that it could weld up to about 5 mil I think. And I have welded some pretty thick stuff with it. I've also welded some pretty thin stuff as well, but I like this one as well because it could later on you could convert it into a gas one. And I've actually bought all the bits to convert it into a gas one, but uh I've never got round to doing that.

[00:13:59]And knowing now what I do, uh I wouldn't bother getting one to convert. I most certainly wouldn't pay any extra money to have one that you can convert because quite honestly this is so handy to have this. You can take it outside and weld in a force 9 gale. That's the difference between the gas and the flux core is one of the differences anyway is that this you can use outside in the wind where you would struggle with the gas system.

[00:14:29]We're now set up to weld flux core. And one of the scariest things I found about this when I first got it was if there's that much electricity going through it to melt metal, it's going to try and blow me up at its earliest opportunity. But it's actually quite hard to electrocute yourself with this thing. As you saw me press the trigger and hold on to this. You have to be careful that you don't actually join yourself in between that one and that one. That will give you a shock. And then the other one is very obvious is water. Don't use it in the bath. Don't use it in a swimming pool. But they're very rare occurrences where maybe you're sweating or it's raining and then you can get a shock from it. So keep everything dry. If you're the kind of person that thinks that you're going to not be happy until you can make perfect welds like this or this, all them little swirly patterns that you see. Now, I wouldn't say it's impossible, but I'd say it's unlikely you're ever going to achieve that kind of perfection with this. It's a wrong tool for the job. If you want to create fantastic, beautiful, neat welds like that, you've got to go for the gas. Now, that there's thousands of welding videos on YouTube, and I honestly I've watched most of them, but when you see fellas getting fantastic welds with this, they're using very thick metal in perfect conditions, and we quite honestly are never getting that. We've got rusty metal against new metal. We're going upwards. We're going across. We're coming from underneath.

[00:16:12]Trying to get welds like this on what we're doing here. You're absolutely wasting your time. The name of the game here is to make strong welds. The grinder will sort out the neatness.

[00:16:24]And so, what's the well-dressed welder wearing this season? Well, here you can see Rusty in a nice pigkin penny. This is dead handy if you're doing a load of work stood at the bench or whatever. Leather shoes are better than plastic ones.

[00:16:43]And what if you have to go underneath and do some upside down welding? Well, this genuine pigkin straight jacket is just the job. This particular version has got the genuine distressed weld spatter finish to it. Very stylish. And of course, no accessorization is complete without a hat and gloves. Red's very invogue this season. And of course, here I am wearing the new electronic super fascinator. And then, of course, if you're going to invite some friends around, you can give them these so they can watch the show. There's another version for friends with long faces.

[00:17:27]This is my original helmet. Uh, and it was an Elchipo one at the time that was 40 quid. It doesn't switch on or off, but it does have a setting here for the brightness on the lens. It's got a solar panel here so that when you're welding, it's charging up and it takes a couple of uh aoublea batteries. Now, I was quite happy with this for a long time uh until I started to need very focals and then I found it difficult to see out of and I realized that these lenses were all a bit scratched and so I needed to get some new ones of those. So, I started trying to find them. I didn't really have much success. But what I did find was a brand new helmet for a tenner on eBay. And this one has got an onoff switch as well as the brightness adjustment.

[00:18:28]And then when you come inside and have a look, you've got a delay time and the sensitivity. So that's how quickly it flashes on or off. And then the delay time is after you finished your weld. If you have been welding very hot, if the uh if it goes back to clear too quickly, you're going to get dazzled by it. So, you can change that end delay time after the light has gone out before it then becomes clear again. So, that's another feature as well. And that has been a really good helmet for 10 quid. And I'm still using that. Now, upgrading.

[00:19:10]Well, you can pay an absolute fortune for these. The technology is in here in this little lens bit. And you can buy these with all flames and all kinds of stuff on them, and you'll be paying for the flames and the stuff that's on them.

[00:19:25]I'm not really getting any better technology in there. Now, I'm happy with that for a tenner. So, what I would suggest you do if you're just getting started at welding, get one of these.

[00:19:36]And then later on when you know more, you meet more people and they can recommend a really good helmet for you to go and pay hundreds for, then that's when I'd do it. But I wouldn't go buying one of these blind and paying a lot of money for it. Not worth it. Now, the next upgrade I'm going to make on this because I'm a very focals, they get more expensive as this screen actually gets bigger. And so that's where I'll be going next to get that bigger screen.

[00:20:06]But whilst this one's working, I'm just too tight. I'll I'll have to put it on my Christmas list and maybe the family can buy it for me. So another difference between the flux core and the gas is that this flux core burns a lot hotter and it's a lot brighter. So it's actually harder to see what you're doing with your welding.

[00:20:30]And that's really that's another reason why you it's so much harder to get these beautiful intricate little weld patterns because you can't just can't see it as well as you can with the gas stuff. Now, believe it or not, and it's counterintuitive, but one way to improve what you can see is to actually shine more light onto what you're doing. Get some lamps in there and get it really bright. And another thing you can do is the position that you're going to weld in on that line of the join between the two metals. Get a piece of chalk or something like that and actually draw down that join so that when you're in there and it's all dark and it's all going on, you can see that line if you're struggling.

[00:21:14]Right. Well, I think that's enough to take in for uh one day. Um, I've been a bit slow getting this video out because I did my backing at the beginning of the week. I had a week off and I intended to get loads done. Uh, it's partly why I decided to do this video because it wasn't too strenuous. For the next one, I'm going to be getting into these footwells and this bulkhead up here, repairing all this. And whilst I do that, this time I won't just do it. I'll actually go through the welding process with you. I'll show you what tools I'm using for the preparation and uh we'll have some fun doing that. I've got some thanks to give out. Okie Rover sent me this fantastic tie. This is the Oklahoma State colors. It's very fine quality and it's got the Oklahoma emblem on there. Thank you very much for that.

[00:22:08]And then I've got some super thanks. A super thanks for Irvan G, Tristan Barber, and S doublecross DR. Super thanks back to you. Some of you will have recognized the See You Around and the uh music at the beginning. That's for Fitzy's Fabrications.

[00:22:28]Go and have a look at him. He's absolutely brilliant at doing welding jobs and making crazy bits of metal. And he's got a a new playlist out this Ford Vic F100.

[00:22:40]Now, also, I've got a correction to make on the last video. When I took the shackle bolts out, I kind of held them up to the camera and said, "These nuts go in this way, and it was actually a reminder to myself for when I put them back. I could go back to the video and put them back the same way they came out." But I've been corrected. The nuts on the shackle bolts should be on the inside. That's how they're shown in the book. And I suppose it kind of makes sense because they're getting less uh road rash on the inside here than they have up against the wheels. This one might be worth a look. A young fella and his dad have been doing up a Land Rover over the winter. I've been watching them and they've just finished doing that.

[00:23:25]Now, if you look just there, there's a white dove. And that white dove has made a nest up there. Where's me hand? Up there on top of a radi an old radiator that's lying down. And the chicks have hatched.

[00:23:41]I've got a bit of footage of that I might put on later. Hypes on the last video. What a sterling effort. I think it was 247,000 points which put the video in at number eight in the DIY field. I don't know why it's in the DIY field. They don't have a motor vehicles thing. But, uh, well done everyone. Thanks very much for that.

[00:24:03]Especially those of you who did all three of your weekly hypes on it. Thanks for the support.

[00:24:10]Here's another one. He's just started a Land Rover series 2 restoration. And funnily enough, he was doing the rec rear crossmember at the same time as I was.

[00:24:20]Now, I've been busy on the channel doing a bit of housekeeping and I've put chapters into all the videos. Well, I'm making I'm not quite there yet, but I'm making my way through all the videos.

[00:24:31]So, we'll have chapters in. So, if there's something comes up in the future and you go, "Oh, Rusty did something with that." and I think it was in this video. You'll actually be able to flick through it and at the bottom down here, you'll see as the red line goes along, it'll come up and it'll tell you what part within the video that sort of thing is. So, there's one to help you out. Um, I had a complaint about adverts and well, adverts, I do earn a couple of quid from that. Honestly, it's not much.

[00:25:01]It's about 50 quid a video. It doesn't scratch the sides. So with that in mind, what I decided to do was I went to the video and I have an option where I can knock out half of them. So I went back to that video in particular and I knocked out half of the adverts. Uh and I'll be continuing to do that. I'm not having uh them spoiling the entertainment just for the sake of a few pennies. So I hope you all enjoy that.

[00:25:28]And here's a young fella having a go. I like to support the youngsters. He might be a bit Gen Z for some of you, but have a look for his video on the history of the Land Rover. I learned a couple of things from that.

[00:25:41]So, if you're watching this video in the future and you've lasted this long right to the end um as soon as I put out that next video, I will add it as an end screen to the end of this video. And all you'll have to do is wait for the end and then click on that and it'll take you straight into part two of this where I actually start doing some welding and show you how I do that. But for now, thanks for watching. The usual like, subscribe, hype, and if you do go visiting some of the sites that I've put on for you to go and have a look at, just let them know Rusty sent you.

[00:26:17]Thanks for watching.