Everything You Need To Know About Welding | How To MIG | Workshop Diaries | Edd China

hi welcome to the workshop today we're going to tackle a subject I get asked about all the time MIG welding [Music] humans have been sticking metal together for thousands of years in fact about 5 000 years when Egyptians invented braising now brazing is a particularly useful form of fabrication because you can use all kinds of different types of heat sort in the first place to generate the heat but also you can actually stick dissimilar Metals together and you can do everything from really fine gas pipe work and jewelry up to much more substantial things like big bronze sculptures for example now the only disadvantage really with braising is it's not as strong as welding that's because you're bonding two bits of metal together with a third softer metal at about 450 degrees Celsius and that's actually what's holding the whole thing together rather like a really hot glue gun whereas with welding you're actually heating up the two bits of metal so much that the edges melt together in a shared pool of molten metal and once that cools or sets then you end up with a really really strong joint because those two parts have now become one and you can sometimes use a filler metal rod or welding wire to actually better get the heat right into the world and make a nice homogeneous mix of of that molten metal and once that's set you get an even stronger weld with gas welding you have a fuel gas mixed with either air or oxygen to make a flame so hot that it actually melts the metal but steel has a melting point of 1500 degrees Celsius so it's only the gas combination of acetylene and oxygen which burns at 3 500 degrees Celsius is actually hot enough to melt or liquefy the steel then we have arc welding which uses the intense heat of an arc of electricity to melt the metal and because the arc reaches temperatures of 19 000 degrees Celsius then that melting of the metal happens very quickly which means it takes much less time to form the Weld and that means much less heat is put into the job so it helps to minimize the Distortion and damage to your metal which is great but with arc welding the metal can get so hot but it can start to react with the oxygen in the atmosphere it can boil and burn and that's why you need a protective shield around the world to stop the oxygen getting to it before the steel has cooled with MMA or stick welding that shielding is actually created by using a flux whereas with TIG or Mig gas welding then that protection actually comes from a little tiny protective bubble of inert gas which is actually fed through the nozzle of your torch so in the early days of Arc world and you'd have had just a stick MMA which is manual metal arc welding and then the idea of the stick means you could obviously use that to feed into the two bits of metal you're trying to stick together and of course that would melt down and then give you your weld now there are a number of advantages with MMA welding for one thing you don't need any protective gas around it so you can actually do it in a Blustery Day in the middle of nowhere in fact you can even weld underwater that's how they stick oil rigs together the disadvantage is you end up with this kind of oxidized layer the slag that goes on the top of the world and that needs to be cleaned off before the job is finished it can be a bit of a faff now in the middle of the last century around 1949 some bright Sparks invented TIG and MIG welding tungsten inert gas and metal inert gas now TIG and Mig use exactly the same technology they use electricity to generate a nice hot Arc and a little bubble of inert gas to protect the molten metal that that hot Arc is creating to stop it from oxidizing from the air now the thing is the main difference is in the T the T stands for Tungsten and that is referring to the little metal rods you use to kind of cajole your pool of liquid metal along the world as you go with TIG welding far less of that little tungsten Rod is actually consumed during the world compared to the huge amount of wire that's going to be fed into the world with Mig so the finished result is nice and flat and doesn't require any grinding down now often asked what would you prefer TIG or Mig well it really depends on the application in the case of our Giant shopping trolley here most of the shopping basket itself was actually mixed together because all these parts had huge gaps between them which needed to be bridged when it came to the base you can see this lovely welding down here was all done with TIG and that's because these parts that were being welded together were accurately cut so there were no gaps and that's really the problem there is nowhere to hide with TIG if you haven't done your work or your Prep properly you haven't cleaned it properly you haven't cut all your pieces properly then of course it's very difficult to fill those gaps but also if you make a mistake everybody can see on the flip side the world is also going to see if you do a fantastic job which is why it's often used for sticking together things like stainless steel exhaust systems perhaps manifolds on racing cars even the tubular chassis on racing cars motorbike frames all that kind of stuff where it just looks gorgeous if it's done right essentially TIG welding is for precision work when you've got a steady hand but if your repairs are a bit Rough and Ready and you need to do a bit of improvisation and that's where MIG welding really comes into its own because it's just so forgiving so if your patch repairs aren't quite so accurately cut you can fill in the gaps if you've got little pinholes to sort out you can fill those in too and if you mess it all up you can grind it back and start all over again so if you're just beginning to learn how to weld then MIG welding is the thing for you to try so today we're going to talk about MIG welding now as the name suggests metal inert gas there's some metal in the form of a wire which is actually on a coil which is constantly fed through the torch of the welder then the inverter inside the machine in this case actually converts your Mains electricity to a lower voltage but a much higher current and that current is what provides the energy to actually melt the wire that's being fed through the torch and of course that intense heat that energy is also going to cause sort of heating of the metal you're going to be welding and then that's going to cause a nice weld pool and a little extra bit of metal you're putting in is all going to kind of mix up and make a lovely strong weld now early migrados like my old one here used bulky Transformers to generate the arc which is why they were so big and heavy you can also see you've got all these switches on the front for a relatively coarse adjustment of the currents but also a manual adjustment of the wire speed thankfully advancements in technology now mean that the Transformers have been replaced with inverters and some Electronics which means the welders can be much lighter and smaller in fact these two are exactly the same power 200 amps but clearly this new one is actually a quarter of the size but more significantly on this synergic world of the electronics make those adjustments much more precise but also some of them are automated so they're adjusted constantly as you weld to optimize that world now you can imagine that the energy coming out of the Ark is pretty intense in fact it's probably about half as much energy as you'd get from the Sun but the sun is 93 million miles away whereas this world is right here in your face so obviously you do need to protect yourself and just like the sun you end up with infrared which obviously is warming you up you'll end up with also ultraviolet light and you get a B and C but on planet Earth thankfully we still have enough atmosphere to actually block out both B and C most of the time so most of the stuff we get is UVA but unfortunately B and C are very very dangerous they can cause skin cancers they can do all kinds of damage to your eyes so you really do need to protect yourself from all of that as well but also again bear in mind that heat is melting Steels in it with molten metal and that molten metal can be flying all over the place and believe me you do not want a big glob of liquid metal pouring into your ear or into your boot and then running around your toes it is very uncomfortable so first up we're going to need a mask now when I bought my very first Mig world or it came with this kind of weird folded cardboard shield with a little tiny tinted window in there that was apparently the right amount of tint to have that UV protection had a little hand on the back you'd hold that and then weld away but it's quite difficult working with only one hand to do your welding or especially if you had to hold the metal together which you shouldn't be doing obviously use magnets it's so much easier a bit later in my world in career I got my hands on a welding helmet now that was great because then I had my hands free which is very very handy but also you did end up tending to kind of weld up and down and up and down with the helmet as you're trying to look at your job and then obviously protect your eyes and sometimes you get out of sync but then thankfully somebody invented these solar powered welding helmet and so you have a little solar cell here and that generates the energy to power some LCD shading which then happens automatically the moment you strike up the arc so then you can actually protect your eyes all the time you're working and of course when you're welding stops you can still see how you'd got on which is great so that's your eyes protected but next we need to think about all those noxious gases that are coming off your welding and going into your lungs so at the very least you're going to have to be using one of these it's an ffp3 standard mask and that's going to make sure that your lungs are nice and protected but actually thankfully just like welders these days PP has also had some technological advances and you can now get an air fed mask which is also solar powered and you can see there's a little umbilical cord here actually gets fresh filtered air pumped in from a little pack on your back so now you've got a nice solar-powered eye protection you've got nice clean air coming into your mask and you've got free hands it's the next thing you need to worry about is actually protecting those hands now this is where the technology really hasn't changed over the years what you need is a nice sturdy pair of leather gloves now you can have two different things just depending on what kind of welding you're doing so if you're doing kind of precise TIG welding then you can get away with slightly thinner kind of more dexterous leather gloves but if you're doing MIG welding particularly if you've got your hand right by the arc for long periods of time then you want something a bit more substantial just to keep that heat away from you and also bear in mind that when you're TIG welding the actual work itself won't be taking on quite so much heat so it's going to be cooler to the touch slightly but whereas with MIG welding you are going to be putting a fair chunk of energy into your metal so this also protects you not just from the welding but also from touching your work so we've protected our eyes we've protected our hands the next thing we need to worry about is the rest of our bodies now just like the sun your clothes will protect you from a certain amount of UV and infrared light but of course they are still flammable and you have all this is molten metal flying around all over the place you're going to need some proper protection now if it's a little job then you can probably get away with a nice leather apron but if you're going to get really stuck in then you want some all-round protection and it's very very stylish particularly if you're still living in the 70s thankfully the 21st century has some advancements here too you can now get heat reflective and fire resistant material which is nice and light and comfortable to wear in almost any color well now we're nice and protected I can finally talk about MIG welding as I mentioned earlier Mig stands for metal inert gas so we have our big bottle of inert gas here and the metal is on this reel here so it's a 15 kilogram reel in this case of Steel at 0.8 millimeters in diameter now what happens you've got these little rollers Little Motors down here so when you push the trigger on the gun so the wire comes off the Reel again through this little Motors through these rollers and they drive that wire all the way down through the lead scanner actually comes all the way up to the gun so when you push the button the wire then comes out at the end of the torch so when this little wire here actually touches your metal it's short circuits and that Rush of electrons produces a whole load of heat in fact you get a big blue Flash and that blue flash is just like when a fuse blows essentially it's converting that solid steel heating up and turning into liquid molten steel but at the same time it's also heating up the metal you're trying to weld so this bit of molten steel drops in and dilutes in the pool of molten Steel on the work you're trying to weld together and eventually when it freezes it becomes a nice hard join which of course is what makes welding so strong now perhaps one of the most common questions I get asked about welding is what wire diameter should I be using with my welding well it all comes down to the thickness of the material that you're hoping to stick together so just like any other conductor the thicker the conductor the more current it can actually handle before it starts to melt and in the case of welding normally you have 0.6 0.8 one millimeter and 1.2 millimeter thicknesses to choose from so 0.6 millimeter wire normally really good for really thin sheet material so 0.5 millimeters of Steel up to maybe 1.3 and then for 0.8 y you'd go from 1.3 to 4 millimeters and you could go right up with the 1.2 millimeter wire to 20 millimeter thick plate which is pretty full on even thicker than on the mezzanine so the thinner the material the thinner the wine obviously the other way the thicker the material the thicker The Wire so to answer the question I tend to go for 0.8 millimeter wide just because I don't generally do that much really thin body work just slightly thicker stuff but I'm also quite partial to building measurements if you're anything like me you'd be curious as to what would happen if you use the wrong size wire So to that end I thought we'd do an experiment I've got myself some very very thin sheet metal 0.8 of a millimeter so it's too thin for 0.8 wire but actually ideal for 0.6 wire and at the other end of the scale I've got some thick plate 10 millimeters now this of course is ideal for one millimeter wire but way too thick again 4.8 wire and then we've got our Goldilocks steel here which is 2.5 millimeters thick which would be what I'll be using to repair our chassis and of course that's its spot on in the middle of the 0.8 wires range that's going to be ideal now because our gys welder is synergic that means you give it some basic information and it works out the rest so essentially you tell it the diameter of the wire the thickness of the material and how you're going to be welding and then it works out the wire speed and the current that you need to actually make a really lovely weld [Music] foreign [Music] let's have a look at our results so this is the Goldilocks world so this is the one that should be ideal so we've got basically 0.8 wire with our two and a half millimeter sheet material and you can see that actually the world looks nice and consistent if you look at the heat discoloration on the steel you can see it's actually even on both bits of metal and for every side of the world which is good sign you can see on the back we've got a little bit of penetration going through so definitely the world has made it all the way through the metal so now it's all one piece so that's great so that's how it kind of should be if we now have a look at the very first test if you like this is on the very thin material but still with the 0.8 wire diameter now obviously it slightly compromised this experiment because the world has really given me a helping hand trying to improve all my issues if you like so you can see it looks like a terrible world because it is a terrible World in fact it will be very much weaker than it really should be and really it's just down to the fact that there's too much material coming into the wire just making a very inconsistent Arc and therefore a very inconsistent stick at the end of your job so we need to get rid of that now interestingly if you look at the other end of the extreme the 10 millimeter material bear in mind of course the world it could only go up to six millimeter thick normally because of its 200 amp capacity on the face of it it doesn't look like a terrible World it looks like it might hold it all together but on close to inspection first of all you can see that there's almost no heat discoloration on that edge you've got a little tiny tiny bit just there pretty much impossible to see on the vertical surface so it just means that the heat hasn't got into the job it hasn't had that heat penetration but also as the arc has been trying to pull or sort of melt the material and of course then our wire has been added to that there's just not enough material in the wire to actually make a really nice fillet to make everything flow nicely to the edges now it's even more revealing just how bad this world is when you look at the very end you can see that in fact there is no penetration into these two parts I'm trying to stick together so effectively it's only this inadequate sort of superficial fillet from the weld or from the metal that's actually coming from The Wire that's actually sticking these things together at all these are not basically one piece they're effectively two but it's sort of stuck together almost like with a bit of silicon sealant so this kind of joint is particularly dangerous because it looks kind of okay but actually I won't have any structural Integrity so it won't be up to spec so you need the right amount of current and you definitely need the right size wire for the material you're trying to stick together right now that sorted the next thing we need to talk about is gas welding gas can get a little bit confusing now when it comes to gas welding you obviously have a fuel gas like propane or acetylene combined with oxygen to actually make the heat that you can then weld with whereas in arc welding use electricity to make your Arc but then you use the gas to Shield that Arc and the molten steel from oxygen in the atmosphere to stop it burning but it's not even as simple as that because the shield gas changes depending on your application so with TIG welding for example you would always use a hundred percent argon whereas with MIG welding you would use some kind of mix so you can get light Universal and heavy so light would be argon with just five percent of CO2 this one universal actually uses 12 CO2 and then heavy would be 20 of CO2 and the idea is that the more CO2 the more reactive the world becomes therefore the more penetration you can end up with which is obviously what you want when it comes to welding but again if you use the Heavy Gas on a light job of course you're going to get too much penetration if you use the light gas on a heavy job again it goes the other way so it is important to use the right gas for your job as well now generally in the workshop working on cars a light gas would be the way forward so only five percent of CO2 but the caveat to that is when you're working on something like the chassis here which has got a bit of surface rust on it still and obviously Rusty bits inside then it might help to have a bit more penetration because it helps clear away through all of those sort of scales and bits of rust and bits and pieces and so therefore the universal gas might be a better option now just so you can see the difference this job I did with five percent CO2 this one is with 12 percent now on the five percent you can see there's a lot less World spatter but actually the wells themselves are slightly prouder whereas on the 12 you can see there's more spatter because the CO2 is being more reactive but also the worlds are slightly flatter because they're kind of digging in or getting more penetration into that metal so now I'm sure you could get a good weld with both gases but at least this way you can see what the difference is then once you've decided on your gas the next thing to do is choose the right amount now when you buy your gas you'll get it in a number of different forms it could come in a full size bottle like this half size bottle or even little tiny disposable bottle but either way they cram as much in there as they can so this bottle is at 230 bars that's 230 atmospheres of pressure inside this bottle and of course you can see how much you've got left with this little dial here that sits on the regulator and sometimes The Regulators will have two dials the second dial there is for the amount of flow that you're going to be getting once you adjust it with this little knob here now the idea of course is that you want to use just the right amount of gas to have a shield around your work now if you're working outside it's a bit blustery then of course you might have to crank that up a little bit but actually if you have too much gas it can affect the weld so what we're going to do now is just going to crank this up so it goes up to 40. there's way too much there we go and then let's just see what happens right so next up I'm just going to actually turn the gas off and then just run that down and then see what happens then right well let's have a look at our results as you might expect the welding without gas is a total disaster you can see that basically the oxygen has got to that liquid steel and it's just basically set fire to it so it's been oxidizing it's been burning you can see the world itself is much much darker and it's very full of sort of bits where they're called inclusions there's bits of all kinds of stuff in there there's holes there's bits of slag bits of burnt steel it's not looking good and the best thing is it's not going to do any actual sticking together either so it's going to be a very weak weld now the other end was where I did the world with too much gas now on the face of it looks like a perfectly good weld but if you compare it to our little bit of work we did earlier you can see now that the color is a little bit darker so you can see that it's affected the chemistry of the world now obviously if I was to really crank up the gas it end up with a lot of turbulence that could bring in the air bring in the oxygen and you end up with a very similar weld to the other end when there's no gas at all so I hadn't quite got that far but you can see the discoloration definitely lets me know I'm using too much gas now probably the most obvious thing about that is you're just going to be spending twice as much money on the gas you're using for your welding so why would you do that so there's actually a clever way of making sure you've got just the right amount you can use a pea shooter now as the name sort of suggests it's just a p or a ball sat in a tube and that tube is fed from one end via this sort of rubber gasket by your gun and then it just vents to wear on the other side so the idea is you get your welding torch pop it on there and then of course when you pull the trigger you can actually see the ball the P move the amount of air because what you don't want is the wire to be coming out at the same time so very simply you just disconnect the clamp in this case and that way the world is still going to try and spin the motors but of course it's not going to feed the wire through the torch I'm just going to pop my peashooter onto my torch it should actually stay in place you can see the P almost fires straight out because of course I'm still on my huge amount of volume from before my flow so now I've got a little bit low so I'm just going to go back up to about 18 see the world is composite I've got nothing going on right there so I've got about 18 liters per minute if I now look at the dial you can see it's showing a little bit less and obviously that's because there are going to be discrepancies there's going to be losses between here and going all the way through the world all the way through the lead up to my torch which is why it's important to check it with the peashooter then just rely on the gauge here right then we've got the right wire we've got the right gas and we've now got the right amount of gas flow so the next thing we need to worry about is how to hold the torch when you're doing your welder because that's also very important so a grab hold of that so you can imagine this is our job just here so first of all you have to tilt the torch to 45 degrees to the work you're working on because it's very easy when you've got a right angle fillet to do then you have to tilt the torch 15 degrees back and then most importantly with Mig you need to push not pull the welds you're going to be pushing along that way as opposed to dragging it like you would with TIG and it's all to do with the formation of the pool of molten steel but also the bubble of Shield gas around your weld right so now we know what we should be doing with the torch let's try the final thing to worry about which is the speed you should be pulling the torch along because that also has a huge effect on how your weld as you might imagine now the trick is it's obviously not going too slowly or too fast I'll show you what happens in a second really you're looking for a Sizzle if you can hear the world like kind of sizzling bacon in a frying pan that's the kind of noise we're looking for and it makes it really nice and easy to see what's going on so I'll just pop the welding mask back on foreign [Music] [Music] so let's have a look at that so you can see I started off with a pretty normal Weld and then started to go too fast you can see that bead of weld kind of gets a bit narrower for a start because I'm going too quickly but also you can see the heat just isn't getting into the job but then I start to slow down and go far too slowly end up with a much much fatter world but also the heat you can see is really being pushed into the metal it's why this sort of coloration is going all the way out almost to the edge of our metal here so again we're looking for that Goldilocks zone not too fast not too slow but just right right though I think we're all set so it's now time to put this all into practice but it's just one more thing prepping the job obviously that's also very very important so I got myself a slightly more realistically Rusty bit of Steel here now obviously that iron oxide isn't going to help your world it's going to contaminate it in fact if you're welding aluminum it's particularly difficult because an oxide layer forms within about 30 seconds of you cleaning it so you have to be really on top of that thankfully steel is a lot more forgiving but you're still going to have to clean through the rust to the shiny method the same thing would go for something like perhaps some flat that you might buy in which has been rolled so it has this kind of skin slightly darker color skin on the outside you also want to cut through that to the bright steel beneath now again here you've got a bit of a choice you could go with your standard grinding disc now anything I find with these is they're a little bit hard they kind of Bounce and skit over the work so I tend to go for a flap disc because it's much more forgiving but also you can get different grades of coarseness depending on the work you're trying to clean now if you're going for something like really really light paint to work perhaps or some light rust again you can go with this coarse cleaning fleece which is kind of like a hard sponge that's very very abrasive but it's again probably lighter work than perhaps the flap disc so [Applause] I'm just holding my little work piece down here with some magnets you can obviously use the back end of an old speaker or nowadays you can easily get hold of some nice strong neodymium magnets to do the job but one thing to bear in mind if we were TIG welding that magnetic field could actually mess with the shape of the arc and therefore you want to actually use them perhaps just to get a couple of attacks in to get some Mig tacks in and then you would remove the magnets before you do any TIG welding right I think I'm about ready to weld a chassis all right I guess that's not quite going to cut it but at least now I'm ready to start welding on our Rusty Range Rover chassis but that is a job for another day [Music]

Channel: Edd China

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Id: mKECEAT8MlE

Length: 27min 17sec (1637 seconds)

Published: Fri Nov 11 2022