Flux core welding part 5: let’s weld car exhaust

good morning YouTubers and today's episode I figured why not teach you guys how to weld car exhaust since these little Flex core wire welders work really well on thin wall pipe and that's what I figured a lot of you guys might actually use one of these for I went out and bought a couple sections of pipes so I bought a what's considered a tailpipe inch and 7 8 by 18 inch just got this from the local AutoZone and then this one which I cut up is a two inch by 18. the reason I did this because I'm all about efficient AKA cheap means of practice this pipe here Clips right over here so what it allows you to do is put a bunch of these on there and then practice your lap welds so pretty convenient it's also economical both these pipes combined I think were 10 bucks or something and I just saw these with a Sawzall just like the catalytic converter off your car so there you have it let's get into it a couple things I want to talk about here so first thing is safety this exhaust pipe just by looking at it looks like it's probably zinc coated or has some kind of anti-rust protection on it I I know Factory car exhausts are often aluminized it's called we don't really know what this coating is one of the smart things to do would be to wear a respirator while welding it you don't want to be breathing in a bunch of zinc fumes because you can get zinc fume fever and you'll be throwing up and trust me milk isn't going to save you once you get it so be smart about this I'm welding it in my shop I got a error handling unit here that's going to clean up the air anyways but be smart the second thing is there's two common joint configurations on car exhaust you have what's called a butt weld where the pipes come together just like this and then you have what would be a lap weld the lap weld is most commonly like if you want to weld a muffler into a exhaust system or if you want to splice two pipes together now pot welds are significantly harder to weld the reason is is that if you're over the amperage or your travel speed is too slow you'll pop a hole in it immediately so it's much harder to weld butt welds which if you're an inexperienced welder and you want to weld say two pipes together rather than trying to do a butt weld and keep blowing holes you may want to slip something like this over the two pieces and then weld it here and here and maybe tack it in the middle but that's really not necessary but that'll make it a lot easier to weld that exhaust in than just doing a butt weld so for material prepped I saws all these they're not going to be exactly straight I deburred the inside of it and the outside I did not buff off this coating with a grinder I would recommend if you're going to do this clean the edge of it off like a quarter inch maybe a little bit less as well as what you're welding it to like if you're doing a slip fit it will weld cleaner trust me on that the other thing is is that if you're welding on like used card exhaust that's all rusty definitely wire wheel at a minimum that rust off of the pipe it will weld better like just leaving all that rust without cleaning it at all is not going to do you any good trust me on that but yeah we got our pieces set up so we're going to do lap welds to start so what I'm going to do is slip these on here probably get one more on there maybe yeah so I got all the pipes set up for testing let's get going on that all right I got the welder fired up for 18 gauge the machines chart says three and a half or wire speed and voltage it says b and a half to C so I have that at uh b and a half and I have it at three so we'll see how that works now before we go and weld these lap joints I'm just going to use this end piece I'm going to run a couple welds on it and we're going to look at it foreign as you can see blew a hole pretty quick that might have just been me let me reposition Pride again and I am running vertical up seems just a little bit hot I'm going to turn it down a little bit foreign probably should have cleaned that sticker off I had a little bit of a push angle at the top but that seems to be a little bit more controllable we're not depositing a very big weld here so that looks a little bit better let's brush it off and see what we got foreign so this was going pretty good decent width blew a hole at the end carried too much heat same thing here lowered the settings doesn't really look that good we're gonna need to do a little bit more practice to get this set exactly right and work on my form a little bit let me clean the sticker off out of curiosity I cleaned off some of this coating on here and we're going to do a weld on a clean metal and just look at it but same settings as before even though I dropped it a little bit still having issues Let's uh drop it some more there we go we got that dialed in yeah you can definitely tell see that yellow and white powder there that's all zinc any wire wheelless so I'll bring it up so you can see this having to move pretty fast depositing a pretty small weld you can see again right here part of it was my travel speed wasn't fast enough but once I made it more than a half of an inch I blew a hole same thing down here so I'm just straight Steel no lap weld or anything no butt weld my setting I'm currently at is a and a half and two and that's pretty decent let's start uh attempting to do a lap weld now I'm going to weld this to where I'm always welding uphill and then I'm going to rotate the pipe just to make it easy for me for practice however obviously when you're welding on a car you can't rotate the pipe so in that case you got to get used to welding uphill as well as kind of at an angle on top of the pipe where you maybe don't have good visibility as well as you have to do overhead because you have to weld the bottom of it once I do a couple of these I'm actually going to set this up and weld it in position where we will together we'll weld it all the way around without rotating the pipe but for right now for practice we're going to do it in position where it's at so our first weld is done all the way around I'll wire wheel it and let's take a look what how it looks under there overall you can tell by the bead appearance except for maybe right here a little pin dot of porosity there the bead seems a little bit on the colder side I mean obviously this is pretty well sealed but I think we need to bump it up a little bit which doesn't surprise me running a single pass on uh just a single piece of pipe is going to run a lot hotter than when you're actually joining two pieces so I'm going to bump up the settings to be in about two and three quarters and we're going to run this side just like I did and we're going to look at them and compare them take a look so overall weld is much flatter a little bit wider seems to be wet out pretty good oh look at that one more pin DOTA porosity gotta get one of those of course yeah for not cleaning this material and just welding straight on it that's actually really not that bad and flex core wire is kind of designed to run on stuff like this so that's looking pretty good I think my settings are good I'm just going to slow down slightly and we're going to see how it welds so there's our most recent weld I slowed down a little bit I don't know that it really looks any better almost looks a little bit colder despite going slower not too bad well I'll finish this out on this one and then we're gonna actually weld this in position so I'll do the welding without rotating the pipe so let's take a look at that overall not bad so for a couple of these I was doing a little motion like kind of like a circle e just to see how that would react this one I just went forward pause for a second forward paused I honestly like the look of that better overall I got no porosity that I can see yeah not bad if you ever run into where you're welding like a gap on exhaust you're gonna have to circle around to get the heat to go to both pieces because if you just try and go right in the middle of the gap on thin wall like this you're just gonna blow straight through it so if I quickly bringing the arc or the wire over to the sides will help prevent the middle from blowing out yeah that's looking pretty good I think I like the settings that we're at uh so what I'm going to do is rig up something to hold this suspended and then I'm going to weld the next one in position all right so I got this set up here quite a bit above the table but it's going to be pretty tough to weld this so I'm probably going to come in opposite side here since the camera is above here and it's going to get in the way and I'll weld it up this direction this is definitely going to be a little bit of a challenge but I'll make it happen now you probably saw me welding at kind of some pretty crazy angles where I actually had a push angle going with exhaust pipe in a lot of cases there's just no way to get the gun up to where you can do a drag angle so there is some leeway especially I mean let's be honest it's exhaust I'm not building a space shuttle here so a little bit of push angle in order to get access hey if you can get a weld on it that's better than not having one there the other thing is I tend to weld uphill you can weld downhill your penetration will be more limited which actually on exhaust pipe might be a benefit because if you're blowing holes welding downhill you will have less penetration but let me wire the wheel this off and let's take a look at it all right let's take a look at what we got oh miss welded the bottom there yeah I couldn't really see what I was doing down there but let's take a look overall most of it looks pretty good it's just that bottom I screwed up I kind of just took a guess and thought I was getting it but clearly I didn't so we can do better than that or excuse me I can do better than that let's weld this where it's a little bit more visible and I'll do a lot better of a job let's see if I did any better yeah not my best work I don't know if you heard I actually poked a hole through it on the first side that I was welding I waited just a little bit and then welded through it again we're welding on exhaust here that's zinc treated you can't expect the best welds on it not too bad I'm gonna slip that other one on here I think maybe and do one more just like I did and we'll look at those and then we'll go from there foreign y so the first one I did right here overall not too bad the one with better visibility and access much better and you compare it to like sitting and just repositioning the pipe I mean it's so much easier to get a really decent bead appearance when you don't have to crawl around something now I obviously was able to weld with some visibility on the top of the pipe when you're welding this in the car you might not be able to see the top of the pipe and that's the hardest thing to do is to weld over this and actually have a welder that fuses and you don't have a hole or a pinhole or anything that's why if you do a lot of exhaust I'd highly recommend getting a flexible neck Mig gun because you can curl that around like this and get in there this little gun here is so small works great to get in for exhaust but it doesn't have a flex neck if it had a flex neck I'm telling you that's that's the best thing for car exhaust but yeah I mean roll not bad Let's uh practice some butt joints here time to do some butt joints now we just finished up on those lap welds start out with these two when you do lab welds it takes more heat to weld them than it does a butt joint a butt joint to weld these two is going to be closer to what it takes to weld just a bead on here and not blow a hole this on exhaust is going to be by far your hardest challenge which is why like mufflers and a lot of exhaust pieces are all designed to be a slip fit so you lap welded because it's so much easier I can tell you that the a proper setup is an absolute with butt welds on thin wall like this if you have a huge gap that's like this you're never going to be able to weld it it's just going to be impossible because it's just going to blow holes straight through so a tight fit up is a must in the case of this what I'm going to do is tack weld it in a couple places to hold it together and then run a bead over it oh it helped if I had the ground clamp hooked up let's hook that up here [Music] we go one of the things and I'm kind of a bad example here after every tack weld technically you should break the wire or cut it off because as you saw this starts on that were pretty rough it didn't want to start right away that would have been a lot better had I actually cleaned it or broke the wire off so I started with a new piece let me grab a brush here and just clean these tacks sore fit up if you look virtually no Gap now for this first one I'm going to weld and just rotate the pipe the second one I'm going to actually weld to that in position to demonstrate like what you would face on a car I have a feeling that I may blow a hole in an in position but let's do this one first thank you so our settings just are a little bit on the high side for this and I'm just going to keep chasing holes around we'll clean this a little bit and we're just going to take a look at it here so it started pretty good and again there's still a lot of flux here but I'm going to just end up chasing holes in that we need to turn the welder down a little bit so I'm going to go to like two and a half and just under B and we're gonna start again I'm going to start just ahead of the weld well let's see what kind of terrible we're dealing with so the beginning let's see I'll be able to tell so this was kind of like the beginning somewhere in here it was going pretty good but as soon as I was going uphill started blowing holes that definitely ugly so then I left the Gap and then I restarted so overall that's a little bit better burned a little hole there huh didn't even see that the flux was covering it not too good I did turn the machine down so one of the things we're going to try now as I weld this in position I'm gonna weld downhill on it rather than uphill let me clean this sticker off of here all right I've got that prep that sticker was a nightmare to take off I want to show you the inside of this pipe there's some reinforcement in there not the best again pretty ugly looking weld I ran into some problems here where I kept blowing holes through you can actually see the Gap in the pipe there it was being a real bastard so I ended up doing a series of like spot welds on it which sometimes you have to do that and it's the only way that you can keep it from blowing a hole in hindsight had I increased the wire feed just a little bit and kept the voltage really low all that extra wire that would have been stabbing the puddle may have actually quenched it a little bit so it's one of those things where playing with the settings can really help and doing more practice definitely would have helped but that was the last butt weld piece that I had so I didn't have any more chances to make more attempts but I think you get the idea well that went pretty terrible as I expected so the fit up of it because it was just Sawzall cut wasn't tight and everywhere that there was a little bit of an opening instant hole I turned the welder down literally as low as it would go and as soon as I struck an arc the weld pool would widen out blow a hole so what I wound up doing was simply running some tax now to make sure that this is actually going to last what I would do is wire wheel this whole thing if it was on a car and then weld back over it since the two pieces are joined in that weld is fairly thick with it cleaned off the best I can and running another pass at a little bit higher of a setting will kind of flow it out and if there's any pin dots holes it would smooth that out and fill it so it doesn't leak but let me clean this and we'll go from there well let's take a look at this a little bit of porosity there definitely not pretty or I just did tax it seemed to flow out a little bit look a little bit better so like I said in the situation we got here if this was on an exhaust and you're worried about it being sealed up wire wheel it the best you can turn up your settings a little bit and run another pass over it I'll do that and I'll foreign so without a doubt there's no question that that's sealed all the way around I did Circle ease kind of and I went to just the edge of the toe of the first Weld and then out to the other side now one thing worth mentioning and this is exhaust again so not really a huge issue the wire that I'm using is capable of doing what's called the second pass or it's a multi-pass wire not all flux core wires are designed to do multiple paths but let's be honest it's exhaust it's not the end of the world if you don't use the proper wire I guess oh missed that that's all right overall didn't do too bad other than that not really sure what happened there looks like slag entrapment if you saw that on the exhaust you could go back and do a little tack weld over and it'll be all right again this isn't going in the outer space and if that leaked while it was on the car you would see a puff of smoke out of it which anytime I've welded exhaust I hook a fog machine up to the other end and just check it on a tailpipe to fill a pipe with smoke just to see what's going on if there's any leaks because like I was saying it's pretty common to have a pipe like this up in such an inaccessible place that getting like an A1 quality weld simply is impossible not to mention if you wanted that well for one you'd be TIG welding it on this thin of stuff instead of flux core but I don't know you get the idea not bad I guess that's pretty much it for this video hopefully this stuff helped you if you want to see me do another video or something covering a topic you would like let me know but uh thanks for watching go build something

Channel: Making mistakes with Greg

Views: 100,905

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Id: _5aD0E5Ukz0

Length: 28min 28sec (1708 seconds)

Published: Sat Dec 03 2022