"No Pre-Heat" Cast Iron Welding Repair Technique



good afternoon ladies and gentlemen YouTube Chucky's 2009 and tonight I'm gonna be showing y'all a method for welding cast iron without a preheat this is something taught to me by an old welder buddy and I just figured I'd pass along the Oh so anyway first off a little basic crash course in metallurgy as you probably know by the time you've gotten to the point of researching enough to find this video that when you will a cast iron it requires it can't really take a large temperature shock like for instance this little piece of steel square tube if I wanted weld this thing I could go straight from room temperature actually it's about 20 degrees out here right now to as hot as it's gonna get when i weld it and back and just not worry about a preheat just let it cool in the air be totally fine because it's steel and that's how it works but the problem is cast iron is a little bit different you can't really get away with doing that basically it can't take a very large temperature shock that's why you preheat it you know you take it from room temperature slowly get it all nice and eat it up then weld it and then slowly let it cool back down oh you know why don't you stick it in some kind of oven bury it and sand you know post heat it with a torch and slowly back off the heat whatever you do everything within your power to keep it from experiencing a very large temperature shock now there is a way to weld cast iron without that preheat and that's what I'm gonna be showing you all tonight now basically this is what we're working on this is an old International Harvester out transmission casing and it it doesn't really have a crack so we're just gonna pretend it does and work with what I'm envisioning in my mind here so this is our simulated crack the soapstone line and I just drilled a couple holes at the beginning and the end of the crack and this is important because you know think of how a crack is gonna travel through a piece of material as you know as it's full of water and it freezes and the water is expanding you know it's gonna go straight through the material and then when it gets to a hole drill it'll just it'll stop and just sort of disappear so you have to drill holes at the beginning and ends if you crack or ends plural if it's you know if it's one of those things that branches out and you know this will stop your crack from going you're from growing you're gonna have to drill as deep as the crack goes and it's that's an important step now the next thing we're going to be doing is being this now if we're doing this because as you know you can't just weld over a crack it'll come back in no time so you have to grind the crack out of there and again we're gonna have to go as deep as the crack is now while we're doing this I'm gonna be using an angle grinder you can use a die grinder if you're really patient or have a small crack like one of those Dremel tools just whatever whatever it takes to get this video now the reason I've held off on it is because we're also going to conduct a spark test simultaneously as we're grinding this out and a spark test this as most y'all know when you take a grinder to a piece of material the sparks that gives off will tell you a lot about its composition so we're gonna find out if this is cast iron or if it's cast steel and I'll show you what each of this looks like you know give you a little crash course so hopefully it'll be a cast steel and you can stop screwing around and just weld it with a mag like you would our nice little piece of our square tube here so all right let's start grinding alright ladies and gentlemen so you know know what the sparks that come off this transmission casing look like and so now I'm going to take the grinder to the table here and they match up your luck and you're working with castile a lot easier to Wow on all these problems with cast iron that we're talking about her now your problems and otherwise will continue as we planned yeah they're definitely a lot different and that's because this is what appears to be gray cast iron now I made an entire video on spur testing if that's something you want to learn about and but anyway this is definitely cast the gray cast it's not the hardest type of cast iron to will but it's also far from the easiest it's not very forgiving and it'll be providing a good medium for me to demonstrate this for you guys with so let's get set up and get ready to weld well now it's time to explain this awesome top-secret technique that we got going on here basically if you put a large amount of heat in the cast iron without slowly preheating it and then controlling the rate at which it cools a crack so the trick is to as simple as it sounds just now put all that much heat into it and I how are we gonna do that we're just going to practice some basic heat input control technique so I actually made a video about this too that's the Bell so you want to learn about but basically the plan is that we are gonna start from here and then well to the end of the crack and then start from here well to the beginning of the first well start here well to the beginning of the web we just did this is no this is what's known as back stepping your welds and although the reason we're doing this is because if you just start here and weld here as you go the heats just gonna spread out and build and build and build but if you do the back stepping technique it only grows a little bit and then it stops and what this does is it limits heat input and between and between each of these little welds and when I say little welds I mean like half an inch or 3/4 of an inch definitely not a full inch you know these are definitely gonna be some small welds in between these welds we're gonna let the cast and completely cool shouldn't take long cuz it's really freaking cold out here but you know regardless this is how we're gonna control heat input and hopefully avoid any potential cracking issues so let's get set up and then we'll start welding one other thing as soon as you get done with the well that you're gonna want to peanut immediately which basically just it's a scientifical term for taking a slag chip here and just beating the crap out of it or if you want to go all high-tech redneck you can buy a $20 what should we call air hammer from lives that's where I got mine it works great for this but anyway the reason napintas well is if you had imagined your weld bead and as it cools it's being pulled in all directions and if you hammer on it you're gonna push it out a little bit and that's gonna also work to relieve stress so let's demonstrate and make our first weld so it begins YouTube all right now as you can see we do have a lack of fusion going on over here this would probably require second pass a little bit of touch up there but that's our first well that is not that is not a large well whatsoever and we're gonna wait and let it cool and so you can run your fingers directly over the weld and do this at your own risk if you burn your hands off not my problem and that's cooling pretty quick because I just did this but one other thing I'd like to add in is you know this is probably not a good solution for any kind of cast iron repair you have just you know whatever random kind you can come up with because the weakest parts of a properly done well or at the beginning in the ends and when you do this because you have a bunch of small well it's pretty much all you have it's a beginning and an end in the beginning in the end so you know if it's an engine block or transmission casing or like a water pump housing you know whatever it's probably gonna be okay but if this is some kind of large load bearing cast iron you know structural support probably not the best idea so yep well yeah okay let's do another one all right ladies and gentlemen let's come over here and have a look at the final outcome as you can see it's completely cool to the touch and it's all in one piece there's no cracking to nothing we do have some little metal chips the nickel electrode and gray cast base metal everywhere you know that uh air here we're kind of Sons I'm flying a little bit but just looking up this well and it's definitely pretty well hammered into submission it's a little bit on the concave side it's a little bit low I would probably want to give this thing another pass but you know realistically that's a personal choice I don't doubt this thing would hold your oil I'm just a little bit that way with my welds sometimes but you know as you can see we didn't know preheat we did know post heat and it worked so this is hopefully a technique you can use it will help you I mean if this was fives are pairing mystery customer or something you know I put that extra pass on there then grind it smooth and call it a day it'll hopefully help you out like I said so anyway I hope you all have enjoyed this video I'd like to thank y'all for watching and I don't forget to rate comment and subscribe for more if you're interested in learning more about welding cast iron I'll be posting a few more videos here in the very near future so as always thanks for watching have a nice night everybody yeehaw

21 Comments

  • Funky Junky

    April 14, 2019

    Brother can u recommend to a noob what kind of rod and amp for welding my cast iron pulley to my generic MTD transaxle ??? Wanna swap to a 2 1/2"

    Reply
  • David Burns

    April 14, 2019

    Hey ChuckE, what a great video. Thank you for sharing this technique with us. I like your enthusiasm too.

    Reply
  • James Barrios

    April 14, 2019

    what type of rod you used on your video?

    Reply
  • MrJeep75

    April 14, 2019

    Nice job

    Reply
  • G Grong

    April 14, 2019

    ChuckE question for you. Do you think I could weld cast metal the high carbon stuff with a smaller mig say a 140 Lincoln? If I followed your steps do you think I could puller off? thanks, great job on the vid.

    Reply
  • HaHaHaRich

    April 14, 2019

    Love your vids bro. Very helpful. Could you do a vid on brazing cast aluminum (with torch)? I don't have a tig.

    Reply
  • John Sikes

    April 14, 2019

    Pretty cool (ha ha). Didn't know you could even get away with that. Cast stuff is pretty much junk, from a strength standpoint, to begin with. I think your idea of hammering the weld is a good one, O.W. the cooling shrinkage of the weld probably would cause a the cast material to crack at (or just beyond) the weld to parent metal interface. Nice, I may try this sometime. Your videos are always good, this was no exception.

    Reply
  • Zeke Murphy

    April 14, 2019

    What about if your crack goes all the way through? How would you grind it all the way down?

    Reply
  • jorge garcia

    April 14, 2019

    I have a question probably dumb but the rod you using is it a 6011 ?

    Reply
  • I Build

    April 14, 2019

    What about welding to cast iron exhaust manifolds? They see extreme temps from cold to hot all the time.

    Reply
  • matrixi4i

    April 14, 2019

    You taught me something tonight . Cheers

    Reply
  • Rich B.

    April 14, 2019

    Welding over gear oil is never a good idea whether it's cast iron or not.

    Reply
  • Rodolfo Sante

    April 14, 2019

    What technique is recommended for a DIYer for a Aluminum block engine crack repair?

    Reply
  • Apentogo

    April 14, 2019

    what im dealing with tho isnt a crack but
    a few broken pieces of an ornamental foot mat, theyre broken off-completely.
    is it safe to just…clamp the broken pieces on, drill a hole over the crack and fill it with weld and done! ?
    i mean the crack cant really "travel" anywhere anymore. right?

    Reply
  • James Couch

    April 14, 2019

    Great job of welding and videoing.

    Reply
  • Myo Myint oo

    April 14, 2019

    Thanks for your information.

    Reply
  • fabio40

    April 14, 2019

    I'm wondering if you can use a mig welder to repair cast iron? Any special technique?

    Reply
  • Joey S

    April 14, 2019

    why cant you step weld it from the ends in chucke ?

    Reply
  • Mike Harwood

    April 14, 2019

    Thanks Chuck, another satisfied watcher. I appreciate the time you put into making these videos, and thank you for sharing your knowledge.. Mike

    Reply
  • Brandon Capone

    April 14, 2019

    Interesting good video and something different from all the tig stuff I've viewed the last few years!!!!!!

    Reply
  • Richard Lee

    April 14, 2019

    Thanks! Nice info for a newbie. Now I have a good idea how to avoid those awful cooling cracks (since I have no bucket of hot sand on hand).
    I just remembered being on fire watch at the bottom of a Boston dry dock in 1966, it was right after my ship (Essex) hit the Nautilus. Our bow sonar dome needed a Lot of welding during the repair. There were dozens of large electric heating strips all over the sonar dome. They slowly cooled it down for about a week.?. It was pretty cool down in that dry dock, I think it was around Christmas time.

    Reply

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