Welding Cast Iron Repair using 7018 Welding Rods. Cast iron can be tricky to repair because it wants to crack from welding. For this repair I stick welded cast iron to cast iron using 7018 welding electrodes and then I tried stick welding cast iron to mild steel using the same 7018 welding electrodes. This repair was done using the cold method, meaning no preheat or post heat was used. Follow along as I demonstrate how to repair cast iron using 7018 welding rods. Disclaimer: This is for entertainment purposes only. Do not weld your cast iron cookware. You could poison yourself.
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Disclaimer: These videos are intended for entertainment purposes only and as such, you should not attempt to do any of the things you see me doing. Always read and follow the manufacturer’s safety guidelines before handling tools. Seek professional advice and training before using any welding equipment. Never operate any tool without wearing the proper personal protective equipment. Final warning, Do not attempt to do any of the things you see me doing!
This is a cast iron repair series. We all know that brazing / silicon bronze or nickle are traditional repair methods, but what about methods and fillers not usually associated with cast iron repairs? We are experimenting with different processes and different filler metals with preheat and without. There are many ways to repair cast iron, If you ask 20 people how to properly repair it, you will get 20 different answers. Do you guys have any cast iron repair stories to share?
This is part of a series so it was the rod selected for the test. There may have been one other rod that tested higher in the series but it wasn't by much. I considered it a success...especially when you compare the cost vs performance to a specialty rod.
Glad you have good results with this
I on the other hand have to use HEAT , Heat and more heat for best results.
That is my best vice Hot enough that the cast and the 7018 puddle together.
Peen it all out the same way as this video and wrap it in isolation to where it
was still too hot to touch the next day when I checked it out. Left it alone to
finish cooling down very slowly and it still is holding.
Very nice! I think the reason this worked without preheat is because I welded very short beads and allowed it to cool to touch before I welded another bead. As you said, preheat and insulated cool down is the safest bet though. Cheers
Thanks Gary! I've been wondering the same, so I'm going to do a video doing just that! It should be out in a couple weeks. I get a lot of criticism when I do that type of video, so be sure to hit the notifications bell...I'm sure the comments will be interesting :) take care brother!
If you are trying to weld a crack in an engine block or cylinder head, it's very difficult and I would say that even if by chance you seemed to have welded it with 7018, it wouldn't hold up because of the difference in expansion rates of the metals.
I have never tried to weld and engine block or a cylinder head with 7018, but one of the commenters below actually posted that he welded up a cracked cylinder head and the repair lasted for many years. Another poster said he welded an old tractor axle...If that's all you got, It appears it can be done.
Thank you for your comment. This is a series where we are experimenting with different processes and filler metals... Last week we experimented with nickel rods / no pre-heat and TIG. We are trying different things and seeing what works and what doesn't and then doing a crude testing method to see how things shake out. Yes I know ESAB.
Thanks for your comment...yes, mig welding has worked on a few occasions. This is part of a series where we are trying different processes and filler metals. Another viewer mentioned flux core, so that very well could be in an upcoming video! Cheers
If that joint has broken 3 times now, either the skillet is made of inferior iron or your welding skills are AWOL. Being that you're cold-welding it with 7018, the latter is probably the case. When cold-welding (ie with no appreciable pre-heat), Silicon Bronze brazing is the only thing that will hold up. If you're just gonna keep welding it back together with 7018 and no pre-heat, you might as well just sell your welder and buy a new set of pans with the money you get from it lol. I certainly wouldn't trust anything you've welded after seeing this video. Just sayin...
INF1D3L010 No worries man that seems to be a common misconception amongst some in the welding community that there is only one way to weld cast iron and that’s simply just not true. Many others including myself have successfully used various filling metals some with preheat some without and have produced solid long lasting repairs. And yes we all know tig brazing with silicon bronze and nickel rod is also great repair, that’s not what this series is about. We are experimenting and trying new things and finding out what works and what doesn’t. There are many ways to repair and weld cast iron. If you asked 20 people you’ll get 20 different answers
You act like you're telling me something I don't know lol. I already know the best way to re-join those two pieces together, and that's by TIG brazing it with silicon bronze filler. That's pretty much the only way you can "weld" cold cast iron together. You could skip all the tests and go straight to what is known to work. Not trying to be a prick... Just sayin...
Thank you for your comment. It's called the cold welding technique. Normally cast iron is pre heated then welded and its cooling rate is controlled. I'm not breaking it and welding it back together each week using the same fillers. This is part of a video series where we are trying different filler materials and different welding processes. Cast iron is very different than mild steel.
I don't know what you're trying to prove, using a 7018. There are so many cast iron rods on the market, and I have used some of them with great success. The best one I have ever used was a certainum 889. But I have used other brands with good results.
If u hook the welder up backwards and use the ground rod for the rod it will draw the heat out and will have hardly any heat and no cracks I do it all the time a old man told me years ago and I've made a lot of money using it try it on hear as a test no leaks eather.
I think you are the 2nd person that has mentioned this in the last year or so....I had not heard of this before and I have not tried it yet. I am very curious to see how this works. It makes sense. Are you using an AC welder when you do this?
I used to be a industrial mechanic back in the eighties, had a broken cast iron arm that traveled on a roller on our wool scouring line. I was going to weld it with 7018 low hydrogen on dc current. one of the business owners said you can't weld cast iron. ( he was my department head.) I did it anyway and it lasted 7 years until we replaced the whole scouring line.
Nice...The one thing I'm learning by sharing this information is that everyone seems to think there way is only one way and there way is the right way. As you discovered, there are a bunch of ways...some are more unconventional than others. Good on you for giving it a go...it bet boss man was happy at the end of the day... you saved him a pile of cash :)
Dylan Crow I agree 100%. The only reason I used a cast iron skillet for this demonstration was so no one could claim its cast steel or some other metal. I think universally everyone can agree it’s made of cast iron. I get a lot of criticism whenever I do cast iron repair videos, so I figured I remove one variable that people could argue about. I think I paid less than 10 bucks for the pan so no big loss to just scrap it. Thanks for your support.
61Benster 👍 i actually bought this pan specifically to destroy, weld and test. I have no intention on using it again. I might have considered it, but the first repair that was done was using nickel rod and nickel is a carcinogen so it’s a no go for me after that. Thanks brother!
+Brandon Lund I'm a certified welder/fabricator. On the handle you could've preheated and then ran a 6010 root, grind the face and hot pass 3/32 7018 and then ran the 1/8 cover. On the inside, you would grind out all the trash down to the root and run 3/32 7018 hot pass and 1/8 7018 cover. Grind it all down flush and post heat.
Yeah the pin holes, make the area weak. So you have to grind them out. That's why i said a CJP (complete joint penetration) weld would work.
I haven’t tried a pre/post heat dissimilar repair with cast/carbon/7018 so I can’t really can’t say for sure if it would have worked. The bottom is a tough repair anyways because it’s effected radially as opposed to the handle that could expand outwards. I had it grooved fairly deep. I was more trying to see how the repair would work doing the cold method with 7018. As I’m sure your aware, it’s pretty common to have trash float to the top and create those little worm holes. You would not normally see them unless your grind it, which I could have filled again. For this demonstration, it was not really necessary. Are you a pipeliner by chance? Thanks for the comment brother.
My whole family is nothing but workers. My father is the type of guy that would rather conversate and socialize with people and dont get me wrong theres nothing wrong with that I would just rather be a diesel mechanic and also a welder. Thanks brotha keep up the informational videos!
+Brandon Lund Yeah, it just takes skill and patience, like anything else. I don't know what, say, aerospace engineers do, but if you take it slow and follow the same process as you said you're going to get usable results.
I've actually repaired some fairly critical pieces using 7018, including a heavy duty cast iron vise and it's still going strong after almost 10 years. It's just another tool to have in your toolbox if your in a pinch.
Ok americans just how large is a 1/8" rod?
Is it a 2,5mm rod? Or even a 3,2mm?
Would not weld with any of those on just 50A thou.
Well 70.18 like Esab ok 48.00's are ok to weld cast Iron if it's just a quick fix.
My opinion on the reasons why you got crack in the middle - is different from yours. I think it happend not because of materials being dissimilar, but because of geometry. That cast iron in the middle of your frying pen had no room to move during its contruction when cooling. Your weld was all surrounded by very hard (and "strong") cast iron. That cast iron did not let it move, so it had to crack. Contrary to that, when you welded that round piece at the edge of the frying pen, it could easily expand to outside and then safely move back when shrinking. Thus avoiding cracks.
Good point and I agree with this. I also think the 7018 rod does not have the elongation charasticistics as other rods which are more compatible with welding cast iron. Im thinking nickel might have done the trick without cracking but I didnt want to use nickel because it's a carcinogen. Thanks for the great comment!
Nah, I paid $7 for this one and I've smashed it, weight tested it until it breaks and welded it back together 3 different times using different processes and welding rods. I've definately got my money's worth.
they make welding rods for welding cast iron to steel,steel to stainless steel, and stainless to cast iron. look up dissimilar metals welding rods. they are also called maintenance rods. they have a very high tensile strength. nickel rods are a joke.
I think he is well aware of the different rods made for cast iron to steel ect, the point of the video however was to see how 7018 would preform. Better then I expected but I think his success was in the technique.
Lucas Knie, your example with hitting nut on a rusted bolt is a good example. I like it. I myself did not even look at it this way before.
My imperfection in English is not that bad that I would had difficulty of not catching right away the difference between shrinking and expansion :) I was talking about your phrase "... but the cast will not...", not about me not understanding the difference between shrinking and expansion. For a minute I was thinking that you were talking about "cast" - as about "mold", "detail" (and I thought that I just did not catch this.)
But no: you are talking about "cast" as "cast iron", material, metal. So I am withdrawing my words that I did not understand your words because of my English, and my position stays the same: you worded this particular phrase "...but the cast will not..." badly, exactly as I described in my previous comment.
I checked in Google: thermal expansion for a cast iron is about 10 percent less than thermal expansion for iron. It just means it would shrink slightly less than iron, rather helping us to avoid even more cracks.
Upd: Sorry, I only now got that you were talking about heating the rusted nut, not about hitting it with hammer. My bad. But still a good example, though a little bit out of subject of our disscussion, on my opinion.
+Alek Rudy so as a non native English speaker it makes sense you wouldn't understand. Shrinking means going from bigger to smaller. Hence, when you peening it, it makes it "expand- meaning smaller to bigger." Cast does expand and contract like every other steel. Just not nearly as much. The expansion is like the concept of heating a nut to free it from a rusted bolt. It causes the nut to expand, breaking the rust seal. Then after it cools, it shrinks back down to size. It is a factor causing warpage as well.
Lucas Knie, I disagree with your statement that I said the same thing you did. You said: " ..the concept behind peening is to decrease shrinkage (when welding cast iron with 7018-th).' While I am saying: When using peening when welding cast iron with 7018-th, we COMPENSATE the shrinkage of brittle cast iron for the cost of deposited soft 7018 metal, hard hitting 7018 metal with a welding hammer, making dents on its surface and forcing it to actually EXPAND towards contracting cast iron.
Another you phrase, in my humble opinion, is worded bad and unclear: "...your weld will start to shrink, but the cast will not..."
You had to specify: "...your weld will start to shrink, but the big massive body of cast iron around your weld will not follow the shrinkage of your weld, thus causing tension and therefore cracks along the weld. You had to preheat the whole massive cast iron workpiece, so after welding the whole cast iron detail would shrink together with your weld, thus avoiding creation of tension and cracks."
Sorry, Sir, but right now this your phrase sounds like cast iron is not subjected to heat shrinkage as a material... At least to me, as to a non-native English speaker...
I used to have access to a huge forge that could be closed. I have put deep bevels for full penetration on cast iron. Then gotten the parts red hot and welded at super low amps. Then cycled in and out of the forge to keep the parts hot. After completion of welding back into forge red hot for 15 minutes then close lid and shut forge down. 24 hours later part still to hot to touch. At 2 days part is cooled to room temp. Using that method I successfully welded cast iron with 7018 stick many times.
MG 289 rods are excellent for this type of repair, but expensive. If you get a lot of porosity then butter it with Normacast first. You may also want to try Washington alloys Tensile weld or 312 stainless. There are so many other options besides nickel rod depending on the base metal condition. 7018 does work. I have also had good luck MIG welding some exhaust manifolds on import cars with 70S-2 wire. You don't know until you try. Good video!
Thanks bud, I appreciate your support! You hit the nail on the head when you said "You don't know until you try". Thats what this is all about! I repaired a broken off leg from a cast iron park bench using 70s2 MIG and it worked like a charm. I did pre and post heat for that one. I'll have to check out the MG 289 and Washington Alloys rods.
Always thought it was a bad idea to grind cast iron before welding as it just adds more contaminants from the grinding process, and the only real option to prep the pieces is a chisel. Am I totally incorrect?
+pedrosixfourthanks brother! I have a few boxes of gouging rods but I've never tried using them on an inverter welder. I might have to give it a go and see what happens. I knew you were just asking, i didnt take take your comment in a negative way 👍
Yes and no...the best method is to use gouging electrodes. The gouging rods will bevel out the joint while burning out any oil and contaminants. The next best method is to use a die grinder with a metal cutter (not a stone) and lastly to use an abrasive wheel. You could use a chisel but I've never tried....does any of this matter? Probably not for most repairs. I've had excellent results with preheat, welding / peining and then burying in sand.
+Angelo Joson Glad I could help. Here is a link to some more cast iron repair videos. I think it will start with this video, but you can skip to the next. Cast iron is fun to work with because there are so many ways to repair it. Thanks for watching and I'm glad you enjoy! https://www.youtube.com/watch?v=9pMbeG7QVZA&list=PLfbf78fMz9VqxPZTT-xmwdcrHVa7ML-ft
Absolutely not. If you did a full weld, It would cause the cast iron to crack. When you dont use a preheat, you have to keep the heat input very low, which is why you always (even with preheat) limit the amount of heat you put into the part. .
+ZenMinus that's sad. Where I live (Maine) paper mills were huge business 20 years ago. They employed thousands. The paper industry dried up and went overseas and now massive warehouses sit vacant and town populations were wiped out because mill workers moved away when the jobs were gone. It's sad when local jobs get shipped away overseas and huge corporations put the little guy out of business. Take care and I appreciate your support!
+Brandon Lund The manufacturing and repair industry and engineering in general is VERY limited in Australia. The combination of VERY HIGH union wages, cheap imports and cheaper manufacturing facilities in China killed off most of Australia's industrial capability. Australia's population is too small to be self sustaining. MANY small businesses have been wiped out by larger corporations. The "local hardware store" was wiped out 10-15 years ago we just have ONE enormous hardware chain (Bunnings) and a couple of smaller hardware chain stores. I could go on.....
+ZenMinus I agree with your comment. I was just saying that not everyone has an oxy rig setup. I've heard from other folks in Australia that cast iron rod is no longer available? Why was it discontinued? It is still available here in the states. Cheers brother!
+Brandon Lund ...but I was referring to the central patch of dissimilar metal.
The best way to weld cast iron is with a cast iron welding rod and oxy outfit. This also requires pre & post heat. The result is an almost invisible join, as the cast iron rod welding rod melds with the main material.
I don't know if you can obtain cast iron rods now. They are not available in Australia.
+Brandon Lund - yes spent few years in Vermont, in Southern New England now. I'm doing a few projects with the welder fixing a trailer and might fix a crack in a wood stove. It how I found your cast iron video.
+Vermonster90 I took a pause for a few years too so I understand where your coming from. That sounds like a neat rig you just bought. I'm glad to hear your getting back into welding. So I have to ask...are you a fellow New Englander? The reason I ask is that the word Vermont is part of your screen name. Cheers
+Brandon Lund great explanation didn't realize that was the case, I am just getting back into welding after 31 year pause. Bought a flux mig and 3 in 1 tig stick plasma cutter box. Am checking out vids and looking forward to getting back at it.
Vermonster90 so when someone decides to use nickel rod, which is a carcinogen and they decide I’m to blame for poisoning them. Same reason McDonald’s needs to warm people on their coffee cups “caution coffee is hot”. Lack of common sense
Good test, gotta love the 7018! Lots of stuff still holding with those rods, its been my go to rod for years, have you ever tried any certainium 704? They supposed to be for dissimilar and unknown base metals, i think there 100k psi, i have a pack of them someone gave me, run just like the 7018, great video and test, thanks
You also have the option of using a rod meant for cast iron or a nickel rod would work much better than 7018 which would probably break pretty easily when you drop it. As far as the pre heat goes you don't necessarily need to pre heat thinner cast iron more so the thicker cast iron because the heat escapes so fast. And you're welding downhill is a big no no.
R Reichel, this is an ongoing series. Last week we used nickel rod and tested, the week prior was a different process also. 7018 has decedent elongation as compared to other electrodes. Vertical down helps reduce heat imput, especially with a rod not typically designed for cast iron and without a pre heat.
MAC VENA this is an ongoing series. I have been experimenting with a bunch of different repair processes and methods repairing cast iron. So far nickle rod made by muggy weld has come out on top, but as I mentioned in the video, it's just another tool in the toolbox. If you go to the beginner welding series playlist, you will see some cast iron welding and testing videos that you might find interesting.
@ Nimbus. For about the same price you get better with the 312, the 309 being already good on cast steel.
The use of the 312 on cast iron is not "official" but since more than 40 years it has been used at least in Europe. As the 312 has an elongation to break of 23% with a yield of 115000 PSI it's able to absorb almost all the thermal movements of the cast iron during the reparation, plus local stresses, vibrations and so on. It replaces in most of the cases the very expensive nickel rods and the indecently expensive very hard to find hastelloy rods. The 312 can be machined and needs only a simple rod welder like a cheap Chinese 200 bucks inverter which are now pretty good.
The lone competitor I know is a AC TIG with pulse welder (more than 3000 bucks) with argon and aluminium bronze metal filler, but it's a professional tool for a rather skilled guy...
There is far better choice than a 308 made for welding 304 nothing more. the 309 is for welding stainless steel to ordinary steel, little more use. The SS 312. was Invented for welding gas turbine blades. It's very strong (more than the 7018), but it remains ductile with no fragility to vibrations, thermal shocks and other miseries.
It's the better choice for welding unknown or dissimilar steels, high alloyed steels, and also cast iron (as it works at low amps, is very ductile, and does not form brittle compounds). I've used it extensively for for professional repairs: crankshafts, difficult steels (special alloys, springs, tooling steel etc...) and cast iron (beds, pianos, engines, compressors, pumps, exhaust collectors,etc...).
In some cases alu bronze AC Tig or nickel alloys are more indicated at high cost but the 312 can handle 90 % of the repairs. The price is moderate and it's the easiest rod in the world. On 85 % of the repairs on cast iron, if you are clever and methodical no preheating is needed. That's useful when you have to repair urgently a crack on a diesel engine inside the cramped machine room of a fishing boat.
Hmmmmmm. I'm going to have to do some research. I have not heard of this rod. I'm glad your enjoying the content. I enjoy doing this type of video also so yes, you can expect more in the near furure... probably this Friday 😁
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