Cast iron repair

[txfireguy2003]

Okay brain trust, I've got a problem and need experienced advice. I have a broken cast iron part for which there is no easily sourced replacement. I can weld, but have never had good success with cast iron, even using nickel rods. Heres what I have, how would you go about fixing it? Epoxy? Solder/ braise? Weld? I've thought about drilling and tapping to use screws or pins as reinforcements, then epoxy or silver solder. Also considered taking it to a welding shop who has good luck with cast parts. What would you guys suggest? I figure I've got about one shot to get it right. Machinists will know what this is and how critical it is.

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[easeup]

put that one in the oven to 375 for about 3 hrs first. then use your nickel rod to stick it. put it back in the oven and let it cool down at about 50f per hr.

[Gunnyart]

I welded up the water pump housing from my dad's MG with success.

I used MIG with stainless wire.
After grinding to clean metal I heated it in my gas grill on max temp for an hour.
Then I buried it in a pot of sand with only the portion to be welded exposed.
I welded it (with a steel stud in the hole where it was broken out) and the broken bit clamped to it.
Then I quickly buried it in sand and put it back in the grill and let it cool down very slowly.

Worked like a champ!

[White Falcon]

This!
Down size pic would help also. Cast must cool down very very slow.

put that one in the oven to 375 for about 3 hrs first. then use your nickel rod to stick it. put it back in the oven and let it cool down at about 50f per hr.

[txfireguy2003]

This!

Down size pic would help also. Cast must cool down very very slow.

Sorry, uploaded pics with Tapatalk from my phone. They look fine in the app, not sure what they look like on a computer screen.

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[bmac]

Oven is the best way to preheat and be consistent. As you weld make sure you ping to relieve stresses. They also make a sand you can place it in to help retain heat to slow the cooling process.


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[RifleBowPistol]

Yep, I have been taught to preheat cast metal, both iron and aluminum before welding. I was taught to heat the part to 350 degrees, depending on the size of the piece as to how long it needs to be heated to get the whole piece up to temp. Once it's welded, don't weld on it very long, put it right back in the oven. Let the temp stabilize, then pull it back out and weld some more, stop put part back in the oven. Let temps stabilize and then pull back out to weld again, if more welding is needed. Once done with the welding, put it back in the oven let it stabilize temp, then slowly cool the part.
I was also taught that after you are done welding, take a piece of wood, such as a 2X4 put on one end of the part and smack it with a hammer fairly hard a few times, before putting back the oven for the last time.

Also it is very important, that the part be baked long enough for the piece to degas. Basically one of the reasons for baking it, is to bake out any chemicals in the pours of the metal, also another reason, it needs to be baked at high enough temps to boil or evaporate any chemicals out of the metal.

As for the welding, there is a process that works very well, not sure where to get the product, but I have seen the end result, it's very good. I personally have welded cast iron parts with nickel rods, was not overly impressed with the results. I was trying to weld up inside some exhaust ports, had the rods at quite a bit of angle to the surface being welded. Still did not like the results. I have welded many parts with a MIG with just common steel wire and gotten pretty good results.

I know of a guy who is outside of San Antonio, who is very good at welding cast iron, he repairs cast iron pieces for guys all over the country. But if you search around, there is likely someone in your area who also welds cast iron. Typically industrial machine shops either weld cast iron themselves or know of someone they can send pieces to, to be repaired. It is common to weld up industrial diesel blocks, when a rod has gone through the side.

So that's off of a lathe, correct? So it very important to weld it back together, with it both pieces put together correctly.

[txfireguy2003]

Yep, I have been taught to preheat cast metal, both iron and aluminum before welding. I was taught to heat the part to 350 degrees, depending on the size of the piece as to how long it needs to be heated to get the whole piece up to temp. Once it's welded, don't weld on it very long, put it right back in the oven. Let the temp stabilize, then pull it back out and weld some more, stop put part back in the oven. Let temps stabilize and then pull back out to weld again, if more welding is needed. Once done with the welding, put it back in the oven let it stabilize temp, then slowly cool the part.
I was also taught that after you are done welding, take a piece of wood, such as a 2X4 put on one end of the part and smack it with a hammer fairly hard a few times, before putting back the oven for the last time.

Also it is very important, that the part be baked long enough for the piece to degas. Basically one of the reasons for baking it, is to bake out any chemicals in the pours of the metal, also another reason, it needs to be baked at high enough temps to boil or evaporate any chemicals out of the metal.

As for the welding, there is a process that works very well, not sure where to get the product, but I have seen the end result, it's very good. I personally have welded cast iron parts with nickel rods, was not overly impressed with the results. I was trying to weld up inside some exhaust ports, had the rods at quite a bit of angle to the surface being welded. Still did not like the results. I have welded many parts with a MIG with just common steel wire and gotten pretty good results.

I know of a guy who is outside of San Antonio, who is very good at welding cast iron, he repairs cast iron pieces for guys all over the country. But if you search around, there is likely someone in your area who also welds cast iron. Typically industrial machine shops either weld cast iron themselves or know of someone they can send pieces to, to be repaired. It is common to weld up industrial diesel blocks, when a rod has gone through the side.

So that's off of a lathe, correct? So it very important to weld it back together, with it both pieces put together correctly.

It's actually off of a milling machine. Luckily, the broken bore will still hold the brass feed nuts without the broken off piece, so getting it perfect may not be 100% critical, but the closer the better obviously. The real issue is that without the bottom section, the machine will not feed in one direction. I really just need that bottom section stuck to the top section with a decent amount of strength. I don't think it experiences a ton of stress in normal operation. In fact, it was working in this broken state until I tried to adjust the backlash, then it fell out of its place and wouldn't go back.

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[Dale Moser]

I would be shocked if Draco couldn’t handle that.


Cosmiccowboy could do that, but I have not seen him around in a long time.




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[Txtourist]

Can they weld some washers or machined rings on the ends with the same nickel rods? Snapped a cast part on a 3pt that was repaired that way plus heat and nickel.

[deerplanter]

Why not make another one? I've had parts like that welded up with little success and have had some made from cast, expensive I've had the best luck with a machine shop making new one out of steel.

[txfireguy2003]

Why not make another one? I've had parts like that welded up with little success and have had some made from cast, expensive I've had the best luck with a machine shop making new one out of steel.

I've considered that as well, but a repair is going to be cheaper and faster I'd imagine. If it breaks again, that's the route I'll go, but it's a somewhat detailed part with two perpendicular bores, keyways, screw holes etc. I'm not sure I want to pay for that much design and machine time, but I guess I will if I have to.

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[hpdrifter]

we used to get some rods back why I worked for Mobil Pipeline.

They worked real well. I'm no welder and could do pretty good with them.

Something like Castalloy.....not too sure.

Pretty sure a sure enough welder could do pretty good.

[Big Lee]

In Killeen, Elijah Baker. Man can weld anything. His shop is attached to Killeen feed store on 195

[boh347]

Yup what everyone else said, preheat and ping.
I’ve brazed cast iron with brass and welded with nickel rod.


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