Welding cast iron stove top

[yomax4]

Forgot one important point in the above post: When repairing cracks the first thing to do is drill a 1/4" hole all the way through where the crack ends and/or the beginning if not at an edge. That will keep the crack from growing as you add stress from the welding heat

Yep. You can see it happening in the OP photos. Often the cracks go further than the eye can see. There are products like Magna-Flux to spray on that will show the true path of the cracks.

 

[Kays Supply]

I have had good results welding cast with a nickel rod. I would prep as all above have said, but would only weld a very short pass. Never letting the piece get hotter than I could touch. I would leave it for several hours and then weld an inch or so and repeat until done. It may have been dumb luck, but it has worked several times. Slow but sure.

 

[yomax4]

I have had good results welding cast with a nickel rod. I would prep as all above have said, but would only weld a very short pass. Never letting the piece get hotter than I could touch. I would leave it for several hours and then weld an inch or so and repeat until done. It may have been dumb luck, but it has worked several times. Slow sure.

This is the Modern World way of welding cast. no Pre or Post heat. This has been a more normal way and has been done with good results.. There can be no hurry in fixing cast.

 

[yomax4]

I have had good results welding cast with a nickel rod. I would prep as all above have said, but would only weld a very short pass. Never letting the piece get hotter than I could touch. I would leave it for several hours and then weld an inch or so and repeat until done. It may have been dumb luck, but it has worked several times. Slow sure.

This is the Modern World way of welding cast with Stick. No Pre or Post heat. This has been a more normal way and has been done with good results.. There can be no hurry in fixing cast.

 

[slowzuki]

Thats a pretty big section to preheat and keep post heated. I have welded some with nickel rod, very tough to do right. I have also cheated and used a mig welder. The mig seemed to work quite well to be honest for a low stress part.

 

[deereman75]

What about brazing it with flux coated brazing rods, and an o/a torch? All the cast iron I have repaired with it (one broken dumbbell) has turned out just fine.

 

[Tollster]

Yep. You can see it happening in the OP photos. Often the cracks go further than the eye can see. There are products like Magna-Flux to spray on that will show the true path of the cracks.

You can also use light machine oil and talcum powder. While or soke the piece in light oil and keep it saturated for a few minutes (Brush it on the crack ligaments), then wipe it off thoroughly, then with soap and water lightly wipe the ridual oil off the surface. Let it dry, then sprinkle white baby powder over the area very lightly.
The powder will dram any oil out a crack it has seeped into

This was how it was peformed prior to a dye penetrant (AKA: Manga Flux) examination

 

[jonyyuma]

This is the Modern World way of welding cast with Stick. No Pre or Post heat. This has been a more normal way and has been done with good results.. There can be no hurry in fixing cast.

This how i repaired a engine heat with cracked {Froze}water jacket? One inch at a time and ball peen hammer to relieve the stress, but it was not pot metal or grey? Nickel rods.

 

[weldermike]

Ok, I expect to hear a lot of crap from you guys but here goes. V out crack drill the ends so it cant spread, pre heat w torch. I usually get cherry red then let cool till turns a brownish, straw color, then weld with any cast iron rod I have laying around. Have even used 7018 and mig in a pincch. Take a small hammer and without breaking anything, use your judgement, and slightly beat the weld with the hammer. Heat the area back up with torch, than cover with a welding blanket and let cool slowly. The hammering helps freeze molecules in place and almost stops shrinking process from a liquid to a solid.

 

[Tollster]

Ok, I expect to hear a lot of crap from you guys but here goes. V out crack drill the ends so it cant spread, pre heat w torch. I usually get cherry red then let cool till turns a brownish, straw color, then weld with any cast iron rod I have laying around. Have even used 7018 and mig in a pincch. Take a small hammer and without breaking anything, use your judgement, and slightly beat the weld with the hammer. Heat the area back up with torch, than cover with a welding blanket and let cool slowly. The hammering helps freeze molecules in place and almost stops shrinking process from a liquid to a solid.

Interesting stress relieving method and it seems as though I have heard of this sometime in my career.
I believe the shrinking process is only one of the issues he is dealing with concerning welding a casting.