So my uncle found this and asked if I knew how to weld cast iron. Would love to try and fix this old stove up but never welded cast. Know you should drill a hole at each end of a crack so it won't spread and pre heating the weld area is also important but what else ? Andy type of perticular rod or wire ? Sorry only have access to mig and stick on my yes welder. Could to DC Tig but not set up for that rn. Thanks

Had a shop teacher in HS that showed us how to weld cast. The big thing I recall was to heat up the cast iron with a torch and then weld. Allow it to cool slowly to prevent spider cracks. I'm sure there are some video on YouTube that can help.

Not much help on welding other then a special rod and a good pre heat, but you can consider brazing too, a lot of cast is brazed when its cracked.

Last cast thing I welded was crack in an exhaust manifold on a '67 Camaro, probably in late '70s.
Heated with oxy-acet then welded.
Held, but put headers on it soon after.

Also sorta brazed thin cast with a coat hanger.

I have "welded a cast bell housing on an old tractor. You want to braze it.....not weld it. Stop drill the ends of the crack and take a grinder and grind that crack open enough to accept the brass when you get it flowing. And.....as mentioned. preheat before brazing. Cleanliness is next to Godliness !

we did it once in welding class , grind out the crack to bevel , hole at each end , special rod , pre heated with rosebud oxy acetylene torch let cool slow

might look at these rods they are what I found searching cast iron welding rods
https://www.muggyweld.com/product/77-cast-iron-welding-rod/

With a CI stove, build a fire inside the stove to slowly bring the temp up to a dull red, weld the crack, and bring temp up again. Then let cool as SLOWLY as possible, like bury it in floor dry/kitty litter and leave it set for a few days to stress relieve the iron.

Vee it out, preheat, arc weld with nickel or stainless rod let it cool slow, no water or braze.

Wolf, cast iron is not the big bug a boo it used to be, there are plenty of stick rods dedicated to cast iron use.

You don't need large diameter rods either 3/32 is probably just right for that once you place a small v in the crack

Cast iron rod has to be run with a tight arc as well so you need to be on the ball with watching the puddle, pre heating is important to help with additional cracking, age of the cast iron is usually the problem with cracking now days, but pre
heating is used to be safe, you don't need to heat it up to any color just get it nice and warm for when you start welding
so it don't tink when you lay a bead on it, if it does you know to take it a bit higher. V it out again and start over, don't go crazy
laying bead on it , just fill up what's needed to even things up

After you done cover it with something heat resistant to let it cool down on it's own.

Most cast iron rods have a lot of nickel in them so you need things real clean as you can get them, don't be worried about
your welding looking all bumpy and messy either, if its old iron it will have a lot of garbage in it, you just keep v'ing it out
and doing it until it looks to your needs. once its hot from welding you don't need to keep preheating it unless you stop
and it cools way off.

You got doubts PM your questions, I have welded up lots of cast iron in my days with all types of machines, I'd not use bronze or brass on it if you wish to have it look close to the same as those fix's just stand out and most will pop if the stove gets real hot
anyway.

Done a fair amount its easier to braze but if you are going to weld it heat the area with a rosebud torch to red hot, weld with high nickel rod then pack in sand to cool slow.

What needs welded on it? Most cast iron stoves are in panels and clamped together with threaded rod.

Grit guy advice is pretty good, I use nickel rod, I’ve even done some gears with a mig welder I was in a bind but they’re still holding, stay away from the dc tig it’s to “perfect” of a weld and cracks worse, personal experience with this, Jodie on tips and tricks welding website has a way to use ac tig but I’ve never done that so I’m not sure.

After looking a little closer if you can bead blast that stove I think would be faster and look pretty good.

I've been told the source of the cast iron makes a difference. American cast being preferred over import... The reason being the foreign stuff gets whatever will melt added to the mix.

Mike