Anyone that tells you that you can get a strong weld with any type of arc weld is most likely full of some kind of compost. One possible method with arc is to heat to 900 to 1000deg f and weld with a nickel alloy of your choice , typically no one is any better than the next as they are all in the range 90k tensile and cast is rarely over 50k.
I think this is your chance to learn to weld cast with a torch and cast iron rod ( cast iron in stick form). I have welded vises and one of them I use every day ,done with cast rod and torch. Basically for a vise if you want success, weld it with a torch , if you want it to fail in use ,arc weld it. I undo a lot of arc weld damage and redo it with torch.
If you want to chat about it send me a phone number and I'll call you.