Ni55 rod for fire grate?

Ni55 rod will work, juts v-grind out the crack, preheat your parts, hammer pean each bead with a small hammer when you stop, and bury in ash, lime powder, vermiculite or fine sand to slow the cooling.

Thank you ! Do you recommend short beads so they can be peened while still hot ?

The idea is to peen the welds, thereby pushing the metal down into the weld to reduce shrinkage cracking. So short beads are recommended.

The main principle with all castings (iron, aluminum or bronze) is to try to prevent thermal differentials. You don't want hot zones and cold zones. You want the whole thing warm to start and kept warm as it cools. Short beads means less localized heat.

Got it , and thanks for sharing your knowledge .

The last cast iron item I welded with success was a drill press table. I built an oven out of ceramic cloth, the stuff used for making kilns. I basically wrapped the table in the cloth and then heated to almost red hot with a weed burner torch. After welding I completed the wrapping so that it was completely covered. It took hours to cool. And no cracks. Eric

I'll either stick it in a wood fire or use one of my forge/foundry burners . Wood fire has advantages , like free fuel and using the fire to post heat and cool off . It has disadvantages too , like being a ways from the welder .

I think heating in a reducing atmosphere is probably good. Just so long as you get it hot. I have brazed and welded cast iron many times and the only times I have had it crack was when I didn't pre-heat and cool slowly.

If the weather turns off really cold this repair might just have to wait until spring . Stove is functional with it as-is , and this will be the primary heat source for our new "home" this winter . We have GOT to get more room than we have in this 25' camping trailer or one of us is going to kill the other . Toss-up which way that could go ...

If you can't use Oxy/Acetylene and cast Iron filler, Ni55 is probably the next best thing. Pre- and post-heat, peen, slow cool...

Well , I do have OA , but no cast iron filler ... Hadn't thought about it , guess it's worth checking into . Got all the rest covered . -- Snag