Repairing cast iron with nickel rods

[Big Mick]

I've been asked to try and repair a flue/damper assembly base off a wood burner. I've done the big bits by preheating with a propane torch, welding with 2.5mm pure nickel rods at about 70 amps(I think) and then post heating. This seems to have worked pretty well so far, but I'm missing a small piece of the original casting that was about 1/2" across.
Any suggestions for covering the hole that would be better than just building up with nickel rods until the hole is gone? Is it feasable to use nickel rods to weld a small piece of cast over the hole, or would mild steel be ok.
Sorry, I left my camera at the workshop.

Cheers, Big Mick.

 

[Big Mick]

So I couldn't wait for any replies and welded it up anyway!

Pic. of the damage.

other side.

Welded up with 2.5mm nickel rods. Pre heated with a propane torch.

The other side with the problem hole.

So I decided to try and weld across the gap. Not pretty, but it did the job.

Cheers, Big Mick.

 

[runnach]

Good job Mick, no doubt no replies due to cast being a mystery material to repair, not quiet true, it can be mastered, sometimes on a wing and a prayer!!

 

[Woody.v8]

Good job Mick, no doubt no replies due to cast being a mystery material to repair, not quiet true, it can be mastered, sometimes on a wing and a prayer!!

Your a poet and didnt know it terry

 

[runnach]

The next Bobbie Burns maybe woodie??

 

[busa]

Good job Mick, no doubt no replies due to cast being a mystery material to repair

Cast is no more of a mystery than most other materials, it's just that 9 times out of 10 the job in question is a pain in the ar$e and usually has at least one piece missing. Cast needs careful prep and set up, difficult sometimes as you can't move it around on the tacks like mild steel. With today's rods it welds fairly easily, my favourite being castolin 1010, but like all cast rods they are comparatively very expensive. Try telling a customer that it will cost 20-30 quid in rods alone to repair something that they can replace for 20 quid.