Mig welding cast iron.

[Gritineye]

Is it possible the " well i welded a turbo and its fine" were perhaps a case of the housing being cast steel, rather than the cast iron used for decorative parts and stoves etc?

I think you mat be right there Sean, but I'm not sure..

I tried to use the same method that I used in the turbo bend to weld up a pillar drill part that was cast, I ran a test bead on another spare cast lathe part from same manufacturer which was fine, but the drill part was a whole different story, spat and bubbled but sort of stuck in the end, distorted like mad too!

I was given the DP and no I didn't do the damage!

Nothing ventured nothing gained!

I wonder if soaked in oil might have been the problem, but suspect there are just too many types of cast iron to ever be sure it may be weldable at all..

 

[anto]

Is it possible the " well i welded a turbo and its fine" were perhaps a case of the housing being cast steel, rather than the cast iron used for decorative parts and stoves etc?

Its very possible Sean i honestly wouldnt have a clue of the difference just by looking at it.
Is there an easy way to tell? Colour of grinding sparks?

 

[JRSolutions_82]

I've done it! Stove top (cast Iron). using 2.5 mm 99% ni rods at 70 amps, laid the work piece on some 25 mm ceramic fire blanket and heated using a blow torch, now I don't know how hot it got when heating but definitely too hot to touch, probably about 15 mins minimum of even heating the whole piece, then I welded about 3/4 of an inch at a time, giving each weld 4-5 taps with a light hammer right after it had been laid. The entire lengh of the weld was about 5 inches, but I was near the end when I realized/remembered that I should have jumped about not laying each weld joined straight onto the last, but too late now so carried on. At the end I used the gas torch to keep heating the piece for around 20-30 mins before finally wrapping it round and round with the ceramic blanket, where it has been since, will be going back in a day or two to check on it. I think it went well as there was no horrible cracking/stressing noises at all, and a visual check and no new cracks were visible, done this while re-heating after welding. Only time will tell if it has worked....But the fact that it has not broken in two is enough too keep me happy for the time being.....

 

[shenion]

Sounds like it should work; well done.

I'd have used 55% Ni rods. They are a bit more ductile (and are much easier to grind down.)

 

[ukracer]

Sounds like it should work; well done.

I'd have used 55% Ni rods. They are a bit more ductile (and are much easier to grind down.)

If I was using Tig what sort of rods would I use?/ I dont really want to buy a large pack as its only a small piece of cast I need to add a piece of mild steel to.

 

[JRSolutions_82]

I found arc rods I brought with 5 or 6 wrapped in clingfilm, form less than £10 on flea bay a similar 5kg packet from SIF would have been around £70, but the tig rods are around £40 from SIF. Prices may be higher, I do work for a stockist so get a healthy discount... I think the difference in type of rod is the Ni (nickle) content, I had no real Idea what to go for but choose these just because the seller actually stated how much nickle was in them, but perhaps you'd be better off listening to shenion above....I also used a couple of Ni rods on some mild steel box to practice on before doing the actual repair... Good luck!!

 

[JRSolutions_82]

Sounds like it should work; well done.

I'd have used 55% Ni rods. They are a bit more ductile (and are much easier to grind down.)

Cheers, I was nervous and spent days questioning myself but I am glad now that I went for the preheat approach,sometimes the only way to actually learn is to get stuck in there !