Welded Bliss

[warren t claim]

Fooking manicat has broken on the Punto. It can't be migged because the cat is steel and the manifold is cast iron. Any suggestions as to how to fix it?

[Joey spud]

I would give it a try with the Mig,i've had some sucess in welding cracked cast iron manifolds back together.theres was no strengh in the repair but it stopped the leak.

 

Dont know how mild steel to cast would join though,how was it originally joined ??

[warren t claim]

My neighbour is a welder and I've just asked him and he said I need an arc welder and something called similar rods?

[michael1703]

Wouldn't be cast iron, it might be a sandcast steel though (porous pig iron) get it as spotless as possible, drop a 1mm cutting disc into the crack,run the engine so the manifold is hot, turn the gas up a bit higher and don't let it cool too quick, should be fine (not forgetting to disconnect battery whilst welding)

 

If it doesn't cool too quick you should be fine

[Station]

He cant as somebody* broke his mig welder.

[warren t claim]

Can't be migged. Need to find a local arc welder.

[cort16]

I thought arc would be worse given the heat it generates. I think cast iron just tends to disolve if you put too much heat near it.

[Station]

... Yes

[warren t claim]

Even the poor low level jack that that was bought specifically to lift lowered MR2s?

[Station]

No, I've hardly touched that!

[M'coli]

Arc welding cast iron requires nickel rods, I believe.  It's got something to do with similar rates of heat expansion.

[Jikovron]

i welded up a manifold flange where the mounting points had broken off with a view to build up the shape again for drilling ,it was a success only whence forth i got the above mentioned nickel rods as normal ones acted more like a wimpy plasma cutter

 

i remember the internet advice at that time was near enough that its best to heat it like billio then not let it cool ever again once welded