i searched on this and only came up with one reply and it was effectively don't weld to cast iron in a structural position.

However, i need to patch a crack in a friends audi 1.8T turbo manifold. This isn't really a structural thing all im looking to do...more likely to have done for him...is the get weld in the hole to seal it up because as of now its blowing exhaust on the turbo centerhousing.

any thoughts from the welding gods?

 

Heat it in an oven and give it a whirl. Remember, it's likely to crack :D

 

i'm not a welding god... but it's all in trainning.

first you have to heat cast... with a torch to get it pretty hot.. then when it's still hot lay your weld with the proper wire/gas combo... it's still not going to be super strong but it should fix your problem... remeber to heat the cast before you weld. and the wire/gas combo i can't think of off hand.. but any welding suply shop should be able to help ya out.

 

Yea cast iron likes to be heated a lot and it needs to be real clen so give a good wirebrush treatment before you heat it, and you need to use a Nickle rod on AC reverse it looks like this Ac- on the welder, if you are going to arc it.

 

also, you should cool the cast down slowly. I put it in lime or sand or something so that it cools down slowly instead of just leaving it in the open air. That will help prevent cracks also.