Welding Cast Iron

| August/September 2003

  • SmokStak

  • SmokStak

The following comes from a recent topic on SmokStak, which can be found on the Internet at: smokstak.cgi. As ever, various individuals started, commented on and concluded the following bulletin board thread.

A lot has been said on this site about welding cast iron. I'll admit right off that I have no experience doing this. However, last week in the shop where I work a cast iron part broke in an automatic cutoff machine. To keep things going and to avoid down time, I took the broken part, 'V'-grooved the two broken sections and MIG (metal inert gas) welded them together. I then ground and filed the excess, and got the machine running again. A week later, it's still holding up! Mind you, I wasn't a bit fussy about doing all this because time was of the essence. I had mild steel wire in the MIG welder, using a ratio of 75:25 argon/CO2 gas. So, for what it's worth, it worked for me. - Al

I have had several cast iron parts break a second time at the point that I had brazed the repair correctly. Out of need, I welded them with 0.023 diameter mild steel wire and 100 percent CO2 gas. Working under the same conditions, the parts have not broken again - and I am quite pleased with the looks of the MIG weld on the cast iron. I have no doubt that your MIG weld repairs are holding up fine. - Marty

How would MIG welding a flywheel hub work? - Dave

Based on the experiences I have had welding cast iron with my MIG, I would do it. - Marty

I am a welder by trade, and the best product I know of for welding cast iron is a stick rod called Certanium. It is a very good rod and you don't have to be a pro to use it. - Rod