Thread: MIG welding cast iron?

Never tried it with mild steel,only ever used NI-ROD and Alushield heavy.

You can do it with a mig, BUT, bear in mind that the part will go as hard as the hobs of hell around the weld. So hard that the only way to cut it is with a brand new grinding disc. It will only work if the cast iron is very good quality and has NO oil or grease in it. If I was you, I would try to get it repaired professionally or get a new part. Some times it just isn't worth the time to repair.

Could you show us a pic of the broken part? What's it off? Is it under a lot of stress?

Robert

Originally Posted by specialist

You can do it with a mig, BUT, bear in mind that the part will go as hard as the hobs of hell around the weld. So hard that the only way to cut it is with a brand new grinding disc. It will only work if the cast iron is very good quality and has NO oil or grease in it. If I was you, I would try to get it repaired professionally or get a new part. Some times it just isn't worth the time to repair.

Could you show us a pic of the broken part? What's it off? Is it under a lot of stress?

Robert

Gday Robert, after considering that yes it will be under stress it needs to be a strong permanent fix. I wasn't up for having a fool around welding it myself, heating/cooling etc and end up making a meal of it. I also don't want to give it so someone else to repair, because these days if you want something done properly you gotta do it yourself, meaning money and time down the drain.

The part I am repairing is a handle which locks the angle position of a cold saw. It is the only thing the holds the saw in position so it has to be reliable.

I spent most of the afternoon producing a good fix if I dont say myself. There are 4 high tensile bolts involved and no welding. It will be stronger than it originally was. I will be starting a thread on it when I get this fix done, as it is a little bit of a restoration job.

Still want to have a go at MIG welding cast iron though.

Originally Posted by martrix

I spent most of the afternoon producing a good fix if I dont say myself. There are 4 high tensile bolts involved and no welding. It will be stronger than it originally was. I will be starting a thread on it when I get this fix done, as it is a little bit of a restoration job.

Cool - I love this sort of stuff!

In my experience if you are welding with cast iron sticks keep the cast as cool as possible. weld a little then let it cool for a while etc. Using the mig or low hydrogen rods, get the piece hot and keep it hot while welding. To burn any oil etc out of it get it to a dull red. Don't bother trying to drill it though.

A bloke in Cairns welded up the back of an outfeed table for a 6" jointer for me using some sort of hard facing powder.
I didn't see how he did it but it was a very good job.

You can weld cast with a powder sprayer with the right powder, probably not hardfacing powder.

read the topic title people. I am talking solely about MIG welding cast iron, people do it successfully. Nothing to do with ARC welding.

Hi Bob, I love it too...when it works, but takes some persistence. I made a mess of oil filled graphite dust all over my bench, vice, drill, hands etc....

mig welding is arc welding

Originally Posted by aussiecolector

mig welding is arc welding

technically yes. Same, Same but different.

M.I.G.(Metal Insert Gas) Welding is similar in basic principle to arc welding; using a high current to melt a filler metal onto the work – the difference lies in the feed of the filler metal and the method used to combat oxidation. Instead of a filler rod being used to add metal to the work, a continuous wire feed is run through a hand held "gun" from a roll inside the welder.

During the wire feed, inert argon gas is expelled from the nozzle of the gun around the area of the weld, preventing oxidation of the hot metal.

The feed of the gas and wire are controlled by a trigger mechanism on the gun, which when depressed initiates the feed.

The speed of the wire feed and current being put through it can be adjusted and preset on the welder itself. This form of welding is perhaps easier than arc welding, as (if the machine is set up correctly) the user can concentrate on the path of the weld as opposed to the feed of the filler metal, as the welder controls the feed