[Akraczek86]

Hey guys! New here. Just bought a LOTOS 175A rig.

Made a mistake, I need to weld steel plates onto a rear car differential (cast iron)
It seems people have had success using a MIG, but most stick it or tig it.

I need help locating the proper wire and gas mixture for the job. It looks like a nickel 55 wire, with a 75 arg/25c02 mix will work? Can someone please chime in? Ill be pissed if I made a mistake and still have to purchase more equipment (stick/tig machine)

Thanks!

[Superiorwelding]

Can you post up a pic of what you are welding? That would make it a lot easier to offer help.

Off cuff, I would say just mig weld it BUT that would depend on the use of said part. If it will see torque it will likely fail.
Jonathan

[Akraczek86]

It will see tremendous amounts of torque. It is a bracket that holds an arm to the rear differential of the car for traction (torque arm)

It looks like I can just buy a stick welder off of Amazon and buy some nickel rods. I will try to get some pictures later, but here is what I will be doing. What do you think?

[Arno]

Diff housings can also be cast steel, not cast-iron. If that's the case then it can be welded normally with a good pre-heat and cooldown to keep everything stable as much as possibile.

May be good to do a small TIG test on a corner somewhere. Light up on the part and melt an edge/corner to a ball. Let it cool down and try running a file over the section.

If the file 'skates' over the section then it's pretty much guaranteed cast-iron as it hardens a lot when it's melted and then re-solidifies. Welding that will need nickel rods to help dilute the carbon content.

If the metal stays pretty much the same as the un-touched area and the file 'bites' into it normally then it's a cast steel or a very low carbon content cast-iron and can usually be welded with regular filler/rods.

Bye, Arno.

[Akraczek86]

Thanks for the reply
It has already been confirmed it is a gray cast iron,
Luckily multiple sources have confirmed
The only thing I need to figure out now is - AC OR DC
Stick welder with nickel rod?
It looks like DC will work and is the cheapest, but some people report the best luck with nickel rod on AC. Problem is, an AC DC capable stick welder is expensive! Would I be ok with a DC only unit?