Hi, I am getting ready to replace the floor pans in my 1965 Mustang. I bought a MIG Welder (220V) and plan on practicing before I attempt the welds on the floor pans. My MIG welder has an option for gas. Is it better to use the gas and what wire size and type do you recommend? I dont want to burn a hole in the metal and I understand that it is easy to do so. Any tips or help would be appreciated. Thanks

 

The gas keeps it from spattering so much. You just have to tag it for a spot weld. You have a 220, so you are in good company. Get two or three sizes of wire and practice on different thickness of steel. Once you get the pans welded in, be sure to use seam sealer before you paint the new pans. If the hump has any surface rust, be sure to use some rust encapsulator before painting it.
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With MIG welding, not using gas you have to use Flux Core wire. With gas you can use a solid core wire. Using Gas with MIG welding will produce a much cleaner weld with less splatter.

Setting it up for Gas will cost you extra money though, you may have to buy a regulator, that screws on to the top of the bottle, if your welder didn't come with one. Also you will have to by a bottle of Argon/CO2, I don't know the price but I would guess $50-100 for the bottle of gas.

As for wire size, I would look at what size wire came with the welder and pick the same size, that way you don't have to change the contact tip. I use .035" fluxcore wire on one machine, and .030" solid core wire on the MIG welder with gas.

As for burning holes, try to use a lower setting for wire speed when welding thin sheet metal, and definetly practice on some similar guage sheet metal to see what settings work well. You may want to look and see what your welder recommends, and turn the settings down a little bit from there. (they usually print recommended settings on the inside of the door that flips up)

Doug