I put this in another thread but I thought I'd start one of its own.

I've been practicing with the flux core welder. I've got some warping going on which if I understand correctly will not be as much of a problem once I hook up the gas. One thing I also noticed is that the metal that's been heated tends to rust faster than the surrounding bare metal. Is this something that will also be reduced when switching to MIG or is there something else that needs to be addressed? I'd hate to have rust between the layers on a lap weld right from the beginning.

Andy

Andy, there was a lot of discussing on a post two days about body filler and rust. Anytime you have a weld, you have to treat it with something or it will rust. 3m has a spray that you can use then weld with that in between the lap, will help it some. The other thing is to sandblast (prefered way) or wire wheel or grind, then spray epoxy primer on it.

You are mig welding wether you use flux core or gas, it's still the same thing, it's mig welding.

If you can spread your welds far apart it will be less prone to warping. The secret is don't get the metal to hot.

Rob

I thought the point of the MIG was for the gas to immerse the weld puddle in non-oxidizing gas. Im not a welding professional but from what I have researced as long as you clean the area soon after welding as long as you use the correct wire and gas you wont get the rusting.

"Metal Inert Gas (MIG) Welding: An arc is struck between a consumable electrode and the sheet metal to be welded. The consumable electrode is in the form of continuous filler metal. An inert gas surrounds the arc and shields it from the ambient to prevent oxidation."

Rod, I'm 64 years old and most of my body shop type friends that are still in the business are old also.

They come over and help and also work with me, they will always try to glue panels when ever they can, and they say anytime you weld on sheet metal you are asking for rust.

One in particular, he has been in the business for 35 years, and he said he didn't like the glueing panels, but, he had to where he worked, now he swears by it.

He asked me how my sons 70 chevelle was looking, we did it quite a few years ago, and he mentioned the bottom of the quarter panel just above the wheel wheel. there was a couple spot welds and the rest of it was glued, he wondered it those spot welds rusted through the paint.

Rob