Have welded loads of rusty panels in the past, the only advise I can give you is based solely on my experience.
No welder likes rust, have tried to use a stick welder (MMA) with 1mm welding rods. It generates to much heat, and if your not to quick will burn through. The best results have been using a M.I.G. welder with .60 wire.When you weld just watch the red that is generated from the weld, as soon as it is bright red, stop the weld, you can see the color change, as soon as it cools weld again. Really all I was doing was tack welding. I found it great for filling in holes, using the same weld and cool method.Remember try and clean off as much rust as possible before starting to weld, it will help big time.
We have only been on line for a few weeks and have just started to get some major hits every day.As you move around my blog there are still a few mistakes here and there with the IT stuff, as I am new to all of this. Please feel free to post your current build, sure our other members would like to see it.
Remember it doesn’t cost you a penny to post or take part in my blog, this is the reason I started this site for everyone to share and exchange ideas.