trying to understand movement

admin

I am trying to patch in a fender lip on a restoration project. I read through  the archives before attempting to try and eliminate any warpage. I was 100% successful on other areas of the car (rockers, quarters etc). I couldn't have asked for a better result. However these 2 (right & left) fender lips have me stumped. In the attached photo the circled area is where I get the warp. If I cut where you see the black lines, about an inch on the vertical and 1 to 2 on the horizontal the panel returns to its original shape. I am about to try a third attempt but figured I would end up with the same result. Is there some thing I can do differently to get a better result? I am using a Lincoln MIG. I have taken a ton of time to keep the heat build up at a minimum. I don't understand which way the metal is moving to try and prevent the warp. It sucks that a 2" weld can screw up a decent panel when the first 10" didn't affect it at all.Thanks- Mark Attached Images