Thread: Treating new welds? car panel

Hi ppl, need advice, did a heap of work on my Hilux 4x4 a cpl of yrs ago, and looked gr8, then last yr all the repair work, new paint on the roof cracked, looks bad both sides, rear sections of roof on the bend, hard to weld, don't think I did it right, obviously. What I am after is advice on doing a repair correctly from go to whoa. Will be removing the filler and then cut out the new sections that cracked, have purchased a metal shear and nibbler to cut the replacement pieces out of a donor door. Correct me please when I am wrong, hole punch around the perimeter, plug weld a sheet as a base, clean up, treat for rust, then place the new piece in, tack, small 1 inch runs going from side to side, to avoid warpage, allowing time to cool, eventually complete seam weld? is this necessary?. Here I need advice when finished, do I treat the weld with a product like ColGal, after grinding down and smoothing of course, still learning, has to be acrylic as my paint will be acrylic, or should I wait till cold and place metal filler on the welds to level then spray Epoxy?Etch primer, any and all advice will be appreciated. Need to keep the metal cancer away.
Many thanks
Waz