I finally got a welder (Clarke 130EN) and some metal working tools. Anyways happy with the welder so far, seems to work great. I went to a body shop and got a fender from a newer model car (seems to be thinner than the mustang body parts). Anyways I've been cutting it up a welding it back together, doing only butt welds. Welding sheet metal is not easy. But after doing it several times it is starting to look better. I learned a few things maybe some other first timers could use. Take it slow, allow the metal to cool. I've rushed everyone, but when it comes time to weld on the car I will go extremely slow, so the metal doesn't warp. Tack it over and over, don't try to weld more than a 1/4 inch at a time. Keep tacking until you have very small gaps then weld the gaps. When tacking weld a tack then move several inches away to keep the heat down. Something I want to try is to use a block of copper or aluminum behind the weld as a heat sink, I need to acquire the copper/aluminum. When smoothing the welds I found it best to start with the stone wheel on the grinder for the high spots then use the sand paper on the grinder to finish it up. When grinding/sanding watch out for to much heat (warp the metal). Hope this helps someone. Now to learn how to use body filler & paint.