In researching different chip resistant paints, I came across this website which I found to be a very good tutorial on primers, paints, stone-chip resistant coatings, and metal repair/finishing.
I had not seen it before, and I thought others looking for a top level tutorial on body repair could get some use out of it.
As a bonus, there is a tab on welding body panels too. I am in the middle of one of these projects right now. I wish my Jeep's PO had read this website...I probably wouldn't be re-doing alot of this right now.
Did I mention that one of the fenders has a build up of bondo over 3/8" thick right over the top of a rusted through hole? Arrrrggh!
Here is the link http://www.mig-welding.co.uk/spray-painting.htm