I am ready to do the rear quarter panels on my 70 Roadrunner. The question is do I lap weld them or butt weld? Is there an advantage to one type or the other? Also are there any things I should be aware of before I cut into my baby. I am aware of the warpage issue and using the stitch method. I read a post a while back where someone mentioned the use of some kind of primer that resist rust in places where you do not have access to after welding. Can you tell me the name of that paint and if there are any special considerations in using it? Do I grind down the welds as i go along, or wait until the whole panel is done? If anyone has pics of a panel they have done in stages or just before grinding I would like to see them if that is possible. The last question is what should I use over the welded area after grinding? (fiber glass, bondo or do you have something that is better than those items)? Thanks for your suggestions!!!