Big bass,this may help next time yo run into rust,and a patch panel is not avalible.as long as you've got the basic structure of the shape,which in the fender you did.start buy cutting a piece of sheet metal large enough to cover all or more of the rusted area,now place your patch over the rusted area,leaving the rusted metal there for now!clamp or screw one end of the patch to the panel,in this case I would start at the bottom flange.you may want to put the first bend in it with a small sheet metal brake to get started,now take your torch and gently warm the metal as you form it over the old shape,using a body hammer and heat gently tap and massage the metal into it's shape,you may need to make a few relief cut's with the cut off wheel in the real curved area's,but they can be welded up later .after you've made your patch,cut the rust out and install the fabbed part
