My friend who does this kind of stuff lectures me all the time about my lack of knowledge about powder coatings says:
"Powder coat is a plastic (Acrylic) so just treat as such for welding and painting."
You can repair powder coat with the new methods out. You put it on mixed with some sort of liquid and fill the scratches or missing area's. Then re-bake it as was done originally.
He has repaired the coating on several parts parts for me.
