In the floorboards of my comet and the trunk are really rusted, do I use rust preventitave paint? Or is there a better way
Depends on how rusted...If its just surface rust and some pitting...You can treat it with a rust remover/neutralizer. then top coat it. If it rusted through and looks like swiss cheese...It needs to be cut out and replaced.
Fully agree - I replaced quite a bit of metal on my Maverick - everything got a coat or two of Rust Bullet Black Shell after welding
Visit ACE Hardware for some OSPHO and a cheap throw-away paint brush.. A small bottle will do a large area..It will check the rust and turn the metal black . Done this on several items and THEN made the metal repairs. Cometized (Chip)