Replacing Sheet metal on floor
OK, so I'm definitely going to have to replace some whole pieces of flooring. there is some really weak spots as well as some spots completely rusted through from the top where the plywood held water.
The question is: what suggestions so people have for treating/ prepping the side of the new sheet metal that will be facing the ground? Obviously, the face-up side that is inside the bus will get painted with the rest of the floor once I grind down the surface rust in the other spots, but what to do with the parts going face down? Even more concerning, I won't be the one doing the welding so i'll need to instruct the welding guys on how to prep the metal I guess?
Any help from any who has had to replace large sections of the bus floor would be greatly appreciated.