Good question Paul, lots of people worry about flash rusting so they rush to get the steel sealed which is a reasonable concern. I've had exposed bare steel in my environment for many weeks with no rusting so I haven't felt the need to rush to epoxy it, the other reason was since I'm doing this in my newly renovated garage and my driveway I didn't want to be spraying that much epoxy and get it all over everything if I could avoid it. Either method works just fine if the epoxy one uses is compatible with using body filler over, I'm probably a little old school on this point and prefer direct to metal with my fillers. Since I'm going to work on the car all this week I'm hoping to have it ready by next weekend to take to the shop and epoxy and paint the bottom and inside and engine compartment and prime the outside so I'm close enough that rusting of the bare steel isn't a concern.