Cutting the hole

[Airbag]

Gus your speaking me lingo, I was thinking doubler. Maybe with some NAS1097 rivets or hell maybe some Hi-Locs. You must have done a little aircraft sheetmetal at one time?

[gus]

Rick,

Do the doubler before cutting the hole (I probably don't need to tell you this since you are a sheet metal man!!) because the roof curve (at least on a GMC.) is hard to keep under control once the cut is made.

I've only made a cut for a refrig vent which was right on the side at the smallest radius of the roof curve, it was hell.

Don't know about any framing but I suspect it would be pretty hard to do with the original bus ceiling still in place. As I remember the ceiling is about 4-5" below the roof and is a mess to cut, it is some kind of very brittle pressed hardboard.