Aluminum skin questions?????

I know it has been discussed somewhere, but I got tired of reading all of the posts that came up in my search. What gauge of aluminum is used to skin a TD? I read a few posts where it was said that the skin "floats" instead of being bonded to the sidewall, is there an issue with gluing the skin to the plywood?
I have knocked around the idea of using a 1" square tubing frame and riveting and gluing the skin to the outside, then using 1" foam board insulation and 1/8" panelling inside.
This TD is still in the planning and parts gathering stage, so any information and suggestions are gladly accepted.
I have knocked around the idea of using a 1" square tubing frame and riveting and gluing the skin to the outside, then using 1" foam board insulation and 1/8" panelling inside.
This TD is still in the planning and parts gathering stage, so any information and suggestions are gladly accepted.