I'm thinking about getting an aluminum topper. I will sleep in it come hunting season (can get very cold). What should I use for insulation? And how would yous guys recommend putting it in? Glue? Tape? Can't see using rivets.
I was leaning towards that insulated sheathing you see at the lumber yards. Or styrofoam? Maybe an inch thick. Maybe more??(?).

 

What style of topper are you looking at? I think that most of your cold is going to come from the steel box of the truck.

 

I'll bet you're right! It is a simple aluminum shell/cap/topper.
Specifically it is a Univover model 100 wiith a bi--level top and a single rear door.
So laying down some sheets on the floor and sides would do well. Gonna have a carpet too.

 

bedrug....would do great for the box insulation

 

My brother had an aluminum top, he picked up some spray adhesive and that pink foam insulation boards,cut to fit in between the frames, and glued them in. He then bought a diy bedliner kit, sprayed over the insulation to make it durable and to protect it. As an added safety measure he then put pieces of conduit pipe to protect it even more, even though it really didn't need it. He might of added 20 pounds to it. It worked so well the beer didn't freeze during our ice fishing trip!

 

Speaking of insulation...
I insulated my camper shell after researching which type (reflectix, foam, bubble crap, etc) would be best. I did the top and sides, and use reflectix for the windows when sleeping, since it is easy to store and whatnot. It doesn't block all the heat coming in, though, so I am looking for something better for that. The pink construction foam boards and reflective layer foam I put on the sides works great, however. I can sleep in when I'm camping in the desert and it actually stays cool in the bed! Now I just need to figure out some kind of solar fan/vent setup to make it even better. Used loctite PL to glue on the insulation as well as some quicker-dry Dap foamy stuff to help hold it there while the PL construction adhesive dried. Threw in a pic of the truck without the shell cause it looks bad ash