Reflectix as a pack frame?

It is way less stiff than a foam sleeping mat. I don't think it would work nearly as well well.

I carried some inside my pack- about 4 thicknesses folded up- and it didn't seem like it would stiffen the pack- though it would pad your back.

I'm thinking of using Reflectix for the bottom of a winter bivy. It is waterproof, puncture resistant, won't stick to snow, and provides some insulation to supplement my pad. I want the full width of the bivy bottom insulated so my gear isn't so cold.

You might get away with glueing some plastic strips to it, like battens in a sail. A folded CCF or self-inflating pad would do as well, so there's no gain for the trouble IMHO. Points for outside the box.

Well, I had to ask… thanks for the confab!

I currently use a double-layer reflectix frame in my REI Flash 18 pack. The two layers are taped together on 3 sides, with the top open. I was looking for something to insulate a camelbak-type bladder and not allow condensation to soak my back or gear inside the pack. I use it with and without a bladder. It is actually quite stiff due to the use of double taped layers. I'm happy with it!

That's what I was thinking about, Daniel– with the main difference being I've a GoLite Pinnacle.