This is some stainless steel I bought from McMaster-Carr. It's 0.020 thick 302 stainless wound in a roll. I bought about 8 feet of it. Pretty expensive stuff (almost $70).

Although my little Di-Acro shear goes through aluminum like butter, this 0.020 thick stainless was about all it could handle. I cut a couple strips off. They were supposed to be 1" wide, but the material shifted during the cut, so the width isn't consistent. I'm going to have to get the holddown bar installed on the shear.

Here's another prototype bracket idea for the insulation. In this case, the flange on the left wouldn't be as long in the final version...I'd make it the same width as the flange on the right. The idea here is that these two ears would have nutplates installed so when I screwed these flanges to the floor, the bracket would create a little box channel for the insulation to go through. I'm trying not to have any penetrations of the foil envelope that will let insulation particulate out. The problem is this bracket is too flimsy. I think I'm going to try just letting screws penetrate the envelope, but sealing up the holes wiht some CS-1900 firewall sealant.

In order to get a feel for how CS-1900 behaves under fire (so to speak), I decided to make a flame testing rig. First step was to acquire and cut some angle pieces.

Here's the rig with torch balanced in position. It'll be blasting on a 1 ft x 1 ft piece of stainless.