Ziptie locks, remove the double-face tape, and used Gorilla Super glue. It is still holding strong!

 

I sprayed 3m spray adhesive on the blocks basically coating them and making a big glob over the blocks. But that perferated steel weighs a lot more than mesh or aluminum

 

I made my frame using 1/2" cpvc piping, affixed the expanded metal to the back side of it using self taping screws. The frame itself is held tight against the grill by the core support framing. Been on there for 3 months now and haven't had any issues. Originally used the zip tie blocks but got tired of them popping off even after using glue.

 

After reading almost all the posts on this subject I decided Brattwurzt's and DavidMech21's idea would work the best for me. I would create a removable aluminum panel that would be held in by the removable factory grill. I purchased a 36"x36" piece of .020 aluminum sheet from HomeDepot. Started by cutting a piece to 27"X17", bending the angles using a 1.5" piece of steel angle iron clamped to a work bench and folding over the sheet with a rubber dead blow hammer and then notching areas for clearance with metal shears. After numerous test fits I was satisfied with the fit, cleaned the surfaces with electrical contact cleaner and applied several coats of dark gray Hammertone spray paint. With the 80*+ temperatures and 10% RH; the paint cured quickly.
Have to give Brattwuzt and DavidMech21 credit where credit is due.....