Click to view attachment These are the "extra" pieces I have made that will allow for an easy installation:
I bought a 4' piece of 1" x 1" angle aluminum ($9), and cut from it two 17 1/2" lengths, notched at the top, and drilled for screws for side mounting on the air conditioner.
I also bought a piece of Poplar wood ($1.50), 3/4" thick, 2 1/2" wide, and had the store cut it to 17 3/4" in length. When I got it home, I jigsaw cut the radius end curves.
I got these first two items at Home depot.At work I found a scrap of 3/4" thick foam, 2 1/2" wide, and 8"long (free). I cut it into two 4" long pieces and then cut opposite radius curves out of the pieces.
Then I went to
Ridout Plastics, here in San Diego, and dug through their "scraps" bin . I found a leftover piece of 1/2" thick Plexiglas (3 pounds @ $2 per pound), and had them trim it ($12 cutting fee) to 17 1/4" x 6 1/4".