This is not a required item, but I am told from reliable sources that this makes a big difference on sound, and temperature of the cabin.
Michelle did this entirely herself. THanks Michelle.
First, use poster board to cut out each piece that will need to be put on the firewall. Label each one and make a map .
Then use the poster board template to cut the 3/8 high density foam. Lay everything out. It is easy to mess up where each piece goes.
Spray any type of contact adhesive. I used 3M spray adhesive from Aircraft Spruce. First spray the foam and Aluminum foil and get each piece to have foil on the cabin side. (No Picture for that.)
Then crawl in and spray each section on the firewall one at a time while also spraying the foam as well. Ideally, you want the 2 side to be tacky, about 30 seconds, before applying them together. Once they are together, that's it. For those areas where you need to maneuver the piece around, we found that a heavy layer on the foam alone, and quickly maneuver it into place, works well. You have about 30 seconds before it starts to dry. Here is michelle going into the hole .
Here she is coming out. She does not like this part.
Finally each piece is in place and it looks something like this. Great job Michelle.
Also, to prevent "canning", that annoying tin can sound of a vibrating aluminum plane, you can stick foam back in the fuse, just enough to let the foam absorb some of the racket that goes on back there. I have no idea if this really works, but I am told it does.