Here I cut the rear seat foam as indicated in the plans using 0.8" Divinycell H-45.
After slurry was applied to the foam, it received two plies UND at 45 degrees.
After knife trimming the edges, I allowed for a full cure. I then proceeded to shape the foam as indicated in the plans.
Removing the center circle foam was a lot more difficult than I thought. I first measured the center of the panel and drew an 8" diameter circle using a compass. I then used an Xacto knife, tracing the circle outline, cutting all the way down to the cured fiberglass (not through the fiberglass). Using a multifunction vibrating saw, I chiseled away as much as I could, being careful not to exceed the cut line. I then used a wire brush and sand paper to remove all remaining finer foam pieces.
Using a box cutter knife, I trimmed out the 45 degree edge.
...and sanded it smooth.
Even though flox corners are not called out in the plans for the rear seat, I figured it wouldn't hurt. Using a dremel (with a cone bit), I carved out a flox groove and applied the flox. I used the same ziplock bag method as I did for the front seat panel.
I then slurried the foam and applied two layers of BID.
I then scissor trimmed the edges...
... knife trimmed and allowed to cure.
And voila... the rear seat back panel is complete!
After completing Chapter 5 (fuselage sides), it was time to make the necessary longeron cutouts and through-holes.
First I tried using the dremel - but for some reason, I couldn't get it stable.
So then I decided to use the all-mighty router! Using a flat bit (with no roller), it went through the fiberglass like butter! I didn't even have to drill pilot holes.