The F28 bulkhead is pretty simple. I first cut the F28 bulkhead outline per plans using 0.25" thick high density H-250 Divinycell. (I implemented LPC#46 to lower the side notches 0.25"; this will raise the bulkhead up giving a better fit with the canopy later). Also, notice I cut this piece whole. I had plenty of foam left over from the instrument panel foam board (this is also indicated in LPC#23).
I then slurried the foam and applied two plies BID. Knife trimmed and
allowed to cure.
After a full cure, I flipped it over and did the same on the back.
Since I did the previous layup at night, I did not knife trim the edges -
multifunction vibrating cutting tool to the rescue! Here I am trimming the
edges after the panel was cured.
It was very difficult to cut right up against the edge, so I intentionally
left quite a bit of overhang to be trimmed with a router later.
Presenting the router table! I picked this guy up from Home Depot for $80
bucks!! (the bits however are pricey!).
Here is a closeup of the bit I used. I adjusted the height such that the
roller would ride along the foam edge, and the blade would cut the excess
fiberglass completely flush with the foam.
Here it is in action! This method worked so well that I decided to trim the
rest of my bulkheads like this. It gives a perfectly smooth trim right up
against the foam!
After trimming all around, the F28 bulkhead is complete!