Using a utility knife I cut out two pieces of 63 3/4" x 2 1/2" from the 3/4" Last-a-foam and used a table saw to create the beveled edges as per CC of Figure 7.
The shop temperature was raised to 25 deg C and humidity was 30%.
I mixed a batch of micro slurry: 58g L335 epoxy resin with 22g H340S hardner + 2 spoons of microspheres.
Using a squeegee I applied the micro slurry to both fuselage sides and to the mating surfaces of the beveled pieces and positioned the pieces on the fuselage sides (I had pre-marked the location where they go so I knew where to put the micro and the pieces). I applied pressure to both pieces and wiped away any excess micro with paper towels. I used 5 nails in each piece to temporarily hold the surfaces together and I placed weights on both pieces while they cure overnight.
I ran out of micro slurry part way through so I made a smaller batch using 34g L335 resin and 13g H340S hardner + 1 spoon of microspheres to finish the job.
