Step 7: Installing the Upper Half of the Firewall
This step is a no-brainer and is straight forward. I installed my upper firewall before I installed the center section spar. I was very careful to ensure the firewall was perpendicular to the fuselage centerline.
Step 8: Installing the Turtleback
(Note: I performed this step out of sequence from Cozy Plans.)
I built the entire canopy before finally committing to performing this step. Again, I don't really know why I waited but I must have had some reason, right? All went well with the big flox squeeze. Since I did this so late in the process with the entire canopy/turtleback, I could not get "inside" the plane to scrape away the oozed flox. There's nothing too hard about making the aft cut at the drip rail. Just go slow, be careful, and don't cut too deep. I used the dremel tool to make the cut. I haven't finished the drip rail yet, so check back later. Once I gained access to the inside of the fuselage, I crawled in back and spent some quality time with the grinder and the oozed flox.
Step 9: Engine Mount Reinforcements
The 5-BID exterior wraparound layups are easy to do, but there's nothing pretty about glassing the 8-BID interior reinforcements. First, you have to sit cross-legged for hours facing the wrong way in the back seats. Second, you really have to coax the BID to fit into the corners and around the longerons. Perseverance pays off here. Since I use EZ-Poxy, I knew I'd lose sight of the aluminum inserts in the firewall. EZ-Poxy is dark brown. Any more than 3 layers and you can't see through the dark epoxy. So prior to glassing in the interior reinforcements, I drilled a pilot hole through the aluminum inserts in the firewall, continuing through the cured exterior reinforcements. It helps to have your engine mount on hand to drill the pilot holes to the exact width of the mount. My mount was 3 millimeters too narrow.