Sealing the firewall3h
April 29, 2023
Sealed the firewall using Flamemaster CS-1900 today.
First, I drilled and countersinked the bottom hole that is used to attach the fuel bracket reinforcement angle. Per plans, this hole needs to be countersinked through the F-770 side skin, the F-772 bottom skin, and the F-717 lower longeron. However, I decided to countersink the F-772 and the F-717 lower longeron only, and dimple the F-770 side skin, to avoid the knife edge on the outer skin.
The countersinked skin and the lower longeron.
The dimple in the skin.
Then I sealed the firewall to the side and the bottom skin. I used a Semco sealant gun and a tip that extrudes a flat bead of the sealant. The stuff is kind of thick, but sticks okay to the surfaces.
Then I put every single cleco to keep the parts tight.
Now I need to rivet everything. Since most of the rivets require two people, I need to draft my spouse to help me. Given her availability, it probably would require lots of short sessions over the next weeks.
So far we riveted one row in the F-704 section.