Today I fabricated the F-601TD brake line pass through, and riveted it, along with all the rest of the firewall parts fabricated so far( except for the recess cover, which gets installed much later in the build). To hold the firewall steady for riveting, I sandwiched it between two pieces of 3/4" particle board in my bench vise (photo 1). Worked like a charm. I primed the bare steel inside the holes of the engine mount corner brackets with duplicolor self-etching primer on a cotton swab (photo 2).
I shot and bucked every rivet, adjusting air pressure for rivet size and length as necessary. I only had to drill out two rivets, both in one of the F-601J THICK angles of course. I had set them OK, but the shop heads came out quite thin. I had misread the plans and installed -8 lengths instead of -9's. Having to cut -9 rivets down to -8 because there are NO -8 length AN426-4 rivets in either the wing or fuselage kits should have been a clue... :O( I got the two short rivets drilled out without enlarging or damaging either hole, and set the -9's with my tungsten bucking bar and 60psi at the gun.