Here is a view of the aft side of the F-804 bulkhead, which is the carry through structure for the main wing spar.

You can see the gold anodized finish that is on the wing spar and F-804 parts as delivered from Van's. The vertical pieces are primed with Marhyd self-etching primer, because it leaves a nice finish, and those parts will be visible in the cockpit, and they are alclad parts, which means they don't need a real heavy duty corrosion protection. The horizontal angles are primed with an epoxy primer, because they are not alclad (which means they need good corrosion protection), and they will be hidden under the floor boards.

The rectangular hole in the centre is for the tube that connects the front and aft control sticks.

The cockpit floor mounts on the pieces of horizontal angle riveted to the back face of the bulkhead.

The large holes at each side are for the big bolts that attach the wing spars.

Read on for more.

Here is a side view F-804 bulkhead.

You can see the large pieces of aluminum bar that tie the two wing spars together and carry the bending loads.

The front and back pieces of the bulkhead will be riveted together later, during the fuselage construction. I must make a temporary spacer to go between the two parts to hold them at just the right distance apart during fuselage construction to make sure the wing spar will fit properly.