Heater Box, Firewall Recess, Fuel Vents

I drilled the mounting holes in the firewall for the heater box.  Here I just have a couple of AN3-4A bolts temporarily holding it on.  I have some AN3C-4A bolts on order for the permanent attachment.

I prepped the firewall recess for riveting by deburring the rest of the edges, dimpling all around, and riveting the sides.  I dimpled these holes as well so the recess will be flush on the inside.

I started fabricating one of the fuel vent fittings by taking an AN832-4D bulkhead fitting and sanding off the threads on the short end and cutting a 45º bevel in the end  I’ll proseal a small stainless steel vent over the end to keep bugs out.