Here's my firewall passtrough on the upper right (co-pilot) side of the plane. This is modeled after some stainless steel versions available at Aircraft Spruce for $50. As usual, I welded this up out of 4130 steel. Wires will be wrapped in that orange silicone/fiberglass firesleeve material as they pass through the opening. A second sleeve will cover that on the firewall side, and be clamped to the white protrusion with a stainless hose clamp. More pictures to come when it's all finished.