In this post I’ll wrap up my account of constructing the holzgas system grafted onto an ex-French, ex-German Citroen 11CV sedan. I have written before about my habit of making use of “found” materials whenever possible. The big reveal here is that . . . wait for it . . . major parts of the system on the car were sourced from a used COVID-19 home test kit!

The item on the left in the photo above is the plastic tube into which the test strip is placed to determine a positive or negative reading from the COVID test nasal swab. Before I painted the tube I wrapped a couple strips of painter’s tape around it, to simulate retaining bands I’d seen on photos of holzgas precipitating tanks; I closed up the tube’s end and added items from the “leftover parts box” that bring to mind typical fixtures seen on the tanks.

In the foreground is the gas cooler, a component that is typically mounted on the front of vehicles. I constructed the cooler from “leftovers” that resembled a radiator, whose function the cooler replicates.

And what about the test kit swab? Nipping off the swab itself left a sturdy, hollow tube whose diameter replicated the pipes that delivered gas from the precipitating tank to the engine, where it was burned to propel the vehicle.

The second picture shows the lengths of tubing that link the tank to the engine. Also visible are the holes I bored into the Citroen’s fenders (“wings” to folks that prefer British automobile nomenclature), through which I threaded the delivery tubes.

The next post will be concerned with the Citroen’s final assembly and painting details. I’d appreciate knowing what readers think about this project. Thanks!