The chamber is 3 inch to 1.5 inch reducing cleanout wye with a cap on the bottom and the wye. I used a flush bushing to 1.5 inch threaded. The barrel is 36 inches with a male thread adapter. I could have just used a reducer to go from the chamber to the barrel, but I wanted have the ablility to change barrels out.
The wye is useful because I don't really tote the gun around and sitting on my deck shooting stuff into the woods, it's more convenient to load the fuel into the cleanout than from the bottom.
The ignition system is a BBQ replacement unit housed in a 3/4 inch Tee, which I epoxied to the side prior to paint. I used a rotary tool to remove material from the Tee so it fit snugly against the combustion chamber. The wires were finished with spades because I want to move the igniter between projects as I'm experimenting. I used stainless steel bolts threaded through the chamber body creating a 1/4 inch spark gap. After testing the spark, I cut off the bold heads so I could use the wing nuts.
The image is cut from thin sheet aluminum and epoxied to the body.
