The 3-2 combustion is my favorite gun right now. I usually fire it off of aquanet hairspay but i am going to test nitrogen (n2o), and propane. The only one i have tested so far is the aquanet hairspray, mapgas, wd-40, and right guard spray deoderant, and maybe a few others. Right now i recommend aquanet.
What You Need
(Note all parts are pvc)
-1 one foot piece of 3" pvc
-1 four foot piece of 2" pvc
-3"-2" bell reducer
-3" coupler
-3" female adapter
-3" threaded endcap
-lantern lighter
-pvc glue (note use pvc glus on pvc parts and abs on abs)
What Tou Do
Take the 1 foot piece of 3" pvc and glue the 3" coupler on one end of it. Now glue the 3" female adapter into the 3" coupler. Next glue the 3" to 2" bell reducer onto the end of the 3" pipe that doesnt have any thing on it then glue the 4' piece of 2" pvc into the 2" side of the bell reducer. For the end cap drill a hole in the center and put the lantern lighter in the end.
Firing Instructions
Load the projectile down the barrel.Now take you fuel auqa net hairspray right guard deoderant ect. into the combustion chamber then skrew on the endcap, flick the lantern lighter and hopefully hear a BANG!!!! and a potato going through the air.