Foam Cannon

From Fusselman.org

For Ron's "Back to School" bash (no, no one going to the party is going "back to school"), he wants to have a huge foam gun, to spray suds everywhere. Personally, I think he came up with this just to torment me. Anyhow, given that the party is in like 2 weeks, I figured I'd best get started on said cannon.

Failed Idea 1: Pressurized Hand Soap Dispenser

My first thought was to base it (somehow) on a foaming hand soap dispenser. They're pretty straight forward. It's a container full of liquid, with a pump. You pump the pump, and it converts liquid to mounds of glorious foam. My plan was to use one or more dispensers to generate the foam, and then a blower to throw it. I figured one could get the dispenser to make foam simply by pressurizing the liquid vessel. (For reference, I was running 20psi off the compressor, with the valve about half-opened on the blowgun)

I was wrong. With the pump in the fully "out" (relaxed) position, the vessel just built pressure, but nothing came out the nozzle. In retrospect, this feature is what prevents the pump from leaking in storage. As I depressed the pump, the system started to flow. Unfortunately, it was flowing clear liquid, not foam as I'd hoped. FAILED.

I'd like to note that I can't take total credit for this idea. This article, while mostly unrelated, was really what inspired me.