Why the potato cannon required modification after all this time.

I'm sure over the near-decade since it was first conceived I've brought it up in conversation more than I've brought it out for use- a sad fact. And I think the reason for the low usage is it's cumbersome prep/load/launch/clean/repeat procedure. I'll start with the loading.

After testing several aerosol fuels my co-conspirator and I selected "original scent" Right Gaurd brand aerosol deodorant as the most suitable fuel. the "pros": it wouldn't degrade the PVC or joint cement of the cannons main structure like some more flammable fuels. It was cheap, plentiful and reasonably effective. And, in contrast to the more popular hair spray which leaves a sticky residue, the deodorant leaves a fresh, powdery residue that cleans up easily. The "cons": in Right Guard at least half of what comes out of the nozzle isn't flammable. Only the propellant is, none of the propelled product is. So although it requires few dollars to acquire there isn't much "fuel" in it. Another drawback is mixture control. It's all guess work. And, in order to get the spray in there the rear service cap must be removed and quickly replaced and secured before it can be fired. A two person job most of the time.

The launching. This had not been so bad in light of the fueling, but a barbecue ignitor dangling from it's wires; that's just sloppy.  

So the new design parameter list:
-eliminate the need to remove the rear cap other than cleaning and service
-find some alternate fuel. cleaner, more effective, easier to use, easier to control.
-a secure, ergonomic mount for the ingnitor button

Some additional maintenance items to address while I'm at it include replacing the four "spark bolts" and associated hardware, cleaning the chamber in preparation for paint sometime in the not-too-distant future, rework the wiring for the ignitor for a cleaner, more professional look.

What fuel then? Well propane of course! :D I had already decided on this not long ago and began collecting components for the metering and delivery system. After pulling them all out again to revive the project I went directly to my design method: simultaneous hardcore research, brainstorm/daydream, simplification (for budgeting constraints) and "finding the missing puzzle pieces."

More details to come!