The Idaho Howitzer is a baking soda and vinegar powered potato cannon (a.k.a., spud gun). Potato cannons are typically powered by combustible fuel (hairspray, ether, propane, etc.) or by compressed air. The Idaho Howitzer is powered by the chemical reaction when vinegar (acetic acid) and baking soda (sodium bicarbonate) produces water and carbon dioxide gas. The gas is contained within a reaction chamber and reaches between 20-30 psi. When the firing valve is opened, the gas is released, expelling the potato over 100 yards! (Our furthest shot so far is 435 feet.)

It was specially designed to participate in TechShop Detroit’s 2015 Maker Faire Detroit Build Contest. The idea was to design and build something on a 40” x 49” Harbor Freight utility trailer. The contestants were required to construct their entries at TechShop, between 6:00 pm, Friday, July 17 and midnight, Sunday, July 19 (54 hours). The entries were to be displayed at Maker Faire Detroit, Saturday and Sunday, July 25-26, 2015, with the general public voting for their favorite build. Winners were announced at TechShop Detroit’s open house, Saturday, August 1, 2015, where we gave live-fire demonstrations throughout the day.

Team Idaho Howitzer took First Place!
Build team:

Becca Frey, Trenton High School Junior
Jackie Frey, Grand Valley State Senior
Steve Frey, Inventor
Frey Innovations, LLC is a design and engineering services company. We are essentially  ‘Inventors for hire’. Our experiences range from coffee mugs to jet engines. What can we invent for you? Send email to