Mentos-Diet Coke Cannon

thingiverse

I have seen demonstrations of the Mentos-Diet Coke (now with Coke Zero also) at the Maker Faire in San Mateo CA and always wanted to try it out. http://www.youtube.com/watch?v=hKoB0MHVBvM . Eepbird's early work. This is the video with the cannon pictured here with the round top http://www.youtube.com/watch?v=6PLzzKISAuI Here is a printable version that screws on top of the 2 liter Coke bottle to hold the ammunition (Mentos). Install the safety pin once ( the ideia is that it once recoiled to the firing position it will block some exit of coke through the side hole as can be seen in the pictures). Just push it in to reload in other bottle. You can also improve the seal using an O-ring (~26 mm external diameter and ~4 mm ring diameter) or even a garden hose rubber washer. For the video the cannon did not have an O-ring. There are 4 choices of spray: round, flat, cross and V. The round and V work best. The SketchUp file is attached for further editing and modifications. I printed the tops in orange to be able to find them easily in case they flew out. Printing the whole set together saves time but leaves a lot of little holes on the parts as the nozzles moves to the next victim. There is probably something in SF35 to handle it but I did not try it. I have attached the separate STL's for those perfectionists out there. Instructions Printing the plate with 100% fill and 0 extra shells (coke will get inside it at 40% fill). Adjust (file with a round file or rolled-up piece of sand paper) the top opening (the part that is the bottom at the printer) to provide a tight fit for the spray caps. It has to require force or they will come off with the pressure. Press the chosen top on to the cannon Load the ammunition - 4 Mentos for a 2 liter bottle. Push pin in place. Screw the cannon on the bottle carefully so you do not fire it while doing. I put a few turns of the string around cannon clockwise before screwing it in place so the risk of misfire is reduced. Move to a safe distance, pull the pin up to the stop (do not pull to hard or it will point right at you :P ) and watch your handy work.