tekhertz shares:

assembly –
glue the two parts together and load with Mentos (i glued them in as well), drill a 1/2 in hole centered in the bottle cap and spot glue the tray in place.

launch –
drink or dump a small amount of the diet coke so that the cap can be placed without the mentos touching the liquid.
screw cap on then flip the bottle turning the top away from you or any bystander and drop/ press forcefully down on the ground while releasing your grip.

download the files on: https://www.thingiverse.com/thing:4003377

Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!