The CNC frame is one of those cheap kits that you can get on ebay for instance. Mine was around 200 euros, and it is actually a good value for the price. I built the kit and then replaced the electronic controller with an STM32F469 discovery board and an arduino CNC shield.
For the sandblaster itself, my father and I hacked this simple solution made from a soda bottle and pipes/fittings that you can find in any hardware store.
The sand is falling from the tank in a small tube mostly thanks to gravity. The sand tank still needs to be pressurized to avoid air coming up from the nozzle.
The sandblaster was then mounted to the CNC frame where the engraving spindle is supposed to be, and the sand tank is somewhat fixed above the machine. As you can shortly see on the video, I’m controlling the airflow manually as I didn’t have a solenoid valve to make the machine fully autonomous
On the software side I re-used my Ada Gcode controller from a previous project. I still wanted to add something to it, so this time I used a board with a touch screen to create a simple control interface.
This machine is actually not very practical. The 1.5 liter soda bottle holds barely enough sand to write 3 letters and the dust going everywhere will jam the machine after a few minutes of use. But this was a fun project nonetheless!
PS: Thank you dad for letting me use your workshop once again ;)