3D printer spray coater

Why pay more? Ideally for my nanoparticle (or more specific to its main function nanowire) spray coater I needed 3 axis motion, a moderately heated stage, and the ability to turn on and off the spray stream. So, I bought a vellum K8200 3D printer , which takes care of both the 3 axis motion (note the x-y belt drives are much faster than the z lead screw, but z motion usually only happens before deposition so this is not an issue) and the heated bed. The thermocouple for the bed claims that the surface can reach 75 C which is more than enough to help whisk away the organic solvent holding the nanoparticle suspension, however the nature of spray coating, which is to force evaporation makes the bed cool down rapidly- perhaps a beefier heating element would be ideal. Finally, for controlling the spray I used an unused motor controller to simply give me a 5/0 high low output from the control board, which hits a relay to a solenoid valve, holding back about 35 psi of compressed dry air. Using the solenoid valve like this does have some ramp up/down effects on the spray stream, which cause me to start and stop the spray while the nozzle is not over my sample- a small concern on the lab scale, but something which can be mitigated if needed. Total cost ~$600, compare to getting a three axis system with flow control from a company like Fisnar, and you could be adding two zeros to that price!