Materials: - 4L sealed box made from PP - HDD motor from old 3.5" 250GB WD drive - Model aircraft ESC for brushless motors, you may use almost any model, i used Turnigy 20A - 12V PSU, 10W is enough (1A) - Servo tester, i made one from ESP simply because i don't found pot in components box :)
Motor plate designed in FreeCAD. Impeller is modified version of [Centrifugal impeller](https://www.thingiverse.com/thing:259773), unfortunately i lost source, but modifications are easy - holes to tightly fit on motor outer dia.
To assembly you need cut hole for motor and drill 4+3 holes for M3 screws, then apply silicone sealant and tight screws. Then check impeller, i used disc spacer ring to mount w/o disbalance. Then solder ESC wires to motor, there should be 3-phases and (possible) central output, use ohmmeter to find phases (mine have 4 Ohm phase-phase, 2 Ohm phase-center). Check rotation direction, if it wrong you may change ESC settings (if it supports) or swap any 2 phases. When all tested to be working i sealed wires with ABS juice (plastic in acetone) and glued impeller with thread lock.
ESP8266 is not required, just i don't have free servo tester, so i made one with MQTT control :) It connects to MQTT broker (mosquitto), then using [MQTT Dash](https://play.google.com/store/apps/details?id=net.routix.mqttdash) i may control PWM value. "Smart" vapor bath :)
Benefits from HDD motor - it is sealed (use less acetone, no losses via motor hole), and it is **very quiet**!
Also i use spear stand for a while, it is useful, but require strong metal backplate.
Place pice of cloth to bottom, it helps to evaporate faster.