reminder.... "Remind me to take a photograph of it and post it here. "

I just go approved for medical on my cpap, so now I can compare the DIY I 'm making w/ the one I will get fitted with.  

I ordered a mask:

https://www.amazon.com/gp/product/B079F69D88/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

and (erroneously) a fan that barely meets the specs just to evaluate: 

 https://www.amazon.com/gp/product/B01CSNEO2G/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Brushless Radial Blower - UTUO DUAL Ball Bearing High Speed 12V DC Centrifugal Fan with XH-2.5 Plug 120mm by 120mm by 32mm (4.72x4.72x1.26 inch)

From Wikipedia: The pressure required by most patients with sleep apnea ranges between 6 and 14 cmH2O. A typical CPAP machine can deliver pressures between 4 and 20 cmH2O. More specialised units can deliver pressures up to 25 or 30 cmH2O. CPAP treatment can be highly effective in treatment of obstructive sleep apnea.

The motor 

• Max. Air Flow: 42.45CFM
• Max. Static Pressure: 41.10mm-H2O ( oops I though it was in cm-h20 )

The real cpap motors look to be similar to RC motors and ESC's. Should be easily 3d printed:

-Lee