I have wanted one of these since I saw Alec Steele wear one while grinding. Unfortunately the 1300 dollar price tag was well out side my range for nothing more than a huge improvement in my comfort level while grinding, cutting, or sanding. I have worn safety googles and a 30 dollar mask for a long time and they work ok. I mostly disliked breathing in my own lung juices and having the glasses fog up all the time. Now I don't have this problem. The most costly thing in this build is the used CPAP machine. Other than that, you may have some of this laying about. If not I estimate it would cost 400 bucks at most...That is assuming you have a 3d printer. All the step files and stl files are up on thingiverse for you to change as you need in order to get it to work with your CPAP blower or other fan. The arduino code is also located there. I hope you enjoy and I am sure you will see more of this mask in the weeks and moths to come as I work on some planters for the wife, and start trying my hand at rotary carving.

Thingiverse:
https://www.thingiverse.com/thing:3806256

Alec Steele Channel: https://www.youtube.com/user/alectheblacksmith

Bobby Duke Channel:
https://www.youtube.com/user/DukeWoodcarving