FYI... I'm learning 3D Printing concurrently with this project, so don't be surprised if the print quality isn't so great.  More likely the STL files quality, due to concurrently learning new software applications, aren't so great and you might find a 3D printer pen a way to seal up the gaps I've identified and am working on resolving in the next round of .stl and .gcode uploads.

Thinking like a Rust Oleum filler paint will seal up the prints well enough and maybe a small bead or even smear layer of silicone as a gasket will further seal mating surface leaks. 

The 3M connections will require the 3M rubber gasket. 

This is still a brain storming data dump in progress... so keep in mind anything used is at your own risk and am I no way liable for your decisions. 

Inspired by the Joshua De Lisle video and not the same design: 

You'll need the following for the welding design:

x1 - Wathai 5V USB 75mm x 30mm Turbine Centrifugal Blower Cooling Fan or equivalent

x1 - PWM motor controller or equivalent ~20V to 5V voltage regulator or step down circuit

x1 - Dewalt 20V Battery Holder and Trigger Assembly or 20V to 18V adapter 

x2 - 3M 6000/7000 series filters

x1 - CPAP BIBAP Tube or equivalent 

x2 - Kevlar Arm Sleeves or equivalent (fabric for covering CPAP hose & hood)

x1 - Full Face Snorkel or equivalent

x1 - Full Face Snorkel Adapter 3D printed (see STL or gcode files)

x1 - Blower Fan adapter (see STL or gcode files)

I'm also working on another design using the Uvex Bionic Face Shield.