This was constructed to be able to attach my 3M versaflo to my cheeper welding helmet without air intake.
Most likely this can be attached to other helemts as well.

You need:
Some silicone inbetween helemt and 3D printed parts
4x M3x20 plastic screws
1x M2.6x14 plactic screw (you can use another M3 but it will popup on the upper side)

On the printplate I also included a template for the holes that need to be made.
-Mark holes
-Cut oprening
-Drill 4mm holes
-Add silicone to Mid and Top parts
-Attach loosely in the backen first with 2 M3
-Attach airflow part with 2 M3 screws fully
-Attach front M2,6 screw fully
-Tighten back end screws

Best thing is also to make a chin-seal from cloth or thin leather. Not included in this.

Note: That this will never ever be as good performace as a real. But as a hobby welder this is better then nothing and better then trying to fit a mask under.

I have one Original Versaflo aggregate and one that I constructed my self (Don't think I will share that one…) . And no the one I did my self is not as good, but I can afford two…
Also I usally pop back anf forth from grindin mask to welding helemt so this is how I came about making this.