Darkroom Duster
I have had a small bottle of Nitrogen rolling around on the garage shelf for a decade or so and decided to put it to good use.
I obtained a bottle bracket, new (read clean) regulator, Filter Assembly and Nozzle.
The brackets were easier to obtain than to build, the buckle is actually pretty good with gripper teeth, I just used a long pair of pliers to tighten the strap, kinda like a Spam can key. The filter is an inline type made to be used on paint spray guns. Supposedly 5 micron...
The brackets were screwed to the underside of the enlarger table which is topped with a solid core wooden door. The placement is with the knob and regulator about 2" back from the front of the table top. A hanger eye and an admonishment to turn off the mail bottle valve have been added.
I used Fusion 360 to design a bracket to support the bottle at the regulator to get rid of the remaining wobble caused by straps that allow a little bit of movement. This was 3D printed using PETG. The last photo is the final installation that now includes the bracket as well as a nicer hook to hang the nozzle from.