I made this bracket for a fan taken from an old Dell OptiPlex PC, but you can use any standard 120 mm fan.

This is a modular project and I plan to add more stuff in the future, like a filter holder for soldering fume extraction, a hand-held adapter, a stand, and other add-ons.

It’s powered by a 12 V battery made from three 18650 cells (3.7 V each), which I salvaged from a cheap Makita knockoff battery (“Makuta” 😄).

I wanted it to be rechargeable with basically any USB-C charger, so I used a USB-C module that outputs 5 V. The USB-C board is simply glued in place with hot glue. I could’ve used USB-C PD for 12 V, but I wanted it to work even with simple, non-smart chargers.
The 5 V is boosted to 12 V using a step-up converter. The step-up module is mounted with two M3 screws that go directly into the plastic (no heat-set inserts). The boosted 12 V then goes through a BMS for charging and protection.

The top cover (electronics and battery cover) uses four M4 heat-set threaded inserts.
Both the front and back of the fan (intake and exhaust) also use four M4 heat-set inserts each.