Air Filter for Engraver Isolation Box

Overbuilt DIY Air Filter for Enclosures

Whether you're filtering out laser engraver fumes, solder smoke, or mystery haze from whatever that last print was made of, this DIY air filter is built to take it. Designed for enclosed spaces like isolation boxes, this unit uses real HEPA filtration and activated carbon, and moves a surprising amount of air thanks to dual-fan assist. It’s overbuilt on purpose—because less maintenance = more time for actual projects.

✅ Features:

• Mounts two 80mm square fans side-by-side (designed for 10mm thick, but fans of any thickness will work—just expect them to be recessed or protrude slightly).
• Holds four Nispira DSTx 2.0 HEPA filters (3.35" L × 2" W × 0.38" T)
  Amazon links:
  • 3-pack
  • 6-pack
  • 12-pack
• Carbon chamber is dumpable and refillable
  Remove one or both fans to dump the used carbon, then pour in fresh pellets through the exhaust ports. The chamber holds a decent amount—up to 1.25 Liters or ~0.6Kg—which means fewer swaps over time (yeah, the exchange is a little annoying… that’s why I gave it an over-sized capacity).
• Internal pellet grates with 2mm-wide slots keep media suspended above the filters and prevent clogging, while still allowing full airflow.
• Fans vent upward, pulling air from below through the pre-filter, HEPA filters, carbon bed, and then out the top.

🛠 What You’ll Need:

• 2× 80mm fans (any thickness; 10mm fits flush)
• 4× Nispira DSTx 2.0 HEPA filters
• Pre-filter sheet (any cuttable sheet filter or mesh)
• Activated carbon (Pellets are preferred)
• Hot glue for filter mounting
• 1× rubber band to hold the pre-filter in place
• (Recommended) 8× M4 heat-set inserts, 8 washers, and 8 M4 screws to securely mount both fans
• Whatever wiring setup suits your vibe—USB, 12V rail with a buck converter, relay switch, microcontroller, battery pack… up to you.

🔌 Power & Fan Notes:

My personal setup uses 5V fans powered via USB, but this design will work just fine regardless; Run whatever voltage fans you like (or happen to have on-hand), just match the power source accordingly.  It's your build, it's your choice; If you're the type to take on this project, odds are you're smart enough that I don't need to hold your hand.

🧪 On Filters and Carbon:

• If you find other filters that match the 3.35" × 2" footprint and are glue-friendly, give them a try—and if you test alternatives, PLEASE consider sharing your results, both good and bad.
• I used 4mm extruded pellets, but anything over 2mm in size shouldn't be a problem — I would avoid crushed/crumbled/granular types, but if it's all you can find/get, then PLEASE sift out small pieces first to prevent clogging.  Pellets are preferred due to it's better consistency with size, shape, and subsequently more evenly distributed airflow, but use what you prefer/have access to.
• The carbon chamber is serviced by removing one or both fans and dumping/pouring through the dual-purpose exhaust holes. It’s not the fastest thing to change, but you won’t have to do it often thanks to the oversized chamber.