Laser Fume Scrubber - Fume Coffin Redux

thingiverse

VERY IMPORTANT: This device is designed to reduce or eliminate fumes and particles from the exhaust of a laser cutter, but it does not make the air safe to breathe inside a room. You must vent out a window. This is extremely crucial. The device itself cannot guarantee safe breathing conditions inside a room. Venting inside a room with this device will likely cause serious health issues or even death. Is that clear enough? ALSO VERY IMPORTANT: The blower fan should be placed after (on the outlet side of) the fume scrubber, and it pulls air through it. The Venturi effect means that any holes or leaks in the box will simply pull clean room air into the box. If you were to put the blower fan on the inlet side and push air through the box, any leaks would cause fumes to be pushed out of the box, into the room and then your lungs - this is extremely hazardous!! The air flow direction is: laser > prefilter > HEPA filter > Carbon Filter > Blower fan > window. The pre-filter (Honeywell HRF-APP1) wraps around the outside of the HEPA filter (Honeywell 24000 style). The carbon filter I used is a VIVOSUN 4316274413. I am using a 460 CFM blower fan (Tjernlund M-6) with 6-inch to 4-inch step down adapters, since I'm using 4 inch dust collector hose (Fulton 4" "Ultra Flex Clear-Vue Heavy Duty PVC Hose"). I have a Boss 1420 laser; if your laser is bigger than that or has different airflow requirements, you might need to adjust accordingly. The actual airflow of the fan will be affected by the filters and the hose diameter, so mine definitely has less than 460CFM. Sorry, not too much explanation here. This project requires some common sense and adjustments as needed. I used 1/4 inch plywood and square cut 1x2 (nominal) pine for the frame inside. Check out the Fume Coffin project on Instructables, this is an evolution of that design. Note that the Fusion file has 1/2 inch plywood. If you use 1/4 inch plywood, you will need to adjust the dimensions. The cut lists shows essentially what my dimensions were, but I only used them as a guideline. Sorry for being vague. You should be able to figure out how to make this if you read the fume coffin Instructable. I just re-oriented the filters so that the HEPA filters from outside to inside, this also allowed me to put the carbon filter inside of the HEPA filter. You need to 3D print two of the 4 inch bulkhead fittings and one carbon canister adapter, or figure out your own way of getting the vent hoses into and out of the fume scrubber. I used 4 inch dust extractor hoses, made for woodworking. The inside seams are all sealed with silcone based caulk. The end caps are removable so you can change pre-filters (frequently) and filters (less frequently - as needed). End caps and main HEPA filter are sealed with rubber foam weather seal from the hardware store. This will remain a work in progress, but I do not intend to add further details or edit the files to be more clear. I hope this helps someone, but I didn't ever intend to share this, so I didn't document well. Original design: https://www.instructables.com/id/Fume-Coffin-Laser-Cutter-Exhaust-Vent-Filter/