Building a small fume hood for stinky projects

Step 8 Set up the exhaust vent

The last thing needed is somewhere to exhaust the fumes to. Ideally the fumes should go up a stack and exhaust high up so that no-one on ground level is exposed to it. The choices you have here depend on your particular location. In our house we have a couple of options: steal the dryer vent, tap into our chimney via an access door, tap into the furnace exhaust, or just have it blow out a window. It would probably be possible to tap into the sewer vent as well, but that would require a lot more work. We decided to go up the chimney through the access door.

To mate the round duct with the square access door, I made a bulkhead out of sheet plastic. The piece needs to be at least the size of the opening, and it's a good idea to leave a bit of overlap. Trace a circle around the duct and cut it out just a bit smaller with an utility knife. Carefully guide the end of the duct through the hole and seal/hold it together with tape. Stretch the duct some now before attaching it to the wall, so that you won't need to pull on the connection later. Tape the bulkhead to the opening in the chimney and make sure it's good and sealed. In my case the tape did not stick well to the painted concrete of my chimney, so I had to wrap it around a corner.

Once that's done, secure and seal the other end of the duct to the boot on the hood. Testing time!