Are we still talking about venting? I’ve been away for a while… But I really want to share this because I can’t believe how well it’s worked and how easy it was.
I have a 190 CFM fan that I’d bought to vent the office Glowforge, until the alternative filter finally arrived. Now that I have my own, my plan was to mount that on the inside of a piece of plywood I’d wedge in the window, and get everything sealed up perfectly so no smoke comes back in. But there wasn’t enough room for the fan inside and I couldn’t think of any reason not to put it outside… So, a visit to the hardware store later I’ve got a piece of OSB, some weather stripping, and a couple of cabinet handles. I cut the OSB to fit the window, cut a hole in it to fit the blower and beveled the hole with a drum sander on a drill to roughly match the shape of the blower. Also put the handles on the board, yes.
I wasn’t sure how I’d attach the blower to the board, though… I’d bought a couple of metal straps but they didn’t fit right. Next I thought I’d glue it on with caulk, solving both the sealing and the mounting problem at once, but I couldn’t find any caulk and I’m pretty sure I left my caulk gun behind in the move anyway. It eventually hit me that I can just tie the thing on. If I learned anything from my time on a tall ship, it’s that twine can do pretty much anything if you have the right knot. I put a gasket of weather stripping around the hole in the board, lashed the fan on, and put it in the window.
I clamped the (cheap aluminum) exhaust hose as tight as I could to the fan, plugged in the fan, and gave it a quick burn. No smoke. Gave it a longer burn and went outside to sniff. The blower throws the smoke so far away from the house there’s no way it’ll leak back inside. The Glowforge and the hose all the way to the outside are under negative pressure, so they’re more likely to leak in than out. The hose doesn’t need to be tight at all, I just slip it on. I’ve done around an hour of laser with this setup so far and haven’t caught a whiff of smoke until I pull the work piece out.
Moral of the story: Suck, don’t blow.
(And stop snickering, okay?)