I have to use noxious chemicals, sometimes. Usually, the amounts are small and the substances not too terrifying–a few drops of toluene-based resin for making a permanent slide, for instance. When I need to use something especially nasty, I try to work outside. But that’s not always practical, of course.
A few months ago, I had to mix up a potion for preserving some amoeba DNA. It had to be done in a reasonably clean space, without a lot of contaminants flying around, and the recipe called for ingredients (Sarkosyl and EDTA) that you don’t really want to breathe in. I do have access to a properly equipped laboratory, but it’s half an hour from here. I decided it was time to make a little homebrew fume hood.
My space is not very big–just 10′ X 11′–so, the box had to be light enough to lift up to my work surface, and small enough to tuck away when I was done. I had some 5/8″ plywood, an in-duct ventilator fan, and a free morning. At a local hardware store I picked up some 4″ flexible dryer hose, a sheet of acrylic and a few battery powered lights. With those, I made this:
The dimensions work pretty well, for me. The box is 26″ high, 28″ wide and 18″ deep. The plywood is just glued and screwed together (no joinery or special hardware). The acrylic sheet slides up and down in a groove on the front facing, built up from a few pieces of scrapwood with spacers. It couldn’t be simpler.
At some point, I’ll line the interior with some stainless steel sheets, which will make it safer to deal with any spills that might occur. Apart from that, I’m satisfied with this solution, for now.
Ventilation is provided by an inline duct fan (a Cloudline AC Infinity 4″). It’s an inexpensive fan with a sparkless EC motor. It has adjustable speed settings, and my tests show low turbulence and good airflow in this small work space. For now, the ducting is plastic, which is not ideal (it’s what they had at the store). It’s fine for small tasks, but would probably degrade quickly if I were working with certain solvents. I’ll upgrade to aluminum when I have a chance.
The “distal end” of the ducting is fitted to a panel that sits neatly in the frame where the window screen usually sits.
When I’m done working, I stow the box on the opposite wall, next to my little lab fridge.
And that’s it: my janky, jury-rigged fume hood. It works well enough for my limited purposes. That said, I’m not recommending that anyone else build one of these. The tagline of this blog is “Do-it-yourself Protistology,” and this is just an example of me, doing it myself. I’m sure I don’t have to point out that this thing is not built to the standards required at a professional facility. 😁
