Back in my boat building days I periodically had the need to spray some very toxic paints. A fresh air supply is highly recommended for these occasions but they are very expensive for infrequent use. I found this today as I was doing a deep spring turf-out of my shop and thought it might save someone a few bucks.
This is what I came up with to save my lungs without the cash outlay for a compressor operated one with filters and coolers. (The filters and coolers are to remove the oil and heat that the compressor adds to the fresh air it takes in.)
Photo #1 shows the heart of the “system”, a cheap bathroom exhaust fan. In this case it is attached to a plywood disc.
Photo #2 shows the same thing from the back with a length of 3" dryer vent hose attached.
Photo #3 is one of the back doors of my current shop. The portlight is plexiglass and can be unscrewed and replaced by the plywood fan mount.
The last one shows a two filter respirator with the other end of the hose attached. The other side of the respirator is sealed off by simply putting a piece of plastic film over the base and then screwing the filter in.
This is the system that I used to paint Friendship with nasty linear polyurethane paint. In practice it works very well. The large bore hose is a little more trouble than a small pressurized one would be but it is very light and not much of a problem at all.
When you turn on the fan the respirator is filled with fresh, cool outside air with just a slight positive pressure. Excess air goes out through the exhale valve (and any minor leaks in the seal) and there is no way any ambient (poisonous) air is getting in. The air in the shop may be thick with nasty solvents and overspray but you are smelling the daises outside the door. Of course there are other concerns such as eyes and skin contact that also have to be dealt with but this one will keep your lungs safe and happy.
The total cost, aside from the respirator which you should already have if you spray paint, is about $30.
I’ve always mounted them in some exterior surface like a door panel but it would work just as well if you just took it several feet outside the door and left it on the ground.
Thanks for looking in.
-- The early bird gets the worm but its the second mouse that gets the cheese.