Ideas for venting

I’d be more leery of a spark, that stuff is combustible.

“A FLAMMABLE LIQUID like gasoline, lacquer thinner, alcohol, some paint thinners, etc. are much more volatile — their vapors can ignite below 100° F, even down to freezing and below.”

“Paint thinners at high levels can also be a fire/explosive hazard. I recall one instance where two workers were cleaning the floor of the plant on a Saturday morning of sticky resin by pouring paint thinner on the floor. They took a thirty-minute break to let the paint thinner soak in and loosen up the resin. When they returned to work, they used a metal scrapper. It caused a spark resulting in a vapor explosion. By the time the sprinklers activated, it was too late. Neither man survived.”

I did a quick search on Amazon for bathroom vent fans, and the largest I saw was rated at 400 cfm. Let’s say your basement is 20’ x 20’ with an 8’ ceiling. This means that optimally this fan would change the air out once every eight minutes. With the length of the piping you want to run I would expect the actual cfm to be quite a bit less. I might be wrong but that doesn’t seem like enough air flow.

A couple of other things. You said that opening the window when it was 12 deg out was not an option, but if you have an exhaust fan blowing to outside there has to be air coming in from somewhere. If your house is very well sealed, it might even be necessary to crack the window a bit to allow make up air.

There are also a few safety concerns. One is the possibility that some of the finishes you want to use might be flammable and won’t mix well with the open motor design in some bathroom vent fans.

You are trying to create negative air pressure in your basement to keep the fumes from going upstairs. This can be complicated by what type of heating system you have. Sucking combustion gases back into the basement while blowing fumes out could be deadly. -Jack

Beyond an expensive venting system, I could only suggest using the non-volatile and
human friendly finishes that are widely available .