Corsi-Rosenthal Box For Ambient Dust

[redsquid2]

During the pandemic, two engineers developed a cheap, high volume air filter that you can build yourself with the following materials:

1. A box fan.
2. Some cardboard.
3. Duct tape
4. Four panel style air filters. In the demonstration linked below, Dr. Corsi uses MERV 13 filters, which can filter out very fine particles. I assume they are more pricey than filters of a MERV 5 or MERV 8 rating.

After watching three different people build three different Corsi boxes, I would estimate it takes one hour at the most to build it, depending on interruptions from dogs, cats, children, and/or spouses.

One thing I noticed while watching demonstration videos is that the Corsi-Rosenthal box looks quite flammable. So it would have to be used in a place where there is no chance of a flame or spark getting near it.

Here is the link: https://engineering.ucdavis.edu/news/science-action-how-build-corsi-rosenthal-box

I haven't made one yet, and while we do have a HEPA filter in the living room, we also have two house rabbits and a cat, so...I think one of these boxes for the house hold, and another for the shop would be a good idea. A Corsi box in the living room with MERV 5 filters would go a long way toward exterminating the prolific dust bunnies, and would probably add life to the HEPA filter. Another Corsi box in the shop would reduce the dust that settles on every surface.

 

[Bühlmann]

I built one of these about 6 months ago for use in my shop. Cheap & effective, plus it doesn't make a ton of noise. I use a JET canister dust collector when I'm sawing or grinding and that makes a huge difference in shop air quality, but the 4-filter + box fan air cleaner is an excellent supplemental device. I also like to place it near me when hand sanding, and it picks up a lot.

I've vacuumed off the outsides of my filters a few times since I built it. I can tell that I won't be able to do that too many more times until the filter media will fail, but the filters are cheap & easy to replace.

 

[Ken H>]

That is slick and an easy build. Thanks for the link.

 

[Stacy E. Apelt - Bladesmith]

That is a very old idea. Many of us had a box fan with AC filters taped on as our first air filter. Problem is, they are not real efficient for our dust types. You really need an exhaust filter system or a separator/recovery system like a cyclone.

 

[12345678910]

Bussee had an article in a woodworking magazine decades ago with that.

Only one filter though.
These guys have made it into four filters for more surface area.

 

[Stacy E. Apelt - Bladesmith]

Another issue with a box fan system is the airflow volume. While any amount of filtration is a good thing, once restricted by the filters, the box fan has a pretty low flow rate. The commercial hanging fans (they can just be set on a cart near where you work) are engineered to have a good flow volume.
Whatever you choose, vacuum it out regularly or it won't do anything.

 

[A.McPherson]

I think the interesting thing about this one is that they suck the air through the filter rather than blow it through.

I wonder if it gets better flow rates because of that...

 

[Bühlmann]

It gets better volume of air flow because it is has 4x the filter surface area of the simple box fan air filter Stacy was referring to. That means the fan more air for a longer period of time before capacity is reduced by filter clogging.