Build a Cheap Air Filter

Air by itself contains many contaminants. Not to mention the contaminants that enter the air when working with wood, paint, solvents and any materials. But not all hope is lost, having an air filter to remove those particles from the air can improve the air you breath. It’s super easy to build a cheap air filter, easier than you may think.

Some air filters can be very expensive. For me, I need to filter the air from a make shift paint booth that I am building for a couple projects. I just need some cheap air filters to do the job. So I took two box fans, a little bit of wood and some 20 inch X 20 inch air conditioner filters and built two of these guys. Watch the below video to see how.

Modifying these box fans isn’t necessary if you have a box fan like this:

The problem with this particular box fan is that it is a bit more expensive, quite a bit. At $45 each, you could make 3 of the $15¬†fans, which each would probably work better in the end anyhow. The particular issue with the fans that I have are the placement of the switch and plug. I had these two fans for about 4 years now, so I didn’t really think about the placement of these elements when I bought them, so I need to deal with them now. You may want to think about buying fans that you wouldn’t need to modify this extensively if you don’t already have them.
I came up with a few goals for these fans. First, I wanted to utilize the original box fan housings. But the switch and plug were on the back of the motor which made it difficult to turn on and off as well as being in the way of the filter. So I wanted to move those to the outside of the fan housing.

Next, I wanted to optimize airflow through the fan because the filter causes some resistance on the intake side of the fan, which caused air to be sucked in from the front outer corners of the fan. Finally, I wanted to create bracketry that would make it easy to replace filters.

Disclaimer: If you are not familiar with electronics or making modifications like these, please consult an expert. If you solder as I do, be sure to have adequate ventilation. Also, make sure to use proper procedures and wear your protective equipment when using any tools.

If you’re stuck with the same fans I have and you are going to move the switch and plug as I do here, you don’t necessarily need to solder the connections. You can also use these:¬†or:

For the brackets I thought about the design and although I am not going to do it to mine since the brackets I made work, I suggest you go this route.

Box Fan Bracket

Leave a Reply

Your email address will not be published. Required fields are marked *