The #crbox in its temporarily assembled form. I've accidentally cleaned the air too well right now to test it.

It should draw about 500 mA @ 14V and clean about 300 cubic metres of air power hour. I hooked it up to a backup power supply and it shows that's it's drawing 0 Watts.

A 3m x 3 x 3 (10 x 10x10 foot old style units) room is 27 cubic metres. This means ten air changes per hour. One every six minutes. It probably won't perform at that level.

Each fan is about 10 dB they say and I could barely hear the box running. About 1m away, I'm reading 27dB with it running and about 23dB with it off.

Total cost = $34 Canadian dollars plus tax.
$10 filter
$24 fans (3x8)
The test was repurposed material.

What are you waiting for? Get building!

This is the #CRBox with the fan array in place. It was easy to drop in place with those handles. The power is wired in temporarily as I want to see how well the box works before I decide this power supply is right for the box. Then I'll cut off the huge plastic piece where the drill battery went from this repurposed power supply.

The final legs of my new #CRbox. This is the inside of the box. Now the strips of wood on the sides to hold the fan array in place while assembling.

@MichaelPorter Consider each multiple of 22 as one cigarette a day. So if the air is 88 in raw and you spent a day in it, that's the same as smoking four smokes.

Inside air is often at 35. That's maybe second hand smoke level and we know that causes cancer. Build a #crbox or two when you get home.

Public health no longer exists. We are on our own.

How do you make a #CRbox from a single filter? I cut it in two. That is a very careful operation depending on the tool you choose. Google for options.

Follow along as I make a #CRbox over the next few days. This is a new design of my own which uses a single Merv 13 filter from Costco. The filter is $10 but you have to buy four which is great for the classic #corsiRosenthalBox, but I'm going for a compact design for travel.

Hey #Ottawa, close your windows before going to bed. The smoke arrives over night and it looks bad. Like real bad. I hope you built a #CRBox or two.

I have had a #CorsiRosenthal box running for 24 hours. I moved the #PM2.5 sensor to an adjacent room from the #CRBox to see how well it can clean a room across the hall.

The low point on the graph is about 8 PPM and this is when the box moved to the bedroom. There was a fairly quick rise in one hour to about 12 ppm and then it slowly built to about 15 or 16 ppm over night.

After the moving the box back downstairs into an adjacent room, the level dropped to 10 ppm in less than an hour.

It seems that a CRBox does a decent job cleaning adjacent rooms.

3D Handyman - DIY Corsi-Rosenthal box fan air filters (5:26)
https://www.youtube.com/watch?v=lbWiZSsEqPg
* Cheap box fan + 20x20x1″ MERV14 6-pack + dowel legs = ~$100.
* Airflow Tests (# of Filters vs Cu-ft/min): 0=1200, 1=170, 4=490, 5=610
* 5-filter noise: 76 dB on high, 66dB on low.
* More filters is way better airflow, less motor strain.

https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box

HowTo image & alt-text
https://mastodon.social/@stevelieber/110505107582562610
https://meow.social/@stripey/110510248042368267

#CorsiRosenthalBox #CRBox #AirFilter #AirPurifier #Wildfire #Smoke #AirQuality

Just incase it could help someone deal with covid/smoke, Nordic Pure 20x30 high level filters are on a great sale on Amazon!
You can make a taller CRBox with these, and even add a 20x20 on the bottom for 20% more surface area.

Link: https://a.co/d/iM1OC7W

#NYC #smoke #airquality #crbox #CorsiRosenthalBox #cleanair #CovidIsNotOver

Controlled burning taking place around #meanjin #brisbane. Came home to a closed up house with pm2.5 sitting at 40ug/m3. Urgh. But it does give a chance to see the effect of my filters on the #indoorairquality #iaq. Down to 24 already … #corsirosenthalbox #crbox #smoke #pollution

I finally joined team #crbox this week after wanting to for months.

$85 CAD for the setup.
$42 for the fan, and the filters were about $36 (bought in a 12 pack for $110).

Merv13 filters, so while it’s not up to hepa filter standards, it’s pretty dang effective.

Quieter than my fancy Mila air purifier, and way way cheaper (it was around $500 CAD, I think).

If anyone near Hamilton, ON wants to make one, I’ve got some filters you can take at cost.
#hamont #CovidIsAirborn

Ok, I did it, I reassembled my C-R Box, tossing out the old merv-13 filters and replacing with new filters (every 6 months is what I have noted) It wasn't super dirty, but I'd recommend wearing a mask). It took about 20 minutes, even easier than the first time because I knew to point arrows inward, and I reused the cardboard bottom and shroud triangles for the top. Don't forget to tag it with the new expiration date! #crbox #CleanAir #COVID19

My latest article covers the topic of #3Dprinting a prototype air purifier from a #DIY design. The journey towards developing a cheap efficient air purifier has brought many lessons.

The #CRBox air purifier design is more of a project than a product, with a duct-tape aesthetic but delivers on performance and cost savings. Using open-source technology and #Blender3D, we aimed to create a visually stunning air purifier. https://airsupportproject.com/can-you-3d-print-an-air-purifier/

Resources that may be helpful for people.

This includes a layout for a scale image of an Arctic P14 fan (1 mm = 1 pixel in the image), which can be useful for designing home air filters and #CorsiRosenthalBox #CRBox. The image can be printed as part of designs and cut through (like a stencil.)

You can find resources and research related to all of this here -- feel free to revise/comment as well:

https://docs.google.com/spreadsheets/d/1LsInC4b7qNGPXaQYLBJVUfiC2Ko_MrlmpLXkctHObhM/edit?usp=sharing

I finished a prototype virus grade air purifier: It cleans 475 cubic metres per hour, uses ten watts of power, and is 25 dB running at full speed. About $75. It is about 25 by 16 by 6 in archaic units.

The next one will cost more because I won't make it out of cardboard. The cardboard is nice because you just throw the whole thing out when the filters are dirty and the entire thing is pretty light although it is also quite stable.

I am happy to share the details if clean air is important to you.

#crbox #covid

A type of synthetic chemical found in a range of products including cleaners, textiles, and wire insulation, decreased by 40% to 60%; phthalates, commonly found in building materials and personal care products, were reduced by 30% to 60% by the #CRBox.

#EpiVerse
https://www.futurity.org/corsi-rosenthal-boxes-air-pollutants-2849372-2/

@syntagmatic Wow!! What a neat idea to illuminate and suspend it from the ceiling!
@Jimrosenthal4 have you seen this?
#CRBox

#CRBox

Assembled the rest of the #CRBox sound-baffle shroud two days ago. Holding up well.

US$20 in paint stirrers and amac boxes. Plus some bulldog clips, duct tape, Dual Lock tape & packaging tape (for cardboard overhangs).

Now to find some time to obtain and experiment with some audio analysis software to get some benchmarks as to just which frequencies of noise is actually dampening…

Also, want to get some shelves to raise this assembly up a bit higher and reclaim table-space.

#CovidIsAirborne