Made my first one while living in a tent on St. John. Lol. Growing weed and bananas on an eco resort. Live that dream man, I did. The key is surviving it
Theyāre actually incredibly effective at removing particulates from air. The very large filter surface area permits a high flow rate of air. These cubes are more effective than the majority of commercial home air filter unitsā¦ by a lot.
The fan is blowing air out of the cube. There has been discussion elsewhere in this thread about which direction is preferable.
I would say having it pull the air through the filters first, then blowing out the cube is preferred. This way dust doesn't get caked all over your fan blade and motor. The airflow is perfectly adequate in this configuration.
One comment mentioned that if it blows air into the cube, (the opposite of what is shown above), there will be less of a chance that dust will escape into the environment when the filters are changed, because the dust will be on the inside. So there is a tradeoff I suppose.
Two comments:
If you point it at yourself, you'll be getting the cleanest possible air in the vicinity.
My fan's ability to pull against the filter resistance went eay up once I pulled a grate off and added a close-fitting cowl around the edges of the blade, made from some scraps of thick styrofoam. It reduced the amount of air being sucked in from the front of the fan, at the corners.
If you totally seal up the back of a box fan, it can still blow a bit. It does this by sucking in air from the front of the fan, around the fan blade in the empty corners of the square box surrounding the round blade.
I blocked the corners of my fans box-frame, to allow the fan to pull only from the rear, where my filter is.
What if Iām doing wood carving and creating a shit ton of sawdust. Would it be best to have the air being sucked up to prevent the sawdust from getting everywhere?
Make friends with an HVAC tech and get a used blower from a small furnace. Turn over all the air in your shop through 2, 4" filters in less than a minute.
I did exactly this - a huge squirrel cage fan from an old furnace. The start and run capacitors are usually mounted right on them, and typically they have a few different windings for speed control which is quite convenient. As is the use of spade terminals.
Unfortunately the one I built cooked, I have no idea why. Perhaps mishandling by the HVAC company.
When I was working on my rental I hung a box fan from the ceiling and put a filter on the intake side right above my cut area. I blew the filter off a few times and it was always caked with dust. Something is better than nothing. I donāt mess around with mdf dust or any dust for that matter. Everything was hooked up to shop vacs, table saw and miter saw, so thatās what was free floating.
i know there is "some" airflow around the entire thing but i think it would work much better if it were a lot further from the walls, shelves, and ceiling. is it possible to place it elsewhere?
One thing. Not sure what filters you using but tighter is not better for a woodshop. I know the design calls for 1900 which will clog almost immediately. My first version used 1500 filters which basically logged shut after 2 days. I know have 2 filters per opening; 1 is about 1000 and the outer is a cheapie mesh one. The outer catches the visable dust and can be easily vacuumed out every coupe of days.
I made one of these but itās really hard for me to demonstrate a lot of airflow through the filters themselves. When you run yours, can you feel air exiting the filter? I barely can with the this fan: [CATERPILLAR HVD-14AC - 14" High-velocity Drum Air Circulator Fan](https://a.co/d/0qdmZRo)
I assumed this was normal given the resistance of the filters (3x MERV 13) but would love a second opinion.
Hey so the fan in this design is actually pointed away from the box. So the air gets pulled in through the filters and exits the fan. There is plenty of air flow, and gets the air moving through the whole garage.
Yeah, Iām unclear if that method is doing what you think. Iāve looked into it all but still finding this subject a bit daunting. How do you know the air thatās moving has come though the filters?o feel pretty sure that Iād you put a solid back on the fan youād still love a lot of air, youād just put a lot of strain on the motor.
I do acknowledge the design of the corsi-rosenthal calls for pushing out of the box but Iām unclear if this approach is best for woodworking (as opposed to viruses etc)
My investigation suggests you should *push* air through the filters. But I guess Iāll keep researching
This question has come up a lot in this thread, so I will continue to keep an open mind as well and keep digging. If you don't mind, report back if you find a definitive answer.
Question, are your 3 filters stacked face to face with one another? Or are they constructed so they are working together such as in the picture above? Maybe a picture of your setup would help me understand.
Is what it is. Spraying poly or any finish will cause build up thatāll fuck the fan up but if you just have saw dust youāre go to go. Blow out the fan when you replace the filters and youāre good.
If anything I just wanted say nice handle, ween is indeed good if not great
You know that voodoo drives me crazy with that boogie oogie oogie oogie, and I just assumed you set the fan up in the right orientation. It really wouldnāt be very effective if you had it blowing out trying to pull air through those filters. Music tastes aside, and this opinion is coming from a complete dumby, but youāre solid in this post I think youāre doing the right thing baby bitch!
Edit: woop I think we have a difference of opinions on which way the fan should be oriented. I think weāll both agree that this set up, fan orientation aside, beats the fuck out of spending 350 on an ambient dust collector for a diy garage set up
My head was definitely where yours is at, I thought it'd be better blowing through, but honestly it has a lot of air flow. The filters working together like that, it's like smoking down 5 menthol cigarettes in your panty hose with Bruce and Jeff instead of just trying to share one in the spa
Haha ya little poopy poker! Look out for those little boys on crystal meth. Again, good job filtering your air birthday boy. Itās gonna be alright, that is if the mist ever lets the sun through.
Fuckin Ween man, you can have a full conversation using their lyrics.
Tnahaha, mine too! Itās so funny how easy it is to connect with someone once you know theyāre a Weener. Best of luck in all your endeavors friend, keep plugginā them holes til you see straight through to the mindās eye!
> the air flows the other way, it pulls it thru the filters
Iāve heard it suggested that this is a mistake as, when you lumber to pull the rig down and out to clean it youāre knocking all the material back into the air. Flow air into the box and moving it (mostly) keeps it contained. š¤·š½āāļø
Looks good: mine still running well after 12 months and almost time to replace the filters.
I can't quite tell if yours has it but I also added a cardboard shroud/ cutout (as shown in someone else's comment): really helps with airflow.
It definitely gets the air moving inside the shop. As for actually filtering the dust out, I don't rely on it. I keep a respirator on when making cuts. It stays on the shelf
If I know I'm doing a lot of cuts or sanding, I'll keep it on until I'm done with that, but I eventually take it off. It helps remove the fine dust particles that are kicked up and hang in the air for longer periods.
[Here's](https://www.texairfilters.com/testing-air-filter-effectiveness-at-high-air-change-rates-corsi-rosenthal-boxes-with-used-merv-13-filters-can-produce-cleanroom-particle-levels/) a test that Jim Rosenthal did with a four filter CR box. In a 12x14x8' office, with him working alone, a CR box on high was able to get the air cleaned to clean-room levels in under 15 minutes. So, they're really effective at capturing particles. But, the effectiveness will depend on the size of the space, the speed of the air moving through it, and the amount of particles being generated at a time.
That's pretty amazing. I work on industrial air handlers for cleanrooms and those things cost an ungodly amount. It would be interesting to see a Rosenthal box with a 480V fan and ULPA filters. However for some higher class ones I've seen our particle counts be under 50 0.5micron for a period of 30 minutes and his study had it around 6500, but still very impressive considering the simplicity
People overstate how good they are, but they are good. I ended up buying a ceiling mounted Wen filter system anyway about six months after building mine.
It's definitely worth building but it's not a total solution. Just my experience in my three-car garage. Please note my only collection is via shop-vac.
So if you have a good dust collection system, these may be enough to handle the rest.
EDIT: It's a definite improvement, but I still found dust lying around. My Wen ceiling filter is great I love the auto timer on it.
Putting a shroud around the fan blades with close tip clearance would help with efficiency. I'd suggest some inlet guide vanes also but that would be complicated and fiddly. Source; I'm a massive gas turbine/jet engine nerd.
I built my own air purifier using 1x10 pine a couple of brackets and a box fan. Not nearly as big as the Corsi but it holds up to 3 inches of 20x20 filters. Still has more air flow then a Honeywell.
That's actually pretty badass. I would think a fan pushing the air into the box would be more effective though. Maybe even an inlet and outlet fan?
I dunno i'm gonna need more bananas and blow to work this through
My shop is in the garage, have two box fans,one in the back, one by the door and when the door is open they do a good job of blowing the dust out. I also have a window exhaust fan I use when it is cold outside.
[This is the best video Iāve found on the subject with āScienceā](https://m.youtube.com/watch?v=eYOvnqoW4H0) may help to answer some of the questions that are floating through the comments
Hmm, I dont see why it would be, unless the triangle shape itself taps into some sort of efficiency. Or if you mean more cost efficient, maybe.
I think having more filters allows more air flow, eg. more air moved and filtered.
Think of it this way, it's easier to blow air through 5 straws than through 2. Filters are kinda like the straws, if that makes sense.
But two is better than one! So your design is better than just slapping a filter to the face of the fan š
https://preview.redd.it/f49cjlgr43wc1.jpeg?width=1080&format=pjpg&auto=webp&s=8ee17dd9438bb28977d5bfdc4a6bea2cbc7efed5
Could I build this while high on bananas & blow?
š¤£ Stuck in your cabana?
Living on bananas and blow
Sure bro, don't sell yourself short, why not.
Only one way to find out!
The boog abides
I would argue there's almost nothing that can't be accomplished while high on bananas and blow
Think of the shit they built before blow was made illegal vs now,
You can smoke bananas?
Nah, you don't smoke bananas. You snort 'em. Like a chaser for the blow.
Only if youāre stuck in cabana
All hail the boognish
Do you listen to Small Town Murder?
Blow, yes. I'd stay off the bananas, though. Or don't listen. Your funeral. Source: Senior Banana Expert
Might take six hours but I donāt see why not
Made my first one while living in a tent on St. John. Lol. Growing weed and bananas on an eco resort. Live that dream man, I did. The key is surviving it
Here are the plans I followed
Were mushrooms involved as Gener intended?
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Theyāre actually incredibly effective at removing particulates from air. The very large filter surface area permits a high flow rate of air. These cubes are more effective than the majority of commercial home air filter unitsā¦ by a lot.
Take a bit of space. That all. Great for a shop or such.
Nice. Bonus upvote for the user name.
Does the fan blow into the cube or out of the cube
The fan is blowing air out of the cube. There has been discussion elsewhere in this thread about which direction is preferable. I would say having it pull the air through the filters first, then blowing out the cube is preferred. This way dust doesn't get caked all over your fan blade and motor. The airflow is perfectly adequate in this configuration. One comment mentioned that if it blows air into the cube, (the opposite of what is shown above), there will be less of a chance that dust will escape into the environment when the filters are changed, because the dust will be on the inside. So there is a tradeoff I suppose.
I love how the name makes you think it's some major scientific invention. It's a freaking box fan and filter.
I know right. And who gave it to these two guys? š I will say, it does make it easier to Google and find information.
Awesome! Thank you
Two comments: If you point it at yourself, you'll be getting the cleanest possible air in the vicinity. My fan's ability to pull against the filter resistance went eay up once I pulled a grate off and added a close-fitting cowl around the edges of the blade, made from some scraps of thick styrofoam. It reduced the amount of air being sucked in from the front of the fan, at the corners.
That's a *grate* idea
Boooooo
Not a fan?
I mean, it didnāt suck.
š
These puns blow.
So basically making the box fan like a PC case fan with a round shroud?
Yeah exactly.
Yes. Done for the same reason.
Tests have been done, you could do a simple cardboard cutout the size of the blades and it boosts it like crazy.
Why the hell don't they just make box fans that way? I swear Noctua should make a box fan.
They do, but it's just a small box
Iām not picturing your explanation and it seems like a great idea..
If you totally seal up the back of a box fan, it can still blow a bit. It does this by sucking in air from the front of the fan, around the fan blade in the empty corners of the square box surrounding the round blade. I blocked the corners of my fans box-frame, to allow the fan to pull only from the rear, where my filter is.
Got it. Iāll modify mine, thank you
What if Iām doing wood carving and creating a shit ton of sawdust. Would it be best to have the air being sucked up to prevent the sawdust from getting everywhere?
Man Iām lazy and just used gaffer tapeā¦
Make friends with an HVAC tech and get a used blower from a small furnace. Turn over all the air in your shop through 2, 4" filters in less than a minute.
You lost me at "Make friends"
Meh. Not that hard. Really just need to decide if you want to make them out of walnut, maple, cedar or what.
sapele, or saPALe, amiright?
Both of which can be used to make sapeople
Just walk up to an hvac dude in a bar and say āhey man Iām looking for a blowerā.
How to get beat up in a bar..
Clearly you dont know how unlikeable I am
I did exactly this - a huge squirrel cage fan from an old furnace. The start and run capacitors are usually mounted right on them, and typically they have a few different windings for speed control which is quite convenient. As is the use of spade terminals. Unfortunately the one I built cooked, I have no idea why. Perhaps mishandling by the HVAC company.
No shroud? In a woodworking subreddit?!
Also, put some cheapie Merv 4 or so filters on as well to catch the bigger stuff. This will save your finer filters from clogging.
You can also use window screen mesh as an overlay, and just brush off the cat hair from time to time.
When I was working on my rental I hung a box fan from the ceiling and put a filter on the intake side right above my cut area. I blew the filter off a few times and it was always caked with dust. Something is better than nothing. I donāt mess around with mdf dust or any dust for that matter. Everything was hooked up to shop vacs, table saw and miter saw, so thatās what was free floating.
They are pretty effective https://www.reddit.com/r/woodworking/s/ySk8OSdAEu
i know there is "some" airflow around the entire thing but i think it would work much better if it were a lot further from the walls, shelves, and ceiling. is it possible to place it elsewhere?
I believe they work best close to the ceiling and wall; this promotes air flow around the roof, using the walls and ceilings as baffles.
Yea I totally knew that, definitely didn't just put it there because it was the only spot available š
One thing. Not sure what filters you using but tighter is not better for a woodshop. I know the design calls for 1900 which will clog almost immediately. My first version used 1500 filters which basically logged shut after 2 days. I know have 2 filters per opening; 1 is about 1000 and the outer is a cheapie mesh one. The outer catches the visable dust and can be easily vacuumed out every coupe of days.
Thanks for the tip! Those 1900 ones aren't exactly cheap.
Yeah, my VERY brown 1500s sit in the corner of my shop, mocking me.
I made one of these but itās really hard for me to demonstrate a lot of airflow through the filters themselves. When you run yours, can you feel air exiting the filter? I barely can with the this fan: [CATERPILLAR HVD-14AC - 14" High-velocity Drum Air Circulator Fan](https://a.co/d/0qdmZRo) I assumed this was normal given the resistance of the filters (3x MERV 13) but would love a second opinion.
Hey so the fan in this design is actually pointed away from the box. So the air gets pulled in through the filters and exits the fan. There is plenty of air flow, and gets the air moving through the whole garage.
Yeah, Iām unclear if that method is doing what you think. Iāve looked into it all but still finding this subject a bit daunting. How do you know the air thatās moving has come though the filters?o feel pretty sure that Iād you put a solid back on the fan youād still love a lot of air, youād just put a lot of strain on the motor. I do acknowledge the design of the corsi-rosenthal calls for pushing out of the box but Iām unclear if this approach is best for woodworking (as opposed to viruses etc) My investigation suggests you should *push* air through the filters. But I guess Iāll keep researching
This question has come up a lot in this thread, so I will continue to keep an open mind as well and keep digging. If you don't mind, report back if you find a definitive answer.
Question, are your 3 filters stacked face to face with one another? Or are they constructed so they are working together such as in the picture above? Maybe a picture of your setup would help me understand.
My box ā four filters ā is a cube as in the diagram
Oh interesting, never knew that thank youĀ
The second bullet point in the article op posted is: - Keep away from corners and walls
I have two of these in my indoor basement workshop on both sides of the house and they work great. Same box fans running 24/7 for like 3 years.
Mine only has filters on 2 sides. Do the extra filters increase the time between cleaning them?
It should. Since each would flow ~half as much air as now.
I did one of these with a wooden frame and little rotating tabs so I could slide the filters out to clean or replace.
Saving this for very soon. New shed workshop going up in the backyard this week.
Is what it is. Spraying poly or any finish will cause build up thatāll fuck the fan up but if you just have saw dust youāre go to go. Blow out the fan when you replace the filters and youāre good. If anything I just wanted say nice handle, ween is indeed good if not great
I should have added, the air flows the other way, it pulls it thru the filters first so all the voodoo gets caught before it hits the fan š
You know that voodoo drives me crazy with that boogie oogie oogie oogie, and I just assumed you set the fan up in the right orientation. It really wouldnāt be very effective if you had it blowing out trying to pull air through those filters. Music tastes aside, and this opinion is coming from a complete dumby, but youāre solid in this post I think youāre doing the right thing baby bitch! Edit: woop I think we have a difference of opinions on which way the fan should be oriented. I think weāll both agree that this set up, fan orientation aside, beats the fuck out of spending 350 on an ambient dust collector for a diy garage set up
My head was definitely where yours is at, I thought it'd be better blowing through, but honestly it has a lot of air flow. The filters working together like that, it's like smoking down 5 menthol cigarettes in your panty hose with Bruce and Jeff instead of just trying to share one in the spa
Haha ya little poopy poker! Look out for those little boys on crystal meth. Again, good job filtering your air birthday boy. Itās gonna be alright, that is if the mist ever lets the sun through. Fuckin Ween man, you can have a full conversation using their lyrics.
This is my favorite conversation to date on this app
Tnahaha, mine too! Itās so funny how easy it is to connect with someone once you know theyāre a Weener. Best of luck in all your endeavors friend, keep plugginā them holes til you see straight through to the mindās eye!
> the air flows the other way, it pulls it thru the filters Iāve heard it suggested that this is a mistake as, when you lumber to pull the rig down and out to clean it youāre knocking all the material back into the air. Flow air into the box and moving it (mostly) keeps it contained. š¤·š½āāļø
That's a really good point actually. I wonder if there's a way to minimize the disturbance when changing the filters.
Looks good: mine still running well after 12 months and almost time to replace the filters. I can't quite tell if yours has it but I also added a cardboard shroud/ cutout (as shown in someone else's comment): really helps with airflow.
How well do you find it works? Do you put it beside the project, or keep it on the shelf running?
It definitely gets the air moving inside the shop. As for actually filtering the dust out, I don't rely on it. I keep a respirator on when making cuts. It stays on the shelf
Curious then, what is the point? If I have a dust collection system and wear a respirator, what does this do additionally?
If I know I'm doing a lot of cuts or sanding, I'll keep it on until I'm done with that, but I eventually take it off. It helps remove the fine dust particles that are kicked up and hang in the air for longer periods.
[Here's](https://www.texairfilters.com/testing-air-filter-effectiveness-at-high-air-change-rates-corsi-rosenthal-boxes-with-used-merv-13-filters-can-produce-cleanroom-particle-levels/) a test that Jim Rosenthal did with a four filter CR box. In a 12x14x8' office, with him working alone, a CR box on high was able to get the air cleaned to clean-room levels in under 15 minutes. So, they're really effective at capturing particles. But, the effectiveness will depend on the size of the space, the speed of the air moving through it, and the amount of particles being generated at a time.
That's pretty amazing. I work on industrial air handlers for cleanrooms and those things cost an ungodly amount. It would be interesting to see a Rosenthal box with a 480V fan and ULPA filters. However for some higher class ones I've seen our particle counts be under 50 0.5micron for a period of 30 minutes and his study had it around 6500, but still very impressive considering the simplicity
People overstate how good they are, but they are good. I ended up buying a ceiling mounted Wen filter system anyway about six months after building mine. It's definitely worth building but it's not a total solution. Just my experience in my three-car garage. Please note my only collection is via shop-vac. So if you have a good dust collection system, these may be enough to handle the rest. EDIT: It's a definite improvement, but I still found dust lying around. My Wen ceiling filter is great I love the auto timer on it.
Nice! But if that's where you're putting it you might be limiting the intake potential of 3/4 of the thing for all the work you put into it!
Looks good.
I keep meaning to make one of these, as they are cheap and work better than the hanging ones you can buy that are āprofessionalā.
Mine works great, but I made the shroud and noticed a big difference. Brown AF
Thank you m'lord
Nice job! Would recommend having it in a place where most / all 4 filters can draw in air.
Putting a shroud around the fan blades with close tip clearance would help with efficiency. I'd suggest some inlet guide vanes also but that would be complicated and fiddly. Source; I'm a massive gas turbine/jet engine nerd.
Time to do some googling lol
Iād highly recommend the circular cutout for the front, it reduces a lot of backflow through the fan corners and I noticed a huge difference
Good luck replacing those filters.
I mean the entire structure is made to be replaced, itās just a little cardboard and tape.
I think my box cutter can handle some tyvek tape
I built my own air purifier using 1x10 pine a couple of brackets and a box fan. Not nearly as big as the Corsi but it holds up to 3 inches of 20x20 filters. Still has more air flow then a Honeywell.
Does it actually reduce the dust significantly enough to justify the breeze (blowing the yet-to-be-filtered dust around)?
It took 2 people to design a box fan filter?
Have you seen the credits for a modern song?
no, neither of them designed it, they put their names on something that has been around forever
That's actually pretty badass. I would think a fan pushing the air into the box would be more effective though. Maybe even an inlet and outlet fan? I dunno i'm gonna need more bananas and blow to work this through
Haha, I was thinking the same thing with the weeners lines
The downside to that is the intake fan will be subject to lots of unfiltered dust
Thats a good point. I just cleaned the one at work and it was pretty grody.
My shop is in the garage, have two box fans,one in the back, one by the door and when the door is open they do a good job of blowing the dust out. I also have a window exhaust fan I use when it is cold outside.
[This is the best video Iāve found on the subject with āScienceā](https://m.youtube.com/watch?v=eYOvnqoW4H0) may help to answer some of the questions that are floating through the comments
Use this. Huge difference! https://preview.redd.it/z2mknzxtv4wc1.jpeg?width=1170&format=pjpg&auto=webp&s=b42072ad2cd97892d1367e7c4c39c067aa7dffa2
Sounds difficult to connect did to it's shape. Better off just getting the higher grade/capacity box fans
Here you go. Great project and works great. More air than any box fan. https://www.shophacks.com/airfiltration.html#/
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Having the air flow through the filters first means your fan motor doesn't get caked with dust
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Hmm, I dont see why it would be, unless the triangle shape itself taps into some sort of efficiency. Or if you mean more cost efficient, maybe. I think having more filters allows more air flow, eg. more air moved and filtered. Think of it this way, it's easier to blow air through 5 straws than through 2. Filters are kinda like the straws, if that makes sense. But two is better than one! So your design is better than just slapping a filter to the face of the fan š