Doin' my crappy little crafts to survive the crappy little smokepocalypse...

Jul 17, 2026 6:19 PM

MrStealYourGiF

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250

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I was thinking about doing this Weds, but forecast said smoke was clearing out overnight, then Thurs, ditto.... so now expecting we could have a week of it, I thought I better move my ass.

This is a not very ideal implementation, ancient fan on it's 3rd life, got it greased up and running good though, and some surplus 4 pack of 12" filters I got some time back for $5, so I've probably got $7 in the whole thing. The 12" fan was only somewhere in the range of approximately the idea of 12 inches so it's an OCD nightmare with it not quite squarely on the box and needing patch pieces etc. Also IDK if it's picked up, the 2nd roll of duct tape was half a tone different color white than the first, quelle horreure.

Anyway, here's the more extra properer way of doing it, don't replicate my mess..
https://cleanaircrew.org/box-fan-filters/
https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box

I guesstimate mine is probably only good for about 50% reduction and 5-10 cubic meters a minute.. be alright with recirculation in a small room though, knock it down a bit. Also got some activated charcoal on my filters so might do something for VOCs.

Well done.

1 week ago | Likes 2 Dislikes 0

there's a yt video of a guy testing filters and he did the same. YT/@The3DHandyman

1 week ago | Likes 1 Dislikes 0

Don't forget the circular shroud on the front to prevent non filtered air from getting pulled in outside the radius of the fans. A tissue paper will show you where it's getting sucked in vs blowing out on the face of the box fan.

1 week ago | Likes 5 Dislikes 0

Good point, mine doesn't show from that angle due to depth of slats, I have one mounted inside the fan.

1 week ago | Likes 3 Dislikes 0

Make sure you're using a high enough merv rating. Anything under 9 is pretty useless for smoke (Still captures but at a very low rate). Anything over 13 is overkill (only if you want ultra clean air). Higher the merv rating the lower the airflow too. Additional fans for circulation can help move the air around more so it works towards the filter faster to be captured. As overall air circulation affects how quickly it cleans the air more than how much air is pulled through the filters.

1 week ago | Likes 3 Dislikes 0

Umbrella cover from the sun.

1 week ago | Likes 1 Dislikes 0

I'm actually getting good objective data here from Home Assistant: Our Pm2.5 outside was 180+ this morning, in my room (no filters) it was 120, in my living room (normal sized air filter) it was around 40, and in my wife's room (with the Honeywell HEPA round thing) it was 18.

Obviously it's Honeywell round thing for the win, but even the normal filter made a difference.

1 week ago | Likes 21 Dislikes 0

What do you use to measure the pm?

1 week ago | Likes 1 Dislikes 0

Spray the filter with a little bit of light oil, such as baby oil, and it will improve significantly.

1 week ago | Likes 5 Dislikes 0

The one in my kitchen has been misted with years of oil, no worries

1 week ago | Likes 5 Dislikes 0

Not onlyfans (also filters)

1 week ago | Likes 14 Dislikes 0

that air conditioner looks like it’s wearing a lopsided hat

1 week ago | Likes 3 Dislikes 1

‘You sir, are a steely-eyed missle man!’ - Apollo 13

1 week ago | Likes 3 Dislikes 0

Well. If it worked for Apollo 13, it should work for you

1 week ago | Likes 1 Dislikes 0

Get a 20x20 box fan and same sized filter for the back side

1 week ago | Likes 2 Dislikes 0

How to destroy a fan in 2 easy steps:

1 week ago | Likes 1 Dislikes 0

How?

1 week ago | Likes 1 Dislikes 0

Good job! Any improvement is improvement.

You can actually get this kind of filter working better by buying some of the more expensive furnace filters in the same size, ones rated for lower micron particles, like HEPA filters and such. The way to make that work without spending quite as much money replacing the expensive ones, is to tape them to the cheap filters, with the cheap filters on the outside and the expensive ones on the inside. The expensive ones last longer that way.

1 week ago | Likes 5 Dislikes 0

what do you mean crappy. that setup is the best air purifier you can "have" for almost no money, according to rtings - https://www.rtings.com/air-purifier/reviews/best/air-purifiers

1 week ago | Likes 1 Dislikes 0

Box fans are surprisingly extremely loud. You think you can get used to the noise, but you won't. It is just so very loud.

1 week ago | Likes 1 Dislikes 0

got to be careful with something like this though. that fan is *not* designed to endure strain when pulling air through and can easily overheat from the resistance from those filters. with the paper filters underneath and running it for a long time you're setting yourself up for a potentially dangerous situation. at the very least, make sure you don't leave this running unattended eg while sleeping

1 week ago | Likes 1 Dislikes 0

To be fair to sauron35, the data on fan safe was a bit buried. To be fair to MrStealYourGIF, Underwriter Laboratories (UL) did test the fans with complete obstruction. UL datasheet I dug around and found: https://chemicalinsights.ul.org/wp-content/uploads/2021/07/DIY-Box-Fan-Report-2021.pdf

Buried three links deep in the articles posted is the promised safety info: (two twitter/x posts showing a different config (1 small filter) and a dead UL link).

1 week ago | Likes 1 Dislikes 0

To save anyone needing to click and interpret the data, the temperatures on the obstructed fans reached their hottest point about 30-60 minutes in and remained pretty consistent. 5 fans were tested and none broke 80c. The non-obstructed fans were closer 20-40c range.

1 week ago | Likes 1 Dislikes 0

ah, a "Tell me you didn't read the links without telling me you didn't read the links."

1 week ago | Likes 2 Dislikes 1

12" ≈ 30.5 centimetres

1 week ago | Likes 1 Dislikes 0

or 2 bananas

1 week ago | Likes 1 Dislikes 0

Does it suck air from the room and then blow it down thru the filters? or does it suck from the filters and blows up into the room?

1 week ago | Likes 2 Dislikes 0

pulls in through the filter and out through the top. Make sure filter flow arrows point inward if doing it that way.

1 week ago | Likes 2 Dislikes 0

Thanks! do you think it matters if it pushes air or pulls air?

1 week ago | Likes 1 Dislikes 0

This way round seems to be recommended, see links above. Not sure of filtration difference, but common sense wise, it seems it may peel itself apart blowing inward.

1 week ago | Likes 2 Dislikes 0

The static pressure from most fans is better when sucking over blowing.

1 week ago | Likes 3 Dislikes 0

Static pressure was my biggest worry on the older fan, just because it spins freely and can move some air doesn't mean it can pull much through, but anything helps.

1 week ago | Likes 1 Dislikes 0

I just taped one to the back of the fan

1 week ago | Likes 8 Dislikes 0

I was just looking at pressure drops of various types and it seems like a 4" or 5" deep square filter taped on back of fan might do well.

1 week ago | Likes 3 Dislikes 0

tried that once when i was about 12. i guess the constant restriction with the fan running over night made the motor start to smoke.

1 week ago | Likes 3 Dislikes 0

Yep, it'll do that.

1 week ago | Likes 1 Dislikes 0

I see an anxious person doing something, anything, to feel less powerless.

1 week ago | Likes 3 Dislikes 23

You have some weird idea of why people do this and your notion in the other comment that people don't die from it is also weird. Maybe you should chew some asbestos. It won't kill you anytime soon either

1 week ago | Likes 18 Dislikes 0

That's right, I'm weird because I analyze emotional motivations for behavior. I'm sorry you weren't able to understand.

1 week ago | Likes 1 Dislikes 20

You're not weird, you're sad. I pity you. I wonder what has happened in your life that has led you to belittling others over your own misunderstandings. Your musings of "having a higher understanding" that are indeed quite backwards, ironically. You don't seem to understand much of anything. Smoke inhalation is bad. This helps reduce smoke inhalation. That's it, that's all that's going on here. You seem to think it's some sort of firefighting device, which is quite absurd. Please get therapy.

1 week ago | Likes 2 Dislikes 0

I'm able to understand you're an idiot that think smoke is npnp and people doing things that works against it inside only is because they do it to feel less powerless

1 week ago | Likes 15 Dislikes 0

He's just an insecure, weak little man that makes himself feel better about his shitty life by insulting and/or attacking others. Your best bet is to block and move on.

1 week ago | Likes 8 Dislikes 0

1 week ago | Likes 5 Dislikes 0

I'm sure this is not new information to them lol

1 week ago | Likes 4 Dislikes 0

This is exactly what my friend did to survive CA wildfires in the past. He has since purchased a couple of air-purifiers, but this works!

1 week ago | Likes 58 Dislikes 0

A decent filter and fan will help out. Cheap and effective, perhaps not the best but I bet all the air filters systems are sold out at hardware stores.

1 week ago | Likes 5 Dislikes 0

It's called a Rosenthal Box, in case people are wondering. 20 inch box fan, and four 20 inch filters, plus masking tape.

1 week ago | Likes 3 Dislikes 0

Unless your friend was in direct peril from being burnt to a crisp, your friend was never in danger of not surviving. putting up an air filter was a coping mechanism to a situation that made them feel powerless. Evidence: all the ppl that didn't do that and survived just fine.

1 week ago | Likes 3 Dislikes 69

Heh it’s Elon with all his gay mars posts! Come look!

1 week ago | Likes 4 Dislikes 0

Annnnd another stupid fuck blocked.

1 week ago | Likes 37 Dislikes 0

tell that to my pet that died during those fires due to smoke inhalation. you don't know shit and clearly just want to shit on parades. troll somewhere else

1 week ago | Likes 15 Dislikes 0

They clearly didn’t have advanced human lungs /s
But I am terribly sorry for your loss :( what was their name and what pet were they?

1 week ago | Likes 3 Dislikes 0

So unless something actually kills you it’s totally fine and you’re a sissy for worrying about it. Got it.

1 week ago | Likes 7 Dislikes 0

You do realize that smoke inhalation is cancer causing right? Not to mention it'll fuck up your lungs

1 week ago | Likes 4 Dislikes 0

Are you a retired cigarette industry lobbyist by any chance?

1 week ago | Likes 28 Dislikes 0

1 week ago | Likes 4 Dislikes 0

Hahaha!

1 week ago | Likes 4 Dislikes 0

Wow, you're stupid. #Dumbass

1 week ago | Likes 18 Dislikes 0

1 week ago | Likes 4 Dislikes 0

1 week ago | Likes 3 Dislikes 0

psh, those people just didnt find the right coping mechanisms (/s)

1 week ago | Likes 9 Dislikes 0

1 week ago | Likes 2 Dislikes 0