LAMINAR FLOWHOOD OVERVIEW, My DIY Centrifugal Fan Design

An overview of how I built my DIY laminar flowhood using an inline centrifugal fan. I cover all of the specs of my build and discuss tips and tricks I've learned over the years including how to tell if you're getting solid laminar flow by simply using a lighter.
Box dimensions are roughly 24" X 24" X 20". the filter is 24" X 24" and it must fit inside your box so the outside dimensions are a bit bigger.
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[@Chris-ru5hb]

Tried to replicate your success here using a centrifugal fan. Think I’ve only succeeded in creating a turbulent flow box. Lighter test bends the flame well but very jagged and uneven across the whole surface. How thick was your filter? Bought a filter labeled as laminar flow H14 but thinking it’s not thick enough to build adequate pressure to smooth out the flow.

[@RenegadeMushrooms]

You want at least a 3 inch filter, that's what mine is. You want a 99.97% or 99.99% filter like the Bonsai filters sold by "Midwest Grow Kits". Guessing that is your problem. Only other problem could be your box is not deep enough and/or your fan is blowing directly on to your filter.

[@Chris-ru5hb]

Was going to try a different fan, but it’s probably the filter thickness like you say. It was rated for 99.995 but maybe not thick enough to wash out the turbulence. That’s frustrating. It’s only 3” thick. Box depth might be too much if anything. Got it facing down like yours.

[@RenegadeMushrooms]

@@Chris-ru5hb That's interesting. My guess would be it's the filter, but not sure. There is nothing with the centrifugal fan that would cause that. I've built two hoods now with those fans and they both work great with smooth laminar flow. Also make sure you silicone between your box and filter housing so no air can escape through there.

[@RenegadeMushrooms]

@@Chris-ru5hb Actually I just checked those Bonsai filters from Midwest and they are only around 3" depth as well, but people seem to really like them. Those people there know their flowhoods really well, so you could pick their brains too. The other possibility is that the fan you have is too powerful for the static pressure of the filter. Make sure you double check those specs as well.

[@Chris-ru5hb]

I’m based in the UK, I’ll try re siliconing the joints before I take the hit on replacing the filter. Cheers for the advice I’ll keep tinkering and see what I come up with. Put some agar jars out to test it today. Pretty certain it’s too turbulent judging by your video.

[@IsomacTea]

You knoŵ what? I want to say thank you for not even a single whiff of a condescending or patronizing manner in your videos. Just joy of sharing and spreading, and treating your viewers like fellow explorers. I am older than you I believe, but when I grow up in my mushroom hobby I want to be like you 😮 Bless you and good luck in your cultivation endavours! All the best from freezing Poland!

[@RenegadeMushrooms]

That means a lot to me, thank you for watching and the nice comment 😊

[@tonystewart7624]

Thank you for sharing this tid bit brother, I appreciate it because it helped me feel a little more confident going forward to build my own. I always appreciate your videos as well, you have an easy going feel to your teaching/ sharing style. Keep up the good work 👍

[@glennplatvoet7111]

Thanks again for flow hood video ezzzie looking forward to building have a great winter keep growing 😊

[@swivels]

That's an awesome basement! Good stuff man. 💜🍄

[@jacobjamar]

The way you lay out your videos are an inspiration. I don't know if you sell or just a hobby of yours, but it's a good perspective of what to consider. I like your videos, keep it up!!

[@RenegadeMushrooms]

Mostly just a hobby, passion, obsession. Probably a blend of all three 😁. I do sell a little here and there. Thank you for the kind words and for watching.

[@JessicaSingh-bh1ni]

Thank you 🤗 for your prompt reply. I have a fan similar to yours but have not started flow hood project, still figuring out how big the box should be. Wish me luck!🤗

[@derekhinman6509]

Thanks for the update… 17 yrs…. Definitely a Rebel! 👍

[@ripptydevibes2581]

Thats awesome! We do it over the stove with great success but it is so preparing and tedious, that hood is perfect!

[@MostWantedOHA]

Good For You Mr. Renegade , i went w/ the old (new) box fan and a 2200 merv 13 filter 20 x 20 , used painters tape to attach the filter and i have a speed controller from my other round fan w/ carbon filter from my tent .works very slick . i do that too and let it run for a bit in my room before i go to work !!! id say 60$ total . sometymes i get wrapped up in making things an forget this is just a hobby not a full tyme lab. this was a couple years ago . that store still stocks those filters like 22.00$ . oh an the inline speed controller was on the amazon than can be used for many things an is simple to use if ya can plug a cord in . Thanks for you tyme and video well worth it !!!

[@cosput]

Useful tips, thanks!

[@Steveshappylittletrees]

Excellent content 🙂

[@R-Rpt]

in my own laminar flow header the fan is inside the box. I used white 1.8mm mdf and covered the countertop with glass.I made it as 30x60cm. I used an adjustable wrench to increase the fan speed as the filter efficiency drops. I prepared a 2 layer coarse filter for the coarse filter and it extended the life of the h14 filter a lot. It's very nice, thank you for your work. My biggest problem right now is preparing compost. Green mold and spider web are forming. First I boil the sawdust, bran and gypsum, after cooling I drain the water. Then I pack the 1kg compost into big freezer bags and plant the mycelium. just yesterday i lost 3 out of 6 compost from green mold and spider web, 3 of them are intact but i am half lost.

[@RenegadeMushrooms]

Sounds like you have a nice build 👍 I haven't worked with compost much, but I've heard there is an art to it. At least you have a few good bags still to work with.

[@tonystewart7624]

In my experience you have to hit the sweet spot of pasturing or you have to sterilize. But I don't use bran in my compost blend, I use straw instead and I pasteurize. My sawdust blocks I will use bran but those I always sterilize

[@paulhartzenberg9823]

Did you use the same tube type fan in your build? Do you perhaps know the model of the fan, and the specs of the filter? I'm in the process of building my own but I want to compare with someone who used a tube fan on the inside

[@R-Rpt]

@@paulhartzenberg9823 It's called the inline fan I use. You have to choose the fan values according to the filter. Use a dimmer for the fan and you can increase the fan speed as the filter gets clogged. now i have started to produce very nice shitake, lions mane and reishi. I'm thinking of building a bigger flow cabinet and expanding my business. My next goal is to produce cordyseps.

[@DangerRussDayZ6533]

perhaps try using hydrated lime to increase the PH. That will help fight Trichoderma, the most likely candidate for your green mold. I don't think it will help with the spider web mold though, not sure.

[@dirtdiggerjerry]

I use the same fan on my flow hood! Working geat

[@Tethysmeer]

I also worked two times with a sab and instantly built a little flow hood for 50$. So much comfortable to work with.

[@RenegadeMushrooms]

Agreed 100% 👊

[@jamesh3633]

Love the lure painting station 😂

[@shawnrose206]

ME TOO!!

[@bluehoney210]

Thank you so much for your thorough explanations and detailed, knowledgeable descriptions of how the flow hood functions. This helped me greatly in my build. I would love to send you a photo of the hood and video of the testing with an incense stick, but I can't put a photo or video here. Thank you again. Blessings!

[@RenegadeMushrooms]

Glad I could help, sounds like your build went really well 👍 You will find it to be a great asset for a long time in your mycoadventures.

[@mwkennedy80]

Thank you again for your videos, I created a still air room, contamination hasn't been an issue yet. Was trying to figure what size flow I would like, 2x2 looks about right

[@RenegadeMushrooms]

I like the 2' x 2', but 18"x24" is nice too if you find a good price on a filter that size.

[@rickm1041]

All your videos are great man really appreciate it. Could you tell me how you mounted your centrifugal fan I'm building a 24x24 myself

[@RenegadeMushrooms]

Thanks, I just cut a hole in the top of the plywood box with a jigsaw and siliconed it in place.

[@RoyWanfried]

I also built my second one.

[@goombaspore7386]

I’ve been curious about this kind of setup.

[@RenegadeMushrooms]

Centrifugal fan works well 👍

[@Pjbanana29lol]

Hi thanks for the video! Just wondered how you got the fan to fit so it's air tight? I know the squirrel box can be screwed into the wood but am looking at this type you went for as my preferred option. Many thanks

[@RenegadeMushrooms]

I just cut the hole so it would be a nice snug fit and sealed it in there with silicone.

[@natek.2051]

Love the channel man. I also make wine and fish. Do you have any videos of your other hobbies?

[@RenegadeMushrooms]

Glad you found the channel and thanks. I do have a fishing channel as well. I mostly fish Lake Ontario and tributaries, but I also do some east coast saltwater stuff. Here's a link to the other channel: kzbin.info

[@CamxCam.]

Thank you for this. I saw one with a dark stain & a nice decorative wood trim that made the filter look like it was in a fancy frame. I'm itching so hard to start this project. I'm tired of being confined to a SAB. Just wanna ask... is this filter 6 or 11.5" deep?

[@RenegadeMushrooms]

6", also 99.99% or 99.97% both work fine.

[@SporeWhore661]

I ordered the nomad lyte from lab rats flow hoods, can't wait to get it. Hopefully I can upgrade pretty quick to a 24 × 48 hepa laminar flow hood. Wanting to get a small gourmet medicinal mushroom farm so make some money out of the hobby I love ❤

[@RenegadeMushrooms]

Awesome, let me know how it works for you.

[@justinvassar3984]

Thank you for sharing. Ultimately are you glad you used a centrifugal fan? After reading up so much on fan curves I don't understand how a 460 cfm fan is sufficient to create laminar flow over 4sq ft, but 17 years of use doesn't lie.

[@RenegadeMushrooms]

Well, to be honest, math has never been my strong suit 😁 But, when I built this thing once upon a time, I spent a lot of time figuring out the cfm's, and I thought I nailed it. Testing it with the old school lighter flame trick tells me it's good flow, but that's as fancy as I get. Yes, I am happy that I went with the centrifugal fan. They are widely available in a range of powers, and many can be throttled up or down by purchasing a rheostat. They are less expensive than the squirrel cage style as well.

[@michalparchimowicz]

That is real gold contetnt :). Just if You can put some links to filters because im not sure who to trust :). All the best man!

[@RenegadeMushrooms]

The place I bought mine is out of business I think. These guys have nice filters: www.midwestgrowkits.com/bonsai-flow-hood-99-99-hepa-replacement-filters-regular-xl-or-commercial.aspx?feed=Froogle&gclid=Cj0KCQiAw8OeBhCeARIsAGxWtUyUeAZaeQo2PM_Akainlaq5sU6BJkCpa3ymUvM586sfPytpiJgqyGEaAqfLEALw_wcB

[@michalparchimowicz]

@@RenegadeMushrooms Thank You very much.

[@JDvb23]

GrodoTEK made a smaller one with a 66qt sterilite and a variable speed fan, wondering if someone would be able to recreate a similar design but with a bigger filter. I’d love to have a 2ft one like this but I don’t know the logistics and money is not a resource I have to experiment with lol, hopefully someone makes one of these with a updated design

[@RenegadeMushrooms]

This site us a great instructional source in case you decide to build one: www.fungifun.org/English/Flowhood

[@unreality4337]

So is there also a fan onn the inside against the back wall pointing towards the hepa filter?. It must be large enough to cover hepa?

[@RenegadeMushrooms]

No, just the fan on top. The role of the fan is not to blow through the hepa, it is to pressurize the box, forcing a smooth flow of clean air out through the hepa.

[@mycologycorner]

Love it. I just built my 7th hood. My ex business partner stole my last one smh and rest of my equipment.

[@RenegadeMushrooms]

Damn that's cold. Well, plus side is, you're a pro flowhood builder at this point.

[@mycologycorner]

Lol good point I had to make my KZbin channel private so this jerk can’t train off my videos. You have a Instagram? I have lots of pics of my last farm on my ig. It was so sweet. I’ll have everything back by January can’t keep a good farmer down.

[@RenegadeMushrooms]

@@mycologycorner No Instagram for me, I can barely keep up with YT and FB.

[@concernedcitizen8419]

Use shopvac filter at your intake for pre filter

[@RenegadeMushrooms]

Cool idea 👊

[@d4vidneo524]

Hello how are you, impeccable video, I'm going to imitate the same, phenomenal, I'm investing money in this beautiful jovit of mycology, excuse my English, it's translated, I'm actually Latino, that box is beautiful, I also want to work with more space and comfort, it is always good to work in a sterile environment, I suggest you install a uv-c light in the basement since there are many particles in suspension with mites above all, the uv-c light eliminates them all. I was impressed when you mentioned that you have been using this filter for 17 years, impressive, that detail of covering the filter with luxury magnets, my friend.

[@RenegadeMushrooms]

Thank you. You will love having a flowhood. It opens a new world of possibilities for mycology. I would be lost without it in my dusty old basement 😁 Good luck and let me know how it works for you. The translation was excellent by the way, mushlove 👍

[@d4vidneo524]

@@RenegadeMushrooms thank you friend and excuse my previous comment about the pre-filter, if it continues to last you for more than 17 years it is because this pre-filter is very good, grateful to you who contribute to this great world, it is 600 USD that I am going to invest, I already ordered the fan is 522 CFM, I would only need the 24x24`` filter

[@RenegadeMushrooms]

@@d4vidneo524 Cool, and thank you for the kind words. My filter has lasted a long time, but I plan to replace it soon. I recently purchased a new one to eventually replace it. Here is a link to the one I bought, just for reference: www.steam-brite.com/clean-storm-hepa-filter-24in-24in-9997-particle-board-242406h910-h24240699-h24240699-p-89060.html?gclid=Cj0KCQjwg8n5BRCdARIsALxKb94Fj9OQgXBuZ4s8UoIedJ6fFgEqdIQMXI6dfEmbBgQoHWgCMCD6dG8aAnYdEALw_wcB

[@nicolebarton6158]

I love it, kinda like my “dungeon”. Got my tent, poor man flow hood, table with watercolor paintings, next table with my drones, lock picking sets, soldering station, felt nitting. I am a girl. And that’s just one office/ living room. What would we types be called, professional hobbyists? But mycology is quickly ramping up to #1. I want to fruit the world, using birds to spread mycelium, in the bird seed. Make it a protected thing , mushrooms could save this world! I honestly believe it, from the spiritual with magic mush, polypores and bears and honey bees and turkey tail and cancer, lions mane and brain cells, black oysters and run off! I mean why the hell is this not a bigger deal? Thanks for the rant,,you got a nice voice. I am such a damn girl

[@RenegadeMushrooms]

Thank you and yeah I love my dungeon too, organized chaos but functional. I have a few other hobbies, but mycology took me over when I first got into it. I've always spent most of my time outside and been fascinated by the natural world and mushrooms are all of that and then some. I love watching them grow, how every strain and species has their own subtle tendencies and personality. Hunting the woods for them is like a treasure hunt. Glad you liked the video, thank you for watching.

[@Buddha_Approved]

So if i am filling a 10 x 15 area (10 x 10 for bags and 5 x 5 clean room) will a 2' x 2' flow hood do trick or do i need to go bigger like 2' x 4' (which would be 2 (2 x 2 hepa/flowhoods stacked)

[@RenegadeMushrooms]

2' x 2' would be fine.

[@NOT0RI0US]

Hermano yo soñaría con un sótano así para trabajar. Yo hago mis transferencias sentado en mi cama sin flujo laminar, con un mechero de alcohol. Hasta me toco hacer mi propio agitador magnético 😅 Buén dato el del motor. Gracias x el video

[@RenegadeMushrooms]

I started out growing in a little one bedroom apartment myself. Maybe some day you will have more space. The cool thing about growing mushrooms is you can have fun and success with it just about anywhere.

[@NOT0RI0US]

@@RenegadeMushrooms Si tienes razón. Incluso gaste los ahorros para mi computador en elementos de micología, le estoy metiendo el hombro al tema 😍 Lo gratificante es que estamos cultivando vida, eso es lo que me atrapa del tema. Hacemos lo que sea para que ellos puedan crecer felices. Saludos de Colombia 👊🏾

[@michalparchimowicz]

Hi Renegate. I'm about to buy (at last) H14 filter 61x61x29(thiknes) cm with aluminium separation. I want to recreate your construction like in this video. Can you help me how to calculate air space in the box i need? And am I right about all this idea? Will the blower will be enough withis kind of thiknes? Im from eastern europe and here is huge problem with filters. Manufacturers here don't have graphs of efficiency of air flow. I hope i didn't complicate to much this post ;))). Have a great day!

[@RenegadeMushrooms]

Because of the thickness of your filter, you will need a more powerful fan than what I have. Your filter will have a higher resistance than mine. Here is a link to help you out: www.fungifun.org/English/Flowhood Also you can ask on the "Mushroom Growing for Beginners and Experts" Facebook group. Someone there may have the same filter as you.

[@dylski4294]

Is the metal trim holding and securing your HEPA filter in place? I know your filter is 24x24. What is the length/dimensions of your plywood around the filter? Is it also 24 x24?

[@RenegadeMushrooms]

Actually the filter fits pretty tightly inside the box, and I ran silicone around where the filter and box meet to seal it. The metal trim in really just decorative. I built the box to fit tightly around the filter, so the opening is roughly 24" X 24". Don't build the box though until you have the filter because the dimensions can vary a little.

[@dylski4294]

@@RenegadeMushrooms Thanks. What is the depth of your box?

[@RenegadeMushrooms]

@@dylski4294 20 inches

[@dylski4294]

@@RenegadeMushrooms Okay thanks so much Broseidon 🔱

[@denisemcdonald4691]

How do you clean it between uses? All the dust and stuff settles on so when you turn it on aren’t you just blowing that dust and stuff on whatever you’re working on?

[@RenegadeMushrooms]

I always start it up a half hour or so ahead of time to clean the air in the area. Then I wipe down the work area with isopropyl right before I start working. The only thing I ever actually wash is the pre-filter. It's made of a synthetic mesh material so I just wash it with warm soapy water, let it dry, then re-install. Eventually your main HEPA filter will become clogged and your airflow will drop way off. At that point you need to replace the main filter. A good washable pre-filter will greatly extend the life of your main filter.

[@brucetheshroom9973]

How are you securely mounting the fan unit to the top? Is it just sitting on top or is there a rubber gasket on the hole? Did you use any screws too secure? Thanks very much!!!

[@RenegadeMushrooms]

No screws, just a bead of clear silicone to seal it in place.

[@brucetheshroom9973]

@@RenegadeMushrooms Easy peasy! Thx!

[@LESSISMOREMOREORLESS]

I just remembered I have a 190 CFM centrifugal fan. Will that be enough to pressurize a 18x24? Or more likely a 12x12?

[@RenegadeMushrooms]

Probably more like 12 x 12. Hit up midwestgrowkits.com and see what there Bonsai 12 x 12 filter requires.

[@LESSISMOREMOREORLESS]

@@RenegadeMushrooms good tip. theirs is 200 CFM but that's pretty close and $93 for a filter aint bad. cheers man!

[@SporeWhore661]

Should use a induction fan, quiter and has 3 speed control.

[@RenegadeMushrooms]

Actually you can get these inline exhaust fans that can be controlled by a rheostat making them infinitely adjustable. The second hood I built uses one and it works great.

[@user-qt6wv9se8g]

Hi there! Could you say how thick is your pre-filter material ?

[@RenegadeMushrooms]

It's about .5" thick I would say. It's the pressed polyfil type fabric that is often used as packaging material. It's also used in inexpensive furnace filters.

[@JessicaSingh-bh1ni]

Hello Did you install a fan controller switch? Cool flow hood

[@RenegadeMushrooms]

Not on this one, but I did on the second hood I built for a friend. This was my original and this fan isn't compatible with a rheostat. I definitely recommend purchasing a fan that can be adjusted if you can find one.

[@tonywebster8884]

Where is the best place to purchase the 2' × 2' final stage hepa filter?

[@RenegadeMushrooms]

This is one source I've purchased from: www.steam-brite.com/clean-storm-hepa-filter-24in-24in-9997-particle-board-242406h910-h24240699-h24240699-p-89060.html?gclid=Cj0KCQjwg8n5BRCdARIsALxKb94Fj9OQgXBuZ4s8UoIedJ6fFgEqdIQMXI6dfEmbBgQoHWgCMCD6dG8aAnYdEALw_wcB

[@holdisgold6157]

Hey man, what is the depth of your filter for this set up please

[@RenegadeMushrooms]

6"

[@dandelionboy7820]

Is this a 5 7/8" deep filter? How long did this filter last? I'm trying to build one, but I don't want to use the 11.5" deep model. Does the depth really affect the life of the filter that much?

[@RenegadeMushrooms]

I can't remember for sure, but it was either 4" or 5 7/8", definitely not 11.5" Don't judge me, but mine is 17 years old. I've never changed it because it still works great.

[@dandelionboy7820]

I wouldnt judge. The life expectancy on a hepa filter is very convoluted I've been finding out. They say that the thinner thinner ones don't last as long as the ones a foot thick bc the thicker ones have more media and can hold more particulate. However, I actually was reading a case study done to determine the exact life expectancy of a hepa filter to expect. I don't think the filters in the study were being used in this scenario or in a mycological framework at all but from what I read hepa filters can last more than 20 years without a significant pressure drop (some filters lasted up to 50) IF a pre-filter is used and other environmental conditions are met. Like I don't think filters like outside air much. But the study didn't specify the thickness of the filters used throughout the test. They averaged the performance and life expectancy of over 16,000 different hepa filters with varying ages. So I was trying to hear the thoughts of ppl that have been using 5⅞" filters in this configuration for years. I really don't want to build a box around a filter a foot deep if I don't have to especially if the other ppl are have success innoculating agar, spawn, and production blocks free from contamination using a thinner filter. Using a thicker filter will take up alot of room.

[@RenegadeMushrooms]

@@dandelionboy7820 I agree that I think the pre-filter is key. I've never run mine without it, and I clean it periodically. Other people I've talked to have said the same.

[@user-yq8he1hu6m]

Hello, you write in the comments that the second hood is with speed control...please give me a link to a fan with speed control.The video is great!!!

[@RenegadeMushrooms]

They're lots of them out there, just search Amazon for "inline duct fan rheostat control"

[@J155P]

I believe the white side of your pre filter should be facing out. I could be wrong, but thats what I was always taught.

[@RenegadeMushrooms]

I guess that would make it easier to see if it was dirty, but other than that I can't see why that would matter. It's just compressed poly and I've been running it that way for 18 years or so and it still works mint.

[@J155P]

@@RenegadeMushrooms Right...and with the success you've had with your HEPA filter, I'm sure it doesn't matter that much at all. Really enjoy your channel.

[@RenegadeMushrooms]

@@J155P Thanks man, and thanks for watching 👊

[@DrGaryGreen]

I'm trying to find a filter, what one do you use and where do you buy it? Thank you.

[@RenegadeMushrooms]

They're tough to find. I bought this one not long ago as an eventual replacement for my old one: www.steam-brite.com/clean-storm-hepa-filter-24in-24in-9997-particle-board-242406h910-h24240699-h24240699-p-89060.html?gclid=Cj0KCQjwg8n5BRCdARIsALxKb94Fj9OQgXBuZ4s8UoIedJ6fFgEqdIQMXI6dfEmbBgQoHWgCMCD6dG8aAnYdEALw_wcB

[@DrGaryGreen]

Only 6" thick. Thick enough?

[@thatgirl9938]

Question why do you need the box would it not work with just a fan behind it?

[@RenegadeMushrooms]

No, you definitely need the box. The fan is not so much blowing air through the filter as it is building pressure in the box behind the filter. It's this pressure build-up that leads to smooth laminar flow through your filter with little to no turbulence. Turbulence causes swirling flow that can bring in contams to your work space. Hope that makes sense.

[@blschneider]

How did you mount the fan onto the box?

[@RenegadeMushrooms]

Cut the hole with a jig saw, sat it in there, and siliconed it in place. That's it 👍

[@billlumberg5746]

Where could we get a reasonably priced hepa filter?

[@RenegadeMushrooms]

Midwest Growkits has Bonsai hepa filters. People seem to like them.

[@user-yq8he1hu6m]

Sorry for my English, I'm writing with the help of a translator. I can't find your engine anywhere in Google (by the inscription on it) Please share the link. What do you think, if the engine is more powerful, but it will have a speed controller. Will it be possible to adjust it to laminar flow in your box?

[@RenegadeMushrooms]

This is the one I used in the video, but it can't be adjusted. www.aero-flo.com/centrifugalfans/ Model CF150 If I were you I would buy a more powerful one that can be adjusted down using a rheostat.

[@user-yq8he1hu6m]

@@RenegadeMushrooms Thank you very much !!!

[@mikemyers791]

Where did you get your handles at

[@RenegadeMushrooms]

It was a long time ago, can't remember. These look similar though: SAIYEN Stainless Steel Ring Handle Folding Pull Handle Heavy ... g.co/kgs/bj1i4D

[@mikemyers791]

What are your box dimensions, would like to know.

[@RenegadeMushrooms]

Roughly 24" X 24" X 20" deep. The filter is 24" X 24" and it has to fit inside your box so your outside dimensions will be a bit bigger than that.

[@techendeavor7827]

Where’d you get the filter at ?

[@RenegadeMushrooms]

www.steam-brite.com/clean-storm-hepa-filter-24in-24in-9997-particle-board-242406h910-h24240699-h24240699-p-89060.html?gclid=Cj0KCQjwg8n5BRCdARIsALxKb94Fj9OQgXBuZ4s8UoIedJ6fFgEqdIQMXI6dfEmbBgQoHWgCMCD6dG8aAnYdEALw_wcB

[@user255]

Most HEPA filters are also washable.

[@RenegadeMushrooms]

Never heard of that, but I'm guessing it's pretty involved. Mine has a particle board frame, so that might not work??? My old girl is pretty beat up anyway. I'll probably try to get my new one in this winter at some point.

[@user255]

@@RenegadeMushrooms HEPA filters certainly doesn't look like washable (the material looks like paper/cardboard), but they usually are. You just have to be careful, because they become heavy and bit more fragile when wet. They should be dried flat on wire grid or similar. Usually manufacturers put some small marking on the filter whether it can be washed and if so, how many times. I always wash them, because damn they are expensive. Btw. I prefer some walls and roof around the working area to direct the flow into my direction. And also to prevent turbulence mixing dust into the flow. Have you had any contamination issues? However, that necessarily creates some restrictions to the working area.

[@RenegadeMushrooms]

@@user255 I don't have much of an issue with contamination, but most of the techniques I used are geared towards minimizing contams anyway. I have been doing a bit of agar cloning this year though with minimal contams so I seem to be setup ok.

How to buy fillter 24’ x 24’ ?

[@RenegadeMushrooms]

www.midwestgrowkits.com/bonsai-flow-hood-99-99-hepa-replacement-filters-regular-xl-or-commercial.aspx

[@bmartin2304]

Cool build. One small suggestion for your intake filter. get an increaser cone from 6 to like 10 inch, then put the filter on the larger pipe diameter. need to upsize to overcome filter restriction, will be easier on the fan too. Obviously its working fine but just my thoughts. You could also do like a 6 inch tall plenum box that sits on top with a larger filter intake, it would look way cleaner like this, no cone sticking out the top. or better yet, just put an open topped box on top that hides the fan and sticks up about 4 inches above it, then get 24x24 or 24x whatever filters that just sit on top.

[@RenegadeMushrooms]

I like the increaser cone idea 👍 I actually factored in the reduction in cfms from the pre-filter into my hepa filter resistance calculations though. I've been rocking the same fan and filter for 18 years, only occasionally washing the pre-filter. Can't believe it's still working with no contams.

[@bmartin2304]

@RenegadeMushrooms thats awesome man, 18 years, geez.

[@DavidGarcia-pe2bq]

How big is your hepa filter

[@RenegadeMushrooms]

24" x 24"

[@shaunm1983]

I use cheese cloth as a pre filter 😅

[@RenegadeMushrooms]

That's a cool idea, I really like this synthetic pressed poly stuff though if you can find it because it washes and dries easily. It's like the stuff they make the cheap furnace filters out of.

[@shaunm1983]

@@RenegadeMushrooms Yer that stuff sounds ideal

[@bronsontate3192]

What size is the fan..

[@RenegadeMushrooms]

6", 460 cfm

[@Bearsfan131]

@@RenegadeMushrooms where did you get the one you put a speed controller at?

[@RenegadeMushrooms]

@@Bearsfan131 amazon

[@RenegadeMushrooms]

@@Bearsfan131 JOD Router Fan Variable Speed Controller Control for Electric Motor Rheostat AC 120 Power from 500w to 1800w Adjuster a.co/d/2CVX6oo Similar to this 👆 Just make sure it will work with your fan.

[@Bearsfan131]

@@RenegadeMushrooms awesome thanks. Where'd you get that fan?

[@95manneya]

Does anyone know where to get a filter like this under $200? On Amazon they are outrageously overpriced in my opinion

[@RenegadeMushrooms]

www.midwestgrowkits.com/bonsai-flow-hood-99-99-hepa-replacement-filters-regular-or-xl.aspx?feed=Froogle&gclid=Cj0KCQjwyOuYBhCGARIsAIdGQROPuxBzf975NG1yooh4EZr8std95P45da9Z3Wm8q7eCw9-sdVM7FisaAhecEALw_wcB 24"x18" is $259.99

[@justinw.7045]

0:55 If you can dodge a wrench....

[@myco-syco]

Any recommendations to a 24x24 filter? Only ones I can find are like 11.5 inches deep 😂...although good pricing it's just going to be WAYYY too big of a box for me with that depth

[@myco-syco]

I can resort to the 24x18 bonsai but l need something a little taller for bags

[@myco-syco]

Nevermind! Found 1 that's 24x24x5 7/8 could u link me to your fan?

[@RenegadeMushrooms]

@@myco-syco 460 cfm www.aero-flo.com/centrifugalfans/

[@SwiggitySwagDopeInTheBag]

this is not a hood, a hood is called a hood because it has an actual hood. This aint it chief

[@RenegadeMushrooms]

This design is commonly called a "Flowhood" in amateur mycology circles, so that's what I go with. Probably because it's shorter than "Table-Top Hepa Clean Airflow Device". That just doesn't roll off the tongue.