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Stipe-n Cap


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So you're building a flowhood....easy flowhood math template. 14
#26679345 - 05/18/20 05:04 PM (3 years, 8 months ago) |
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There seems to be a lot of confusion when it comes to selecting a filter, then matching it to a blower. In this post I'll attempt to make a no-brainer, fill in the blanks Aide-mémoire for people struggling with the math. Each line in this template will inform the next, this is why you need to solve the filter issue before tackling the blower. Choose the filter first, then match the blower.
Not all High Efficiency Particulate Air filters are appropriate for laminar flow applications. HEPAs have a wide range of applications from furnace air filtration to Hospital and laboratory applications.
HEPA filters remove particulate such as micro-organisms, pollen, and mold spores from the air. HEPA filters used in clean benches should have a minimum filtration efficiency of 99.99% against airborne particles 0.3 microns in size. Filtration efficiency will be greater than 99.99% on particles that are larger than 0.3 microns.
My current filter is 99.999% down to .1 micron.

Not all flow regimes are appropriate for laminar flow, laminar flow is not just any ol breeze coming out of any ol filter, as mentioned above. Laminar flow is orderly and parallel, turbulent flow however is chaotic and non linear.
Laminar flow occurs when a fluid (like air, air behaves the same as a fluid) flows in parallel layers, with no disruption between the layers. ... Turbulent flow is a flow regime characterized by chaotic property changes. This includes rapid variation of pressure and flow velocity in space and time.
Don't expect laminar flow just because your fan has a HEPA filter on it, if you don't follow this template you can be assured that you will have turbulent flow.
Turbulence = contamination
 
This is a great example of what not to do:
The TemplateStep 1: The filterAfter you've decided which HEPA filter you want you'll need to download the .pdf file for that filter or ask the retailer/manufacturer to supply the spec sheet which will have the velocity/resistance chart:  Here is a sample chart for a 2ft by 4ft HEPA which shows three different filters by thickness represented by the three different coloured lines. On the left you will notice that it's labelled "Resistance [W.g]" W.g stands for Water gauge and it's the unit of measure used to measure your static pressure (SP). Before you can match any blower to your filter you need to find out how much resistance (Static pressure) your HEPA has at a velocity of 100 feet/min +/- 10 FPM. 100ft/min is the minimum velocity necessary to achieve laminar flow across the surface of your filter. FPM refers to the "air speed" produced by the filter(at a specific static pressure), as measured in Feet Per Minute. CFM is a measure of the "air flow," stated in Cubic Feet per Minute. In other words, FPM is a measurement of how fast (velocity) the air moves and CFM measures how much air is moved (volume).  The red line show's exactly where the filter (green line) intersects with the W.g on the left and 100 feet/min on the bottom, it's now clear that this filter produces .5 inWG of static pressure at 100 feet per minute. Now it's time to figure out the volume of air we need to move to achieve a velocity of 100ft/min across the surface of the filter. 1. HEPA measurements:Length___ft x width___ft = ___ft² 2. Flow rate:100ft/minute x ____ft² =____ft³(CFM) Maximum CFM for the filter is +20% of minimum CFM. So let's use this template with the filter represented by that chart above. 1. HEPA measurements:L_4_ft x W_2_ft = __8_ft² 2. Flow rate:100ft/minute x __8__ft² =__800__ft³(CFM) Maximum CFM for the filter is +20% of min CFM. So this filter requires a blower that blows 800CFM at .5 inWG of static pressure (not including the prefilter). Any filters that we use as prefilters will also produce static pressure, many standard 1" furnace filters usually have a resistance of around .4 inWG of static pressure, this needs to be added to the static pressure of your HEPA. Let's add static pressure to the equation: 1. HEPA measurements:L_4_ft x W_2_ft = __8_ft² 2. Flow rate:100ft/minute x __8__ft² =__800__ft³(CFM) Maximum CFM for the filter is +20% of CFM. 3. Static Pressure:HEPA SP _.5___+ prefilter SP_.4___= .9" W.g (SP) Using these simple equations we can see that this filter requires a blower that is minimum 800CFM - max 960CFM @ .9 inWG (SP) to achieve 100ft/min. Step 2: The BlowerNow blowers have charts of their own, here's an example:  As you can see on the left hand side of this chart they've listed the static pressure, on the right in bold they show the CFM at the corresponding SP. We can see that this particular blower pushes 360CFM @ .8" SP....this blower is not strong enough, keep looking. Here's an example of another type of blower chart:  This chart shows a blower (top line) that is 911CFM @ .9 inWG, this blower will match the above 2ft x 4ft filter Step 3: ApplicationNow do it for your own filter, just plug in your own numbers and you'll be gtg. The combined answers you get from line 2 and line 3 will give you the specs for your blower, as shown below. 1. HEPA measurements: Length___ft x width___ft = ___ft²
2. Flow rate: 100ft/minute x ____ft² =____ft³(CFM) Maximum CFM for the filter is +20% of minimum CFM.
3. Static Pressure: HEPA SP ___+ prefilter SP____= ___ "W.g SPBlower match = 2. ____CFM@ 3.____"SP A note on "clogging the intake"Blocking the air intake of your blower excessively will put unnecessary strain on the motor and will likely effect it's lifespan/efficiency. Chocking the intake can be done within reason however I suggest getting as close as possible to the proper output without choking the intake. No need for six prefilters to close the gaps of incomplete planning. Here's an interesting HVAC video that clearly illustrates pressure drop in filters. An average 1" pleated furnace filter will produce ~ .4 to .5 inWG in pressure drop. Thanks to Sandman420 for this laminar flow smoke test video: I hope this write up clearly illustrates the relationship between filter, blower, and their respective charts. Happy building. The above filter and blower match up were used in this build
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PinkStormtrooper
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26679448 - 05/18/20 05:36 PM (3 years, 8 months ago) |
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math. brain. mushy. help. what if the motor blower is rated for a high static pressure like it says 1000CFM at 8" pressure. I can't math can you please show how to apply that?
-------------------- "say, you got a little astroglide on your moustache"
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Stipe-n Cap


Registered: 08/04/12
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You buy/choose the filter first then match the blower, not the other way around.
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PinkStormtrooper
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Re: So you're building a flowhood? [Re: Stipe-n Cap] 3
#26679547 - 05/18/20 06:18 PM (3 years, 8 months ago) |
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-------------------- "say, you got a little astroglide on your moustache"
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gizmo1



Registered: 06/15/11
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Finally got tired of us noobs asking questions huh p9
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: gizmo1]
#26679675 - 05/18/20 07:21 PM (3 years, 8 months ago) |
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Lol, not at all. Just thought this would have been helpful to read when I was trying to wrap my head around it for the first time. I find templates helpful, hopefully someone else will as well.
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MH5109
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Re: So you're building a flowhood? [Re: gizmo1]
#26679677 - 05/18/20 07:22 PM (3 years, 8 months ago) |
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Fungi perfecti has a pretty good list with common filter sizes and blower pairs.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: MH5109]
#26679679 - 05/18/20 07:23 PM (3 years, 8 months ago) |
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Yeah but they don't tell you what the product numbers are or how to match them if you're buying them from another source. They also don't show you the charts. If you live in a country other than the US and cannot order from them...
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gizmo1



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26679704 - 05/18/20 07:41 PM (3 years, 8 months ago) |
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Quote:
p9hu7 said: Yeah but they don't tell you what the product numbers are or how to match them if you're buying them from another source. They also don't show you the charts. If you live in a country other than the US and cannot order from them...
Thats pretty damn foul.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: gizmo1]
#26679708 - 05/18/20 07:43 PM (3 years, 8 months ago) |
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Yeah that Stamets character is pretty shifty. They use their own product numbers for the blowers.
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gizmo1



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26684310 - 05/20/20 09:01 PM (3 years, 8 months ago) |
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So p9. You have been helping me alot answering my questions about FH. I get how to pair the blower and HEPA for the most part. The part I really don't understand is choosing the HEPA. What kind and depth is ideal? Wth is a mini pleat? We talked a little about it in cult general discussion the filter I had picked out was 99.99 but at .3 microns. Ideally I would want one that does 99.97 at .1 micron? I believe you said something like that. Is a deeper filter better than a shallow one? Does it matter? Also is the filter material important? Would it be better to have one framed in metal than wood? Where is it ok to skimp out on filter? There is alot of stuff about pairing filter and blower, not so much about choosing the filter itself.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: gizmo1]
#26684440 - 05/20/20 10:27 PM (3 years, 8 months ago) |
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Those are great questions that 100% need answering when considering a filter. They've been covered soo many times by people far more expert than myself that I didn't cover it in my post, I haven't come across any kind of math template so I saw a potential niche that I could personally fill that would be somewhat original. Having said that I'm happy to weigh in on what you've mentioned...
The depth of the filter isn't really important in terms of what is better versus worse. Thickness plays a role in the amount of static pressure produced by the filter and that will have an impact on what blower you choose in the end. What I believe is important however is the efficiency of the filter, for example 99.95 versus 99.99 etc. I think that it comes down to availability of resources. The higher the efficiency the better obviously, .1 as apposed to .3, steel frame is preferred to cork for durability but cork will work and has worked for people in the past. Cork framed filters are always the cheaper option and the price will reflect upon it's efficiency.
Ultimately The question comes down to what can you afford and what is available where you live. A 99.95 cork framed 12" thick HEPA will definitely work(also whether the HEPA is pleated or metal fin) and can make for an affordable build for those who don't have a ton of disposable income for mycology. My recommendation however, should you have the available funds and resources would be to invest in a metal framed HEPA with a slim build. Metal for the previously mentioned reasons and slim due to the fact that all of the newer high efficiency filters just come that way but also because of the reduced static pressure.
These are questions you'll have to ask yourself, do you have the money to invest in a Cadillac or do you want to be conservative and go with the Prius? Both will get you from A to B but with some obvious differences.
Now I'm by no means an HVAC professional, so should anything I've said be inaccurate I hope someone will step in and set it straight. Hopefully that's at least slightly helpful.
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gizmo1



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26684489 - 05/20/20 10:59 PM (3 years, 8 months ago) |
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Appreciate you p9 always answering my noob ass FH questions. I'm definitely a Cadillac guy. More of a 1987 Cadillac with a flat tire kinda guy though.
Edited by gizmo1 (05/20/20 11:04 PM)
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Stipe-n Cap


Registered: 08/04/12
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Re: So you're building a flowhood? [Re: gizmo1]
#26684498 - 05/20/20 11:02 PM (3 years, 8 months ago) |
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Lol, but it's still a Caddy ; )
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gizmo1



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26684502 - 05/20/20 11:05 PM (3 years, 8 months ago) |
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In all of its glory my friend.
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mushpunx
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Re: So you're building a flowhood? [Re: Stipe-n Cap] 1
#26684534 - 05/20/20 11:19 PM (3 years, 8 months ago) |
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Nice write-up!
Quote:
p9hu7 said: Yeah that Stamets character is pretty shifty. They use their own product numbers for the blowers.
Yeah so people don't go out and buy them for a fraction of their price I think I paid $80 + free shipping for mine brand new.
In case anyone is wondering the 549CFM (@ free air) blower Fungi Perfecti sells is the 1tdt2. It pushes 360CFM @ .8sp , *240CFM @ 1.0sp (*as far as I can tell reading the pixilated graph).
It works well with a 12 x 24" filter with an SP of 0.8 . It is the blower they use in their Series 1 FH , I used it on my new 12 x 24" hood.
--------------------
 Amateur Mycologists United AMU Q&A
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Stipe-n Cap


Registered: 08/04/12
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Re: So you're building a flowhood? [Re: mushpunx]
#26684554 - 05/20/20 11:28 PM (3 years, 8 months ago) |
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Yes indeed, it's on my series 1. Yeah, FP intentionally obfuscates any identifying model numbers so that people don't know how to find the simplest of items from their site...like that fuckin scalpel, I want one but I'm definitely not buying one from them. Can't use "Paul's favorite scalpel" as search criterion.
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mushpunx
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26684607 - 05/21/20 12:01 AM (3 years, 8 months ago) |
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Quote:
p9hu7 said: Yes indeed, it's on my series 1. Yeah, FP intentionally obfuscates any identifying model numbers so that people don't know how to find the simplest of items from their site...like that fuckin scalpel, I want one but I'm definitely not buying one from them. Can't use "Paul's favorite scalpel" as search criterion.
I hear that man! I buy from them sometimes for things that I think are priced fair enough. Small stuff. I did get a HEPA from them before
I actually like the other scalpel they have, it's not Stamet's favorite I guess but you never have to change the blade and it's easy to clean. If you find the other one tho let me know!

Hey I don't want to derail you but what do you use for a prefilter on your Series 1? According to the chart adding more than 0.2 SP will drop the flow below 200cfm
Edited by mushpunx (05/21/20 10:42 AM)
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: mushpunx]
#26685102 - 05/21/20 08:09 AM (3 years, 8 months ago) |
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I don't use a prefilter on it.
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mushpunx
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26685386 - 05/21/20 10:37 AM (3 years, 8 months ago) |
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Quote:
p9hu7 said: I don't use a prefilter on it.
Word. Thanks! It should be 360 CFM without one and it's a strong flow. Right now I put one on when I'm scrubbing the room.
--------------------
 Amateur Mycologists United AMU Q&A
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fungusmuncher
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Re: So you're building a flowhood? [Re: mushpunx]
#26724767 - 06/06/20 06:27 PM (3 years, 7 months ago) |
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Having a hard time wrapping my head around this, will this filter work? https://www.amazon.com/gp/product/B074KMNZW3/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 ; I just don't want to buy it and not be able to match a fan. I asked the seller about a flow rate chart but haven't heard back yet.
edit: I found some info on the companies website that says "125 fpm @ 1.0 in w.g". So at 100 fpm would it be .8 in w.g? So would I need a fan that blows 400cfm @ 1.2 in w.g with the prefilter included? I don't even know if this makes sense, not making much to me. Any help would be appreciated, don't know if I should grab one before they are gone.
Edited by fungusmuncher (06/06/20 08:15 PM)
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Stipe-n Cap


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That will work in a pinch 
125fpm is fine, just as long as it's 100fpm minimum and not unreasonably high like 500fpm or something, ballpark is fine. Grab that filter up and add .4SP for the prefilter if you're using a standard 1" thick furnace filter. If your prefilter doesn't have a label with it's SP just look it up on their site if you want to be more accurate.
I don't know what it would be at 100fpm because I don't have the chart so just assume 1.4"SP @ ~400+CFM will do.
Edited by Stipe-n Cap (06/06/20 10:27 PM)
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26725789 - 06/07/20 07:07 AM (3 years, 7 months ago) |
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Thanks for the help, it's starting to make sense I think. I noticed a previous buyer posted a picture of the spec sticker. It says Resistance: .7 in w.g. Test Flow: 500cfm.
So does that mean that when 500cfm is pushed through the filter the static pressure is .7 in w.g?
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micelio
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26725929 - 06/07/20 08:37 AM (3 years, 7 months ago) |
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I see many of people buying the 12 inch deep filter and thinking they'll get laminar flow.
Anyone trying to achieve laminar flow should buy the 6 inch deep filter.
The 12 inch deep filter has half the resistance as the 6 inch.
3 inch deep filter has twice the resistance as the 6 inch.
The 6 inch with the right blower you can achieve the 1.0 inch of static pressure in the plenum area of your flow hood. Without this pressure the air will not exit your filter at the same parallel velocity therefore the resultant would be turbulent air that could vortex contaminates into your work area..
GO FOR THE FLOW.. THINK LAMINAR
my two cents...
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fungusmuncher
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Re: So you're building a flowhood? [Re: micelio]
#26725984 - 06/07/20 09:06 AM (3 years, 7 months ago) |
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The filter I was looking at is 5 7/8 thick. Just trying to figure out the numbers to match a blower.
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micelio
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This Is the blower you need. It's a little over size but that's a good thing. You can control the airspeed by restricting the airflow at the intake of the filter with wax coated cardboard or sheet metal.
https://www.grainger.com/product/DAYTON-OEM-Blower-1TDU2
Dayton 1TDU2 This Is the blower Fungi Perfecti supplies with their 2x2x5.8 laminar flow hood.
I assume It's the 2'x2' your looking at?
E-bay has this blower.. https://www.ebay.com/itm/NEW-Dayton-1TDU2-Blower/293602809265?hash=item445c1755b1:g:ucIAAOSwPGNe2Uah
Edited by micelio (06/07/20 09:37 AM)
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fungusmuncher
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Re: So you're building a flowhood? [Re: micelio]
#26726206 - 06/07/20 10:37 AM (3 years, 7 months ago) |
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Thanks, that is the blower that I was looking at. So would I build it then test the flow with an anemometer? Then restrict the intake until the flow is around 100fpm?
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26726311 - 06/07/20 11:18 AM (3 years, 7 months ago) |
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Quote:
micelio said: I see many of people buying the 12 inch deep filter and thinking they'll get laminar flow.
Anyone trying to achieve laminar flow should buy the 6 inch deep filter.
The 12 inch deep filter has half the resistance as the 6 inch.
3 inch deep filter has twice the resistance as the 6 inch.
The 6 inch with the right blower you can achieve the 1.0 inch of static pressure in the plenum area of your flow hood. Without this pressure the air will not exit your filter at the same parallel velocity therefore the resultant would be turbulent air that could vortex contaminates into your work area..
GO FOR THE FLOW.. THINK LAMINAR
my two cents...
You can have laminar flow with 12", many cabinets utilize 12" filters. Are you suggesting that anything other than 6" is ineffective?
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micelio
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26726378 - 06/07/20 11:44 AM (3 years, 7 months ago) |
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You can get laminar flow with the 12 inch deep filter. remember the 12" deep has half of the resistance as of the 6" deep.
Without resistance you've never build pressure in the plenum. Resistance Is your friend.. Without pressure In the plenum the air from the blower would tract to the area of less resistance. That would result to turbulence In the work area.
12 inch deep hepa filters deliver a high rate of volume, they're good for keeping rooms supplied with sterile air like hospital and labs...
For work station flow hoods the 6 inch deep filter Is more practical.
I think you did an excellent job on this thread I am sure It'll help many of people out. I have this thread bookmarked.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26726395 - 06/07/20 11:52 AM (3 years, 7 months ago) |
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Yes you're right, the filter needs to generate resistance in order to build a plenum of pressurized air behind the filter to achieve uniform flow across the filters surface. Could you provide a source that clearly illustrates that the minimum requirement is 1" W.g, please.
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micelio
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26726500 - 06/07/20 12:28 PM (3 years, 7 months ago) |
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Before electronics water gauge was made out of a glass tube in the shape of a U... one end of the tube mounted inside the plenum and the other section mounted on the outside where you can get a visual of the U. The bottom of the tube was filled with water. when the plenum was pressurize the water level would rise in the tube. If It rises one inch you would have 1 inch of static pressure or 1 inch wg.
With an Anemometer you can see If your getting the same constant airspeed throughout the face of your filter and at what wg.
What is laminar air flow? Laminar airflow is defined as air moving at the same speed and in the same direction, with no or minimal cross-over of air streams (or “lamina”).
By contrast, turbulent flow creates swirls and eddies that deposit particles on surfaces randomly and unpredictably.
Edited by micelio (06/07/20 12:30 PM)
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26726519 - 06/07/20 12:38 PM (3 years, 7 months ago) |
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Yes but but that doesn't clearly articulate that laminar flow cannot be achieved below 1"W.g. If what you're saying is that 1" of resistance is required as a minimum to create laminar flow then there must be an engineering chart to represent this. Free air is obviously insufficient but at what point has enough friction been generated to build a sufficient plenum to create uniform flow. I doubt that it's 1"w.g but the burden of proof is on you, I'd be very interested to know, not only that but that information would be valuable to this thread.
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micelio
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Re: So you're building a flowhood? [Re: micelio]
#26726542 - 06/07/20 12:44 PM (3 years, 7 months ago) |
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Oh..! I forgot to mention and this Is my opinion.
Laminar flow Is not like a light switch you turn and off at 1 sp./wg.
I believe you can have laminar flow at 0.8 static pressure and It just gets cleaner and more define as the pressure increases.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26726545 - 06/07/20 12:45 PM (3 years, 7 months ago) |
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Oh my.
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micelio
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Re: So you're building a flowhood? [Re: micelio]
#26726562 - 06/07/20 12:52 PM (3 years, 7 months ago) |
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I love laminar flow..
Why Laminar Flow is AWESOME
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Stipe-n Cap


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Quote:
fungusmuncher said: The filter I was looking at is 5 7/8 thick. Just trying to figure out the numbers to match a blower.
Thickness is irrelevant, follow the steps above and don't over think it. Thickness wasn't included in the template for a reason.
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micelio
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Quote:
fungusmuncher said: Thanks, that is the blower that I was looking at. So would I build it then test the flow with an anemometer? Then restrict the intake until the flow is around 100fpm?
What allot of people do Is use a bic lighter at about 5 inches from the filter.
You want the flame to be at 45 degrees angle. If the flame blows out choke off the intake a little more..
You know It's not an exact science thing.
Some like It fast and some like It slower. It's a preference thing.
The anemometer Is not necessary.
You'll find yourself having so much fun working in front of your hood.
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fungusmuncher
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Re: So you're building a flowhood? [Re: micelio]
#26731646 - 06/09/20 02:40 PM (3 years, 7 months ago) |
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Damn the 1tdu2 seems like overkill for a 24x24. I see people building a 48x24 with the same blower. The label on the filter says the resistance is .7 in w.g, with a prefilter that would make it 1.1. At 1.1 in w.g the 1tdu2 will be around 900cfm, more than double the required airflow.
Or am I looking at this wrong?
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Gan
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Yo p9, you seem to know your shit about filters so you care to clear something up for me?
I just got a 24x36 HEPA from FP (got tired of looking and just bit the bullet). I asked for them to provide me with a spec sheet for the filter. Instead they either dodged the questions or didn't understand it and instead replied with this: "The recommended CFM for the 36x24 HEPA filter is 896. This is the minimum requirement for proper filtration."
What exactly does that mean? Does that mean your blower has to put out at least 896 CFM on the backside of the filter to provide proper filtration? Or does it mean something crazy like you have to have 896 CFM coming out the frontside of the filter for proper filtration? Cause of course that'd be too fast for my size filter.
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micelio
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Re: So you're building a flowhood? [Re: Gan]
#26731933 - 06/09/20 04:42 PM (3 years, 7 months ago) |
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Stipe-n Cap


Registered: 08/04/12
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Re: So you're building a flowhood? [Re: Gan]
#26732263 - 06/09/20 06:26 PM (3 years, 7 months ago) |
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Quote:
Gan said: Yo p9, you seem to know your shit about filters so you care to clear something up for me? I asked for them to provide me with a spec sheet for the filter. Instead they either dodged the questions or didn't understand it and instead replied with this: "The recommended CFM for the 36x24 HEPA filter is 896. This is the minimum requirement for proper filtration."
What exactly does that mean?
It means that they're a group of underhanded and dishonest assholes. They knew exactly what you were asking but intentionally avoided giving you the information because it would allow you to purchase a blower elsewhere. Unfortunately I don't know what the chart has to say about the static pressure produced by this specific filter so unfortunately you will have to take their word for it and buy whatever blower they've matched to that particular filter.
They won't provide details about the blower either, I've mentioned this in a previous comment. I would recommend that people find a more reputable source for parts however it's already too late for you, now you're stuck with whatever they give you, unfortunately. Your hood will function as intended, it's just super tedious to deal with dishonest people that pretend to be mycological messiahs.
Paul can go fuck his Amadou hat.... But if you apply this formula then you can at least determine what CFM your blower would require, that much is in your control:
1. HEPA measurements: L_3_ft x W_2_ft = __6_ft²
2. Flow rate: 100ft/minute x __6__ft² =__600__ft³(CFM) Maximum CFM for the filter is +20% of min CFM.
So you would need between 600-720CFM. Unfortunately you don't know anything about the filters static pressure so you can't go any further. I'm not sure how they came up with that number they gave you  Maybe they should start using my template, lelz.
Edited by Stipe-n Cap (06/09/20 07:06 PM)
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Gan
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26732447 - 06/09/20 07:33 PM (3 years, 7 months ago) |
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Oh for sure. It's ridiculous they don't give out any of the spec information. I guess it gives them a monopoly of some sort. I found a fairly decent source for filters if anyone happens upon this thread. Only thing is they have a 4 week lead time. But they're fairly priced imo.
I actually went ahead and ordered the Dayton 1TDU2. I know it'll work with that filter, because literally the blower FP recommends with their 24x36 filter is a 1TDU2, except it's called the Universal Blower or something on their site. It costs $100 more for "their" blower than the 1TDU2 I got off Amazon. But obviously it's the same blower. It should be illegal to be honest. Like I said in another thread, only reason I got a filter from FP was because it would be here in a week, versus 4-6 weeks for other sources I could find. But yeah, it's fucked that they purposefully avoid questions. Glad to know I'm not the only one with no clue what they're talking about. I just wanted to make sure. I appreciate it man!
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: Gan]
#26732488 - 06/09/20 07:48 PM (3 years, 7 months ago) |
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The reason for such a long lead time is that these companies often build to order, FP has them pre-built and kept in stock. Congrats on the hood though, I can't live without one.
That's exactly why they obfuscate product numbers, their's is more expensive and they don't want you to source a cheaper product elsewhere. I suppose that's business but still, it seems underhanded how they go out of their way to hide these things. Withholding the data sheets for the products that they sell should be illegal.
Edited by Stipe-n Cap (06/09/20 07:58 PM)
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Gan
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26732541 - 06/09/20 08:03 PM (3 years, 7 months ago) |
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Yeah that's what I thought. If I hadn't been going crazy from searching eBay with no luck for the last month, I would've said whatever and waited the 4 weeks no problem. Especially for the price.
I'm excited for the hood. Been doing this for a few years now and wanted a flow hood since I started. Got an unexpected bonus at work so I said fuck it, I'm getting one lol. This is the only hobby I really spend any money on (except guitar; we don't talk about how much I spend on that.... lol) so I thought I'd treat myself. Hoping to have it up and running by next weekend. I'm trying to figure out if I need to throw a coat of varnish/lacquer on it to prevent molding. You have any issues with molding and does your hood have a finish to it to prevent that?
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: Gan]
#26732562 - 06/09/20 08:09 PM (3 years, 7 months ago) |
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I'm not sure that it would mold but you should probably coat it for longevity, plus it would look sleek af with some stain/varnish. I haven't put my 24x48 together yet but when I do I'm definitely going to put a coating on it. I'm getting a farm up and running so I'm waiting for my lab build to be completed before building the box.

As you can see I've also dealt with FP in the past, my series 1 works well in my interim "lab" set up in a 4x4 grow tent.
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Gan
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26732605 - 06/09/20 08:23 PM (3 years, 7 months ago) |
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Haha I feel like you deal with FP once then avoid them after that.
And yeah I'm just debating whether to finish the wood after assembly or before. If I do it before, the wood glue wont stick so I'll have to use something that works worse. If I do it after, the cut edges (and therefore the joints) wont be finished so I run a risk of mold finding it's way into joints and speculating. However, most people and TC's here have said they have no issue with mold as long as they don't get their FH wet.
I have a lot to learn about what to do/not to do and use differences between SAB and FH
Good luck with the farm man! Hope it goes well for you. And thanks for taking a little time to help
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: Gan]
#26732635 - 06/09/20 08:31 PM (3 years, 7 months ago) |
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Quote:
Gan said: And yeah I'm just debating whether to finish the wood after assembly or before.
Oh, I misunderstood.
Quote:
Gan said: Good luck with the farm man! Hope it goes well for you. And thanks for taking a little time to help
Thank-you sir, and yeah man, anytime.
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Stipe-n Cap


Registered: 08/04/12
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Quote:
fungusmuncher said: Damn the 1tdu2 seems like overkill for a 24x24. I see people building a 48x24 with the same blower. The label on the filter says the resistance is .7 in w.g, with a prefilter that would make it 1.1. At 1.1 in w.g the 1tdu2 will be around 900cfm, more than double the required airflow.
Or am I looking at this wrong?
In order to answer your question I'd need to see the flow chart and the specs for your blower.
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736215 - 06/11/20 08:06 AM (3 years, 7 months ago) |
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The seller of the filter sent me this, the yellow line is the filter I was looking at.

This is the chart for the blower.
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Stipe-n Cap


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Ok so this one takes a little fuckery because you have to convert m³/h to ft³/m which can be done here:
https://www.convertunits.com/from/cubic+m/hr/to/cfm
And you also have to convert Pa to inch W.g here:
https://www.google.com/search?q=pa+to+inch+w.g&oq=Pa+to+W.g&aqs=chrome.1.69i57j0l2j69i60.8829j0j7&client=ms-android-samsung-ss&sourceid=chrome-mobile&ie=UTF-8
So when you take the orange line straight down it will intersect at ~250 m³/h which = 147 ft³/m(CFM), 147CFM intersects with 50 Pa which is .2" W.g.
So the resistance of your filter is .2" @ 147CFM which is pretty low resistance and may be difficult matching a blower to.
Now for the blower.
Each one of those notches along the CFM line represents 65 CFM, so moving up 7 notches is 455 and the SP is well over 1.5". This blower will push over 1k CFM at .2"
I wouldn't match these two together.
Have you purchased this filter?
Edited by Stipe-n Cap (06/11/20 08:53 AM)
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736270 - 06/11/20 09:04 AM (3 years, 7 months ago) |
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Yes I did purchase the filter, it actually just arrived in the mail. I'm not sure if the seller understood my question, I could barely understand his english. Here is a picture of the label on the side of the filter.
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Stipe-n Cap


Registered: 08/04/12
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Ok so now you need a blower that will blow 400 - 480CFM at .2+ prefilter, so probably ~.6
Best candidate would be the Dayton 1tdt2 Pictured here:

Conveniently showcased in th OP which pushes 435 @ .6
https://www.grainger.com/mobile/product/DAYTON-OEM-Blower-1TDT2?searchQuery=1tdt2+&searchBar=true
Edited by Stipe-n Cap (06/11/20 09:36 AM)
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736350 - 06/11/20 09:35 AM (3 years, 7 months ago) |
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Ok I must be looking at this wrong. I thought I would need a blower that would do 400~500 cfm at ~.9 or possibly more depending on the prefilter. I'll start looking around for a different blower. Thanks for all your help man.
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Stipe-n Cap


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Np...how did you come up with .9?
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736355 - 06/11/20 09:38 AM (3 years, 7 months ago) |
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The .7 on the label plus .2 from a prefilter.
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Stipe-n Cap


Registered: 08/04/12
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Oh, yeah I just noticed that. Super weird that the label doesn't match the flow chart. The label clearly states the test flow is 500ft³/m but the flow chart has it starting at 500m³/h. I'd clear that up with someone because it's a big difference.
500m³/h is only 294CFM
According to this flow chart the label should read:
Resistance: .4 in W.g test flow: 294CFM
Edited by Stipe-n Cap (06/11/20 09:55 AM)
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736389 - 06/11/20 09:51 AM (3 years, 7 months ago) |
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I don't know if I trust the flow chart. It took 3 or 4 communications before the ebay seller sent that to me and said "I think this is what you need". I've been trying to contact the manufacturer but no luck yet. I have the 1tdu2 on the way right now but not sure if I should cancel the order.
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Stipe-n Cap


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Oh boy. Yeah cancel that order until it's settled. It seems more likely that they sent you the wrong chart so the blower won't match. If the chart is correct then get the 1tdt2, if the label is correct which seems much more likely, you'll need a 500CFM blower @ ~ 1.1" SP
The Dayton 1Tdu2 pushes 1040 CFM @ 0.8"SP and will be far over powered.
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micelio
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736527 - 06/11/20 10:41 AM (3 years, 7 months ago) |
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fungusmuncher
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If I'm looking at this correctly, and going by the label on the filter. The 1TDT2 would only push around 200cfm at 1.1in wg.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26736579 - 06/11/20 10:57 AM (3 years, 7 months ago) |
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That was my original recommendation if his flow chart was correct, it will be under power by a long shot if the label is correct.
Go with the label.
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736586 - 06/11/20 11:00 AM (3 years, 7 months ago) |
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Yea I'm sizing one up for the label right now but having a hard time finding one that does 400-500cfm at 1.1. Most blowers drop off fast when the pressure is that high.
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Stipe-n Cap


Registered: 08/04/12
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Yes I had the exact same problem, that's why I went with a centrifugal fan. There doesn't seem to be a middle ground with squirrel cage fans, they do low SP and very high SP with high CFM.
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micelio
Song of Silence


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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736688 - 06/11/20 11:56 AM (3 years, 7 months ago) |
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I know allot of people are not happy with Fungi Perfecti.
But there's a reason why they're using the Dayton 1TDU2 for their 24"x18"x5.8 to the 24"x36"x5.8"..
I'm happy with both my filters with the 1TDU2.
I have to restrict the air flow at the Intake on both filters to get the right airspeed for my liking. No big deal.
The more I restrict the flow the less amperage I consume. My 2 1TDU2 are fairly quiet units. I got mine off of e-bay.. 6 years ago..
They're going for 260.00 with free shipping now. at e-bay
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26736729 - 06/11/20 12:20 PM (3 years, 7 months ago) |
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He needs 500CFM blower @ ~ 1.1" SP

The 1TDU2 sheet is posted above, as you can see the 1TDU2 is over powered. FP is fucked, maybe it's appropriately matched to their filter (which they will not supply the flow chart for) but it isn't the appropriate match for the above mentioned filter.
As I mentioned in the OP:
Quote:
Blocking the air intake of your blower excessively will put unnecessary strain on the motor and will likely effect it's lifespan/efficiency. Chocking the intake can be done within reason however I suggest getting as close as possible to the proper output without choking the intake. No need for six prefilters to close the gaps of incomplete planning.
The 1TDU2 has almost twice the required CFM.
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736839 - 06/11/20 01:14 PM (3 years, 7 months ago) |
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I came across this inline fan that might fit the bill. at 1.0 it pushes 468cfm and at 1.25 it's at 408cfm. I read somewhere that inline fans don't work well for this application so I've been focusing my search on squirrel cages fans but I think this might work.
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Stipe-n Cap


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Inline fans work just fine. That fan looks gtg
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micelio
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I did a search on vtx800.
I like educating myself and always looking for a better way and cheaper.
Flow Hood Build: Centrifugal fan vs portable blower
https://www.shroomery.org/forums/showflat.php/Number/24439330
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26737008 - 06/11/20 02:55 PM (3 years, 7 months ago) |
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Not sure what you're getting at? Are you saying that an inline centrifugal fan won't work? Many people on this site use one, check out edmunters build.
Don't use a portable blower though, this should be common sense.
https://www.shroomery.org/forums/showflat.php/Number/26187961/fpart/1/vc/1
I'd say his grows have turned out just fine.
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micelio
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26737144 - 06/11/20 04:04 PM (3 years, 7 months ago) |
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No I'm not saying It won't work. by reading other people post you can get the pro and cons.
The vtx800 Is not cheap That's for sure. check out e-bay.
I read a few reviews on the vtx800 and they're noisy what some say and a few of them say they're quiet.
I have a 6 inch inline, I don't know the brand, I use It for air exchange when growing oysters. It's very noisy.
From what I can see Is they're more expensive than the Dayton 1TDU2.
Then what has cross my mind Is the vortex Issue some are talking about.
My opinion Is there's nothing wrong with be over powered and choking the Intake down with the squirrel cage type blower. I been running my two 1TDU2 for six years now daily and It runs like a sewing machine. Never giving me a problem and somewhat quiet to the ear..
My 2 cents...!
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: micelio]
#26737158 - 06/11/20 04:11 PM (3 years, 7 months ago) |
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To each their own. Mine cost me $1500 so a few hundo seems cheap by comparison.
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26737421 - 06/11/20 06:04 PM (3 years, 7 months ago) |
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Well the 1TDU2 will be arriving tomorrow. I'm thinking I'll return it and buy the vtx800 or even the vtx1000 and dial it back on a controller if needed.
I thought about choking the intake on the 1TDU2 but I would probably have to cut it down by almost 50%. Don't know if that will affect the longevity of the blower.
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Stipe-n Cap


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Good luck on your build, looking forward to the pics.
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fungusmuncher
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26789508 - 06/28/20 10:46 AM (3 years, 6 months ago) |
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Here she is, I'm so damn happy right now I could cry. Doing some testing to try and dial the fan in for optimal flow. The lighter is around 6 inches in the pic with the fan dialed back a bit. Thank everyone here for the help. There is no way I could have done this without the knowledge obtained within these threads of gold. Heading out to look for a taller platform to make sure I'm staying in the flow, my cooling rack is a bit too short. What angle do you guys think the flame should be at and at what distance from the filter?

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Stipe-n Cap


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Nice job, looks like everything worked out well
The lighter works fine and I know what I'm about to say is a tad contentious but if you really want to know what's going on with your flow I'd buy an anemometer, it's only ~$25 or so. You'll get turbulence where the flow drops off from 100ft/min, a lighter won't really tell you with any kind of real accuracy. In a hobby where attention to detail is paramount it seems odd that a lighter flame is held in such high regard when measuring airflow.
Whipe we're talking about your flow rate it may be pertinent to mention your flow will obviously break down due to obstacles creating turbulence as well, so be aware of that when stacking bags or jars in your work space, just because something is in front of the hood doesn't mean that it's necessarily within sterile flow.
Edited by Stipe-n Cap (06/28/20 11:33 AM)
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sandman420
Saint PP



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26789579 - 06/28/20 11:14 AM (3 years, 6 months ago) |
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A $25 anemometer aint worth a cat turd for flowhood measurements. They have a +/- of like 50 fpm which is totally unreliable.
That looks great man dont fuck with it anymore.
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fungusmuncher
rabbit chaser



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26789583 - 06/28/20 11:16 AM (3 years, 6 months ago) |
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Right on I'm looking around for one now, hopefully I can find one local.
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sandman420
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Re: So you're building a flowhood? [Re: sandman420]
#26789593 - 06/28/20 11:19 AM (3 years, 6 months ago) |
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If you are stacking bags or otherwise crowding your flowhood you are not using it correctly that is good advice p9hu7. I know someone going to show me a picture of how they stuff 29 bags in their 24 inch hood by literally building a wall and it "works for them" but guess what that's real stupid and a smoke test would show all of the backwash going in the flow right up the bags butts.
I see Tera Universal has totally ripped off the Baker EdgeGard now that the patent has worn off ehhh? Bastards.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: sandman420]
#26789615 - 06/28/20 11:32 AM (3 years, 6 months ago) |
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Ok,so buy one for $150 then  I haven't used one since sniper course so I honestly don't know what the margin of error is on a low end model. My point was if you want to be accurate then a lighter seems pretty darn analog when compared to a digital instrument.
Good call though sandman, if you purchase a digital instrument be sure to check the accuracy/margin of error first.
I wouldn't worry about it though, you matched your blower and filter correctly so it's gtg
@sandman...yeah you see plenty of commercial and hobby farmers cramming their work area, it's definitely not best practice.
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sandman420
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Re: So you're building a flowhood? [Re: sandman420]
#26789656 - 06/28/20 11:50 AM (3 years, 6 months ago) |
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For all of you friends out there cooling walls of bags in front of your flowhoods and do not have a Baker EdgeGard or aparantly this terra rip off...You are doing yourself a disservice. Bags do not need to be cooled off in front of a flowhood if you are preparing them in a particular way. You may be familiar with "Pasteurs experiment" wherein micro-organisms are unable to travel up a curved neck of a flask to infect a broth

Now if you prepare a bag in the common way of simply filling it up with grain to a certain point and then folding the top down so that it sits on its own top you literally have an inherent filtering system exactly like this.

OK so now you take that same bag and you throw it into a wall in front of the flowhood and suddenly you can not take advantage of this inherent filter because you are forcing air which probably contains backwashed dirty room air all around it.

I have been cooling my bags by simply opening the top of the pressure cooker in regular room air after about 20 minutes after the pressure comes to 0. Let it sit for about 4 + hours to cool a decent amount. Then you can grab them in a certain way by the fold that does not disturb or unravel the top to move them to a tub or a shelf to cool the rest of the way. Then move to hood 1 at a time to inoculate.
Edited by sandman420 (06/28/20 11:55 AM)
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sandman420
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Re: So you're building a flowhood? [Re: sandman420]
#26789667 - 06/28/20 12:02 PM (3 years, 6 months ago) |
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If the anemometer has a fan on it it is totally worthless for measuring a flowhood airspeed. Even a $160 high dollar unit has this for the accuracy
Quote:
± (3%rdg + 40 ft/m)
http://www.extech.com/products/resources/AN100_UM-en.pdf
So 3% + 40 ft a min is totally worthless measurement when you are measuring 90-120 fpm. Like worse than if you just didnt measure it. Only a $500 plus hot wire anemometer is a reliable measurement of these low speeds. So basically just dont worry about it and use a lighter.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: sandman420]
#26789682 - 06/28/20 12:15 PM (3 years, 6 months ago) |
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There's no issue with placing bags or jars in the flow provided it's only 1 jar or bag deep. Once you start stacking them 2+ deep those jars/bags are now in turbulent flow. When I do g2g for example it's much more convenient to have a row of jars lined up against my filter ready to receive grain, the same is true for bags. Otherwise I agree with what you're saying there.
Quote:
sandman420 said: If the anemometer has a fan on it it is totally worthless for measuring a flowhood airspeed. Even a $160 high dollar unit has this for the accuracy
Quote:
± (3%rdg + 40 ft/m)
http://www.extech.com/products/resources/AN100_UM-en.pdf
So 3% + 40 ft a min is totally worthless measurement when you are measuring 90-120 fpm. Like worse than if you just didnt measure it. Only a $500 plus hot wire anemometer is a reliable measurement of these low speeds. So basically just dont worry about it and use a lighter.
Ok, good to know. Thanks.
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sandman420
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Re: So you're building a flowhood? [Re: Stipe-n Cap] 1
#26789690 - 06/28/20 12:18 PM (3 years, 6 months ago) |
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There is absolutely an issue with lining up even a wall 1 bag deep. I guarantee if you made a smoke test like this and ran it around your bags you would be shocked. Look extra hard at 1:46 and 2:45, 5:26 will blow your titties off . I am sorry that I have not been able to convince you of this I have failed.
Edited by sandman420 (06/28/20 12:24 PM)
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: sandman420]
#26789712 - 06/28/20 12:28 PM (3 years, 6 months ago) |
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So you're suggesting that g2g should be done 1 jar or bag at a time? I'm sure you can see how in that case the medicine is worse than the disease.
Excellent video btw, I'm going to add it to the OP actually...and yes I see what you're getting at but there comes a point where expedience outweighs theory. G2g, a2g cannot be achieved with any kind of volume should you be walking back and forth for single jars/bags, not only that but experience teaches us that this practice easily passes quality control. Lining jars in laminar flow, though it produces turbulence yields more than acceptable results, as I'm sure you must be aware. Simply having master and receiving jar in the flow creates turbulence, you cannot do work in your flow without creating turbulence, that's where sterile technique comes into play. Anything against the filter and within the margins of its flow is in laminar flow. The turbulence is created behind the object as visualized in the previously posted diagram.

Edit* by 1 deep I mean I single line in single file along the face of the filter, just to be clear.
Edited by Stipe-n Cap (06/28/20 12:40 PM)
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sandman420
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26789716 - 06/28/20 12:34 PM (3 years, 6 months ago) |
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1 bag at a time is the most I would put in front of a 24" homemade flowhood with no sides but I have done 2 before side by side reliable. You want to leave some space between them. But the way I have my bag sealer set up it is easier to just do one anyway. Could probably do 6-8 jars I bet, but really its just easier if the whole hood is open and you are just working on one thing at a time. Grab a jar, g2g, grab a jar g2g. No big deal why even have more than one at a time. Its crowded and more clumsy. Not much benifit big deal you spun 8 lids at once....
I keep my shelf of bags right next to the hood so I just grab one, unfold, inoc, put on shelf and grab another its not so bad.
And yes theory is not reality all the time. But god damn when reality comes to bite you in the ass it suckkkkkkks my man.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: sandman420]
#26789735 - 06/28/20 12:42 PM (3 years, 6 months ago) |
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Your method is valid, I'm not saying otherwise, what I am saying however is that what I've said is standard practice and has been shown to be effective. To each their own.
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sandman420
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26789779 - 06/28/20 01:00 PM (3 years, 6 months ago) |
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Sorry I was trying to say I was in agreement with that it seems a lot of people are using methods that would be in theory bad practice but have success.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: sandman420]
#26789791 - 06/28/20 01:05 PM (3 years, 6 months ago) |
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Ah, roger.
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: gizmo1]
#26836414 - 07/21/20 03:49 PM (3 years, 6 months ago) |
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Quote:
gizmo1 said: There is alot of stuff about pairing filter and blower, not so much about choosing the filter itself.
Fixed the OP to include more of these details
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TigerStrike
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#27111238 - 12/27/20 07:30 PM (3 years, 1 month ago) |
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OOPS I'm an idiot i was reading through LAGM 20201 AND THIS AS SAME TIME
I know one thing it take a lot of work to keep a thread this busy organized, I am headed to the grocery store to pick up some mushrooms commercially to start a spore print so I am ready to compete Participate this is not a race. Or is it?!?!?!?!?!?!?!?!
Is it true this is a friendly thread where everyone does their own method each post is looked as innovative and welcome? Or is this a competition to really see who will be first to fruits?
Or is it a chill place to grow along with the community at your own pace? I am sure the top 3-4 will have friendly rivalry I am sure the noob growers will do their best and I am sure the expert growers are not gonna do bad on purpose?[/gradient]
Edited by TigerStrike (12/27/20 07:58 PM)
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hazyhorse
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Re: So you're building a flowhood? [Re: TigerStrike] 1
#27946153 - 09/11/22 11:48 PM (1 year, 4 months ago) |
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first off, thank you p9 for the thread. super sick stuff
sorry to kinda necro but
i've gotten pretty tired of working in an SAB & a flowhood sounds like absolute heaven right about now. just wanna make sure i got the math right before i drop a bunch of money.
was probably gonna go with this filter. seems like FP is a little contentious but i could not find a product even remotely close to this by searching around. if anyone has a better HEPA filter plug please lmk, but for the price this seemed like the easiest thing i could buy within my budget.
SP is listed at 1.0 on their website & if i'm doing the math right, it'll need 200-240 CFM to achieve laminar flow @ 1.0 SP? i found this blower (1tdt2) which should work right at 1.0 SP according to this chart. then i saw this comment by mushpunx:
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mushpunx said: In case anyone is wondering the 549CFM (@ free air) blower Fungi Perfecti sells is the 1tdt2. It pushes 360CFM @ .8sp , *240CFM @ 1.0sp (*as far as I can tell reading the pixilated graph).
It works well with a 12 x 24" filter with an SP of 0.8 . It is the blower they use in their Series 1 FH , I used it on my new 12 x 24" hood.
so it confirms what i'm thinking, but i noticed the CFM drops off a lot at 1.2 (like to 120 or something) & adding a pre-filter would obviously raise the amount of CFM i would need by quite a bit so i feel like this would be an issue with the filter i would be using. i noticed you said you don't use a pre-filter, but a lot of the DIY builds & teks i've seen seem to use them. is there any significant drawback to not using a prefilter? the other blowers seem overkill & are quite a bit more expensive, so i'd rather not have to go bigger on the blower if i don't have to, but i also don't wanna build a non-functioning hood. sorry for all the questions, i'm just having a hard time wrapping my head around the build & wanna confirm i have an OK understanding of what i need to do.
-------------------- you're not the first to set foot here, just another =================================== i love glass petris & you can too!! posts i constantly refer back to new to mushroom cultivation?? read this!! ===================================
  🅃 🄴 🄰 🄼 🄲 🄻 🄸 🄽 🄶 🅆 🅁 🄰 🄿
Edited by hazyhorse (09/12/22 02:06 AM)
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: hazyhorse]
#27946369 - 09/12/22 05:05 AM (1 year, 4 months ago) |
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Honestly, for the price of a fan filter unit you can't go wrong going that way instead of a diy build, however:
I've never used a prefilter, I don't really see that it's necessary but as you're aware they add resistance which has consequences greater than not running a prefilter in my opinion. People are just concerned about extending the life of their HEPA filter, your filter should last for years without a prefilter so long as you're not running it in a hay barn or something; I wouldn't worry about it.
That blower mentioned above makes it difficult to add a furnace pre filter anyways, it's a non issue from my perspective.
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hazyhorse
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#27946890 - 09/12/22 01:56 PM (1 year, 4 months ago) |
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the idea of making a DIY flowhood was kind of romantic, but i think you’re right about the FFU being more worth it. after doing a few quick searches it seems to be way more worth it for something like these FFUs since before shipping & buying wood it’s gonna be like $400+ for the filter & blower alone, on top of the fact that these are 2’x2’. im glad there’s some good bang for you buck there at least
thank you for the response about the pre-filter resistances. definitely something to keep in mind if i do ever DIY a hood.
-------------------- you're not the first to set foot here, just another =================================== i love glass petris & you can too!! posts i constantly refer back to new to mushroom cultivation?? read this!! ===================================
  🅃 🄴 🄰 🄼 🄲 🄻 🄸 🄽 🄶 🅆 🅁 🄰 🄿
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Stipe-n Cap


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Re: So you're building a flowhood? [Re: hazyhorse]
#27947103 - 09/12/22 04:47 PM (1 year, 4 months ago) |
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Yeah an FFU has way to many benefits to ignore, building your own is cool I guess but an ffu is much cooler imo.
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Nextcontestant
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#27951822 - 09/15/22 06:05 PM (1 year, 4 months ago) |
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Quote:
sandman420 said: There is absolutely an issue with lining up even a wall 1 bag deep. I guarantee if you made a smoke test like this and ran it around your bags you would be shocked. Look extra hard at 1:46 and 2:45, 5:26 will blow your titties off . I am sorry that I have not been able to convince you of this I have failed.
Wow, great video!!! I've never worked in that type of environment, but learned TONS from that... 'cupping' and the pinky hold. Wouldn't of thought those little things would have a dramatic different outcome.
I have been known to preach: is it skill or equipment that will solve your problem. Video proves if you don't have skill, equipment don't matter.
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