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Stipe-n Cap


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: So you're building a flowhood? [Re: Gan]
#26732263 - 06/09/20 06:26 PM (3 years, 8 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
Wielder of Narya



Registered: 08/26/19
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26732447 - 06/09/20 07:33 PM (3 years, 8 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


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: So you're building a flowhood? [Re: Gan]
#26732488 - 06/09/20 07:48 PM (3 years, 8 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
Wielder of Narya



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26732541 - 06/09/20 08:03 PM (3 years, 8 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


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: So you're building a flowhood? [Re: Gan]
#26732562 - 06/09/20 08:09 PM (3 years, 8 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
Wielder of Narya



Registered: 08/26/19
Posts: 927
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26732605 - 06/09/20 08:23 PM (3 years, 8 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


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: So you're building a flowhood? [Re: Gan]
#26732635 - 06/09/20 08:31 PM (3 years, 8 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
Posts: 7,623
Loc: Canada
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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
rabbit chaser



Registered: 03/07/09
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736215 - 06/11/20 08:06 AM (3 years, 8 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


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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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
rabbit chaser



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736270 - 06/11/20 09:04 AM (3 years, 8 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
Posts: 7,623
Loc: Canada
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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
rabbit chaser



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736350 - 06/11/20 09:35 AM (3 years, 8 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


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Np...how did you come up with .9?
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fungusmuncher
rabbit chaser



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736355 - 06/11/20 09:38 AM (3 years, 8 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
Posts: 7,623
Loc: Canada
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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
rabbit chaser



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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736389 - 06/11/20 09:51 AM (3 years, 8 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


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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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
Song of Silence


Registered: 04/22/14
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Re: So you're building a flowhood? [Re: Stipe-n Cap]
#26736527 - 06/11/20 10:41 AM (3 years, 8 months ago) |
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fungusmuncher
rabbit chaser



Registered: 03/07/09
Posts: 1,068
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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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