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DeckardCain
Stay a while and listen



Registered: 09/22/12
Posts: 236
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Flowhood questions
#26662125 - 05/10/20 10:56 AM (3 years, 8 months ago) |
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I’m in contact with a hepa supplier they have a 24 x 24 filter in metal frame (99.99%) and a wood frame (99.97%) [both are 1.0 sp at 500cfm] .they say using wood frame is easier to make a hood with, but I don’t think I should take the lower of the 2 filters for ease of build . Is that right? Second is for the blower application and according to what I’ve read I need 4 cubic feet times 100 ft/m which would be 400 cfm. I have found the blower Dayton dmd2c889 that does 480 cfm at 1.25 sp (I’d guess a prefilter would add .2 sp ) would that work well? Is 480 too high? Anyone see anything wrong with this? Thanks in advance, and where do people get the wood to build them very stupid question sure I have access to ply wood and all of that but the cuts need to be very precise and I don’t have a table saw or anything like that.
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poisoned
untitled



Registered: 04/17/13
Posts: 1,738
Loc: Yurop
Last seen: 1 year, 3 months
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I'm not in the US, but basically all plywood providers here are offering to cut it up to your needs for a small fee.
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mushpunx
Fungus Punk



Registered: 04/20/14
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Last seen: 10 days, 17 hours
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Re: Flowhood questions [Re: poisoned]
#26662497 - 05/10/20 01:40 PM (3 years, 8 months ago) |
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Take the HEPA in the metal frame. You are building a box around the HEPA, it slides in and out, shouldn't really matter what the HEPA's frame is. Go for the 99.99 , yeah
480CFM @ 1.25sp is not too high no. You can always choke back the blower or stack prefilters if you need to power it down. It's better to go with higher, because the filter will get clogged up over time.
I got my wood at Lowe's, I used 7ply Birch in my latest hood, Aspen on my last one.
I don't own a table saw either, just circular saw. Building a perfect box is hard if you aren't a woodworker. You seal up the edges inside with silicone though so any little gaps won't leak air.
My new hood is in my sig below. There is a grate on the front to protect the filter (they are crazy fragile). I built a smaller hood than my first so I will be able to move it around easy.
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 Amateur Mycologists United AMU Q&A
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DeckardCain
Stay a while and listen



Registered: 09/22/12
Posts: 236
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Re: Flowhood questions [Re: mushpunx]
#26662545 - 05/10/20 02:08 PM (3 years, 8 months ago) |
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I am a skilled trade worker so I’m not lost on wood working but my cuts would never be perfectly straight as to have it seal up, but thanks for all the info,
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mushpunx
Fungus Punk



Registered: 04/20/14
Posts: 13,394
Last seen: 10 days, 17 hours
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Quote:
DeckardCain said: I am a skilled trade worker so I’m not lost on wood working but my cuts would never be perfectly straight as to have it seal up, but thanks for all the info,
Yeah no problem. Yeah without a table saw I had a hell of a time trying to make those cuts perfect. But caulking up the edges on the inside with silicone is usually enough. I haven't had any leaks.

This is my other hood
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 Amateur Mycologists United AMU Q&A
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Stipe-n Cap


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: Flowhood questions [Re: mushpunx]
#26662804 - 05/10/20 05:01 PM (3 years, 8 months ago) |
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Your average 1" thick furnace filter will run at .4"SP so you're going to be gtg. Even without a prefilter you can overshoot the 100ft/min flow rate no problem. I've read that staying within ~20% overage as a rule of thumb but anything within reason should be gtg. Someone over in general cultivation discussion thread said they were going to run 200ft+/min (not sure how that's going to work out for them though)
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gizmo1



Registered: 06/15/11
Posts: 3,831
Loc: FREEDOM
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Quote:
p9hu7 said: Your average 1" thick furnace filter will run at .4"SP so you're going to be gtg. Even without a prefilter you can overshoot the 100ft/min flow rate no problem. I've read that staying within ~20% overage as a rule of thumb but anything within reason should be gtg. Someone over in general cultivation discussion thread said they were going to run 200ft+/min (not sure how that's going to work out for them though)
Was it me? If so I didn't say I was going to run that but that is what it suggests in a cultivation book I have lmao. I don't remember if it was me or if your talking about someone else.
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Stipe-n Cap


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: Flowhood questions [Re: gizmo1]
#26662862 - 05/10/20 05:46 PM (3 years, 8 months ago) |
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I honestly don't know lol, I Just remember someone mentioning something about 2-400ft/m? Something like that. Could have been though, in either case I wasn't being critical.
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gizmo1



Registered: 06/15/11
Posts: 3,831
Loc: FREEDOM
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Lmao I think it was me
kinda makes sense. Book I'm reading now suggests a blower between 200 and 250cfm per cubic foot of filter. Assuming 0.8 static pressure filter and 0.2 static pressure pre filter. Then it has a chart that suggests 800-1000cfm for a 24x24 filter. Since that blower is a 2 speed that supposedly does up to 1360 I figured it would be overpowered and I could dial it back some by blocking the intake.
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mushpunx
Fungus Punk



Registered: 04/20/14
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Last seen: 10 days, 17 hours
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Re: Flowhood questions [Re: gizmo1]
#26662883 - 05/10/20 05:56 PM (3 years, 8 months ago) |
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Quote:
gizmo1 said: Lmao I think it was me
kinda makes sense. Book I'm reading now suggests a blower between 200 and 250cfm per cubic foot of filter. Assuming 0.8 static pressure filter and 0.2 static pressure pre filter. Then it has a chart that suggests 800-1000cfm for a 24x24 filter. Since that blower is a 2 speed that supposedly does up to 1360 I figured it would be overpowered and I could dial it back some by blocking the intake.
You need to check your blower's specification chart to find out what CFM it pushes at .8sp, 1.0sp, 1.2sp etc..
For example my blower is listed as a 549CFM blower. That means it pushes 549CFM @ 0.0SP
So I checked the graph on my blower's specification sheet.
It pushes 360 CFM @.8sp and 240CFM @1.0sp
I have a 12 x 24" filter. So I need 200CFM at the filter's Static Pressure, which I believe is .8SP , so with an added prefilter of .2"SP to that .8sp it's 1.0SP at which my blower will push 240cfm, which is pretty good.
Edited by mushpunx (05/10/20 06:11 PM)
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