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220w pl-l coco scrog cupboard

Mk3Jetta

Member
What if you were using two fans of different CFMs and the larger of the two(lets say 100cfm) was sucking through a carbon filter and the lesser(40cfm) was in front of the filter acting like an inline fan to boost the 100cfms?????

It something I was thinking of doing in my cab, but that picture is just for a visual.

thoughts?

edit: its not really stacked because of the carbon filter....idk I havent read much about stacking vs not stacking. But if there are three people to come out right away and say dont stack than I'm sure your right on that.
 

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ScrubNinja

Grow like nobody is watching
Veteran
Hey guys I have a seedling poking the soil! :woohoo:

Yeah the problem with direct stacking is, as far as I can tell, the blades are both spinning in the same direction and it's sorta like how a propellor or a wing of a plane works, through pressure. Basically they mess with the pressure of the other blade next to it. Solution is to buy the same fan that spins in a different direction while pumping air the same way. But nobody makes fans specifically for stacking so those would be a chore to find. I don't get it. Anyway, I think as long as they're spaced apart a bit, or seperated by a scrubber, it should work. How far is "a bit" I don't know.

While I don't have any measurement tools, it is important to note that you will/should/might (?) still get some pressure increase with direct stacking. I noticed it, some other stackers here noticed it, and some on the pc threads I was reading noticed it, it's just that using the fan configuration rule (side by side vs inline) you should get twice the pressure, but you won't. And you may well get a decrease. That's my take on it anyway, to be taken with enormous block of salt. I'll be able to assess it all when I finish the new filter with unstacked. I just like to prove things to myself. But I'm used to these fans and they're definitely not audibly struggling or anything, and I'm happy enough with the performance of them stacked. I just need everything to work at full efficiency for when summer arrives.

I have the flu right now, so I hope any of this makes sense. Thanks all for popping in. :)

Edit: Your thing will work. I'd assume the 40cfm is an intake fan, so you'd be right to keep it lesser cfm so it doesn't overflow your filter. In my case I am gonna use the two strongest equal fans because they're both exhaust, kinda, and I don't have to worry about pressures at that stage in the exhaust flow. Initially I used the lesser powered fans pulling because they were external and exposed, the strong louder ones pushing were muffled by filter.
 
C

Cozy Amnesia

Kick ass cab, man! I'm loving everything about it. Congrates on the seedling.
 

Mk3Jetta

Member
Edit: Your thing will work. I'd assume the 40cfm is an intake fan, so you'd be right to keep it lesser cfm so it doesn't overflow your filter. In my case I am gonna use the two strongest equal fans because they're both exhaust, kinda, and I don't have to worry about pressures at that stage in the exhaust flow. Initially I used the lesser powered fans pulling because they were external and exposed, the strong louder ones pushing were muffled by filter.


Actually the 40 and 100 would both be exhaust fans.

The 40 pulling air out of the grow chamber and helping the 100 pull even more efficiently through the carbon scrubber. And the 100 would be outside the cab.
 

ScrubNinja

Grow like nobody is watching
Veteran
Thanks Cozy, it's still the only one so far and has "runt" written all over it, but I'm more excited for that than the Pure cuttings. It's an Australian Blue x Shiva Skunk.



55w + 13w. One 80mm fan inside cab on 4.5v, and the exhaust fans on 4.5v.

About the seedling, this is the Aussie Blue mum:


And this is the Shiva Skunk dad:


This could get interesting, gents. :smoke:
 

ScrubNinja

Grow like nobody is watching
Veteran
Actually the 40 and 100 would both be exhaust fans.

The 40 pulling air out of the grow chamber and helping the 100 pull even more efficiently through the carbon scrubber. And the 100 would be outside the cab.

AH I get what ya mean now. Why not just use two 100's?
 
T

teerull

wow.. I can't believe I haven't taken a look in this thread before!
that's an awesome cab you got going there!

Will be takin' a closer interest now for sure! :lurk:

keep up the good work!

peace,
T:joint:
 

ScrubNinja

Grow like nobody is watching
Veteran
Thanks a lot Teerull. It's not completely finished yet, but it's finally sinking in to me that I have a really awesome little cab here. :) The other day, I wanted to put some wet cloth over the intakes at the back and I thought, oh no, I've just stacked several racks in there, and all the cuttings etc. Then I remembered the sliders and 2 seconds later the job was done. Another thing I like about this over my old tent is that opening the tent was a whole procedure in itself, unzipping 5 zips then trying to keep the door flaps pinned open. This cab is as easy as opening.....uh...a cupboard. :D

My seedling doesn't seem to be developing at all :/

I ordered a set of 3000k bulbs for the hood, and some 6100k bulbs for the 13w fluoro. I hope that's what I ordered anyway. Knowing my luck I'll probably have a desk lamp and a box of christmas lights turn up.

This guy was on my doorstep today :)

 
Scrub, you're going to hate me for this if you haven't discovered it yet but you need to space fans apart when you stack them or it stresses them and ruins the benefit of stacking them at the same time. Made that mistake on a watercooled pc with a couple of really expensive panaflos.. it makes them a lot more noisy too - heard yours whine yet?

It's a nice simple fix though, get an old dead or crappy fan the same size as your working fan, and cut off the bars holding the motor in. Instant spacer shroud, just seal it with some silicon at the mating faces. It'll work a lot better.. nice cab anyways, going to to the PL-L thing meself - they're cheap here in the UK.
 

ScrubNinja

Grow like nobody is watching
Veteran
Hey Captain, thanks for dropping in. We did go through this a few posts back on the previous page if you missed it. And no, I don't hear a whine, it's in my living room right now getting drowned out several times over by a PC, although yes they were very loud on 12v, way louder than I was expecting and yeah very whiney now I think of it. I have a theory since I'm running on reduced volts, the whole air interference between the blades thing doesn't come into play to any noticeable degree? I also used 3 washers between each fan on each bolt so maybe that helps a little. When I was doing the recent reading on fans, someone said the "blank" fan as a spacer won't work. This is so confusing.

But yeah, I do concede that it's not a good idea to stack standard computer fans directly though! I'll be rebuilding the whole filter unit and trying to get it working with unstacked fans cos in summer they may well be on 12v. I've even been considering just re-using the old filter I already built for the tent, it's still hanging in place, and use the westaflex mixed flow fan I was using with that. It cooled and scrubbed a similar wattage well. I'm getting sick of building ventilation systems. :puppydoge

Mmmm westaflex...I would box it up and use acoustic ducting this time, on high speed instead of low


Edit: Added an edit on the first post warning about stacking so as not to give the wrong impression. :smile:
 
The blank fan in between two stacked fans does work, we in the overclocking business have used it to make fans draw more robustly through very restrictive radiators on watercooled pcs whilst undervolted for years. The trick is, to seal the joins between the three. If you don't, it won't work. Delta make a fan which is 76mm thick, but uses two 25mm (1") impellers with a gap in between for this exact purpose.

The idea is you can drop the volts down to something like 7-9v and still get more airflow and pressure than one fan, the spacer equalises the pressure between the two, and means that if the blades aren't rotating EXACTLY together, it doesn't matter, they're not fighting each other... which they are when they're stacked directly... in theory a double stack without the spacer will move more cfm unrestricted but in practice it doesn't work like that. In the example i gave before, two fans stacked with a spacer work better than one fan either side of the radiator, in a push-pull setup.

I always use a blank when mounting a fan to anything, even a heatsink. If nothing else it allows the fan to defeat the dead spot in its airflow (fan airflow right in front of the impeller looks like a donut) which is created by the motor in the middle of the fan. You'll get more out of the second fan in the stack, that way, boosting the performance of both.
 

ScrubNinja

Grow like nobody is watching
Veteran
Thanks man, that's awesome info. I would trust your view any day over some random one line post from someone who hasn't qualified their opinion at all! :yes: I appreciate you running through it for me.

The issue facing me now is that I'm planning on using a much shorter "rubbermaid" as the filter unit - one of the black plastic ones made out of thicker, less brittle plastic, which won't allow me to stack (both fans will be horizontal), so I'm simply gonna have to make it work with two unstacked fans. I have a good feeling though. :smile:

Well, thanks again man, very enlightening post. My cuttings are looking good, the seedling is STILL at the exact same stage, just two elephant ears and one of them still hasn't folded right down. Pretty sure this is useless to me. So I soaked 23 of the Aussie Blues just to desperately try and get something out of them since they're not exactly going to increase in viability.
 
here's to hoping for ya matey.. if you can't stack, look for 120x120x38mm fans instead of the 15 and 25mm ones.. they're the best compromise - the YsTech FD1238 is loud as all hell on 12v but is silent at around the 7v mark. 38mm thick fans are much better at overcoming resistance with their air pressure than thinner varieties. Harder to find but much better.

heh 23 seeds.. nice work sah. hope ya get a keeper or two :D
 

ScrubNinja

Grow like nobody is watching
Veteran
lol thanks, none of the 12 AB's I planted originally came up so there's a good chance none of these will. It's just a very special strain to me and I'm also hoping some of the ABs will have duckfoot leaves :D And if none of those come up, I still have enough AB x SH, and AB seeds, to make up another 24 tray and try one last time. The one that did sprout is an AB x SH.
 

mjconfid

New member
I think I'm going to drill the reflector right above the tubes. I have a 6mm drill and I worked out if I drill one hole every 1cm, directly above each tube (4 bulbs = 8 tubes), I'll end up gaining the size of a 120mm hole, approximately, and it should open the flow a lot and I'm confident I won't need fans cooling the bulbs then.

If anyone thinks this could be a bad move, please let me know your concerns, I thank you. :cool:

I say go for it.
Sorry no pics as previously requested - I put my camera in a "safe place" cos' it had pics of my grow on it and can not find it again :mad:. Anyway, I DIY'ed my reflector . In profile, looking along the length of a bulb, it looks like this :

/\/\ Reflector made from cork tiles, covered with aluminium tape.
.0 0 PLL bulb

Each piece of the M shaped reflector is a strip of cork tile , so it was easy to create small gaps above the length of each tube. The angle of the outer (red) strips is shallower than shown above, to better reflect the light around each tube.

Using this reflector, I have no need for fans directed at the bulbs - the plant only gets burnt if the leaves actually touch the bulb.

Another thing to be aware of re. heat from the PLLs (if you haven't used them before), is that the lamps are a significantly hotter when they are brand new. I had 2 brand new bulbs in my cab when I started my grow and it was a lot hotter than now when I have 4 'broken in" bulbs. It took 2-3 weeks for them to get cooler.
 

ScrubNinja

Grow like nobody is watching
Veteran
Cool man! Colour coded ascii art! I like how you've approached it and I don't need much convincing so I'll be going ahead with it. I'll also seal off those side grilles. I forget how many holes I calculated but it was a lot, so I'll have to take it to my buddies. He can help drilling :D I will use the opportunity to cut the holes in the filter box too. I can't do much power tool stuff here.

Didn't realise that about the new bulbs, thanks. I forgot to mention I found the 3000k bulbs online a lot cheaper, I think $11aud free shipping...compared to $45aud from the local lighting store!!! The 4000k's that came in there are definitely broken in - they have dark patches around the bases from the heat! (previous owner)

What's the closest I should get a newly sprouted seedling from a 55w pll bulb? Is 2 inches too close? The temp seems fine at that distance but this seedling just hasn't moved a millimetre, and now it looks to be going necrotic. Maybe it's the IR?
 

Aerohead

space gardener
Veteran
Cool man! Colour coded ascii art! I like how you've approached it and I don't need much convincing so I'll be going ahead with it. I'll also seal off those side grilles. I forget how many holes I calculated but it was a lot, so I'll have to take it to my buddies. He can help drilling :D I will use the opportunity to cut the holes in the filter box too. I can't do much power tool stuff here.

Didn't realise that about the new bulbs, thanks. I forgot to mention I found the 3000k bulbs online a lot cheaper, I think $11aud free shipping...compared to $45aud from the local lighting store!!! The 4000k's that came in there are definitely broken in - they have dark patches around the bases from the heat! (previous owner)

What's the closest I should get a newly sprouted seedling from a 55w pll bulb? Is 2 inches too close? The temp seems fine at that distance but this seedling just hasn't moved a millimetre, and now it looks to be going necrotic. Maybe it's the IR?

2 inches is really close for a seedling, My seedlings grew rapidly @ 9-12 inches from 1 55w 6400k PL-L. Clones need to be 12-14 inches from those bulbs. Can't wait to see this cab up and running full throttle, nice to see you have some plants in there..
 

ScrubNinja

Grow like nobody is watching
Veteran
Thanks once again man. Yup I had it 2 inches so I've moved it away. The clones have been well away all the time. Can you imagine if there was no IC mag? Phew.
 
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