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The ultimate beginner's guide to PC FANS

ScrubNinja

Grow like nobody is watching
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You know like goodwill stores and stuff like that? Salvation army? Those kind of places are great.

I had just given up on ever getting a large server case and I was walking out of the last store in town after being told they don't sell cases. The guy stopped me though and asked what I wanted exactly. I said just a big old server case, even secondhand, and he pointed to one on the repair counter and said "take it". I was so happy! Some fucker had ripped me off on ebay when I tried to buy one so it was a very nice turn of events. It's like anything else, seek and ye shall find :)
 
Hey Scrub have you tried any of the Grainger 120v ac axial fans? they come in the same size and cfms as the pc fans. i was just wondering if they are compareable to eachother or not.
 

ScrubNinja

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Yo broski, I haven't even heard of them before but they look pretty decent. I'm basing that only on the first one I found. It's .24 amps but important to note we're not dealing with 12v with an AC fan, so the amps don't matter. The wattage is 20w, and to give you some comparison, my 92mm Delta is 18w. The average cheap fan is gonna be 1 to 4 watts.

Anyway it seems like a nice fan for 49 decibels - they don't mention the pressure rating though so that's uncertain but it's 38mm thick so should be decent. Overall, not a bad fan I would guess.
 

maryjohn

Active member
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Damn makes my deltas look stupid. My cab is wired ac/dc when it could all be ac. Why did I not think of this before? Dph!
 

ScrubNinja

Grow like nobody is watching
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MJ your fans would blow it out of the water, so I think you still made a good choice. It all depends how you look at it. A 12v fan is much easier and more options for a dummy like you or me to speed control, and that's pretty much all there is to it. :2cents:

Woot! Pretty excited. I just improved my system a whole lot. I finally emptied the kitty litter crystals out and put the activated carbon in. This means I went from probably 1.5" or more deep, to one inch or less deep. The kitty crystals were 8 litres. I replaced it with 2 kilograms of fine granulated carbon ("finishing carbon" from a brewing store.)

But probably the main thing is that I rigged up a seperate 7.5v power adapter for the "pull fan" which allowed me to remove the undersized muffler I had on there. This also lets me run the internal "push" fan at 12v quietly inside the filter box/carbon. So now on full steam, the whole unit is a tiny bit quieter than the old setup on 9v, and running far more efficiently. It's at ambient temp exactly and it's much quieter, I can't believe I built a cab that runs at ambient let alone one that does it reasonably quietly. Removing the muffler means I can blow the hot air straight out the window. Having them on seperate adaptors means I can have the "pull" fan on the timer with the lights.

Opening it up reminded me of something I should warn people about again with the carbon screen method - this technique is very dusty and can be hard on fans I suspect. The T'takes are handling it like a champ but they're covered in dust. You may want to investigate a post-filter of some type - I may be doing this.

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Another thing you want to watch out for is tape coming unstuck. I used tape on the edges of my flyscreen to foolproof it, except the tape itself was not stuck right in the corners over time, so that would have been cutting the effectiveness. Of course the answer was more tape :)

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This calls for a celebratory pipe :smoke:
 

maryjohn

Active member
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Heya scrub nice work. Someone recently clued me in - you can wash the carbon. Just rinse and drain in a collander.
 

ScrubNinja

Grow like nobody is watching
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Thanks man it sits now on .2 under ambient, I think that's because my ambient is taken on top of the filter box. Good tip on the carbon yes, I should have done that this time. Luckily the carbon is nowhere near as dusty as the crystals. And you can't rinse those out because they're a dessicant. I put a layer of washed carbon on top but I noticed the dust was coming through after time.
 

maryjohn

Active member
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I would pull it out and wash it. For me it didn't stop coming until I washed and I had to be careful handling it. All over my heat shield! Now I see very little.
 

ScrubNinja

Grow like nobody is watching
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I'ma just gonna use a post filter due to my heavy cannabis habit, lol. I have 20 metres of that frost matting I picked up. I noticed I had a lot of carbon/crystals on the floor of the filter too. I think the next model filter I build will be perfect. I guess we can say then that another thing that carbon-screen'ers should aim for in most circumstances is both a pre, and post filter if you really want to be safe.
 

ScrubNinja

Grow like nobody is watching
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Yeah I mean wash it too, for sure. I'm gonna see how it goes though. I have this whacky theory that the dust is increasing surface area. I put two layers of frost mat and it works great. Dust falling down isn't an issue for me due to the way the vented hood is set up and I leave the fan on full any time I'm inserting/removing carbon etc, so none goes down there.

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You can see my spare bag of carbon in case things get nasty.
 
MJ your fans would blow it out of the water, so I think you still made a good choice. It all depends how you look at it. A 12v fan is much easier and more options for a dummy like you or me to speed control, and that's pretty much all there is to it. :2cents:

so the pc fans are a better option? i will definitely have to go start at the beginning of this thread and check it out more in depth. il be building another mini fridge and was thinking of the 120v dayton fans but if the pc fans are better then i would much rather go that route.
 

ScrubNinja

Grow like nobody is watching
Veteran
Mj, you could have a foot of carbon and 18 pre/post filters if you have enough surface area, that's how it works bro. I agree with you that I should wash it, but it seems to work and it's cheap enough to replace the filter, I can make like 20 for a few bucks. I just mean for someone like an asthmatic, I would wash, pre, and post filter it, because if they've followed along, they'll have area to spare anyway. The first build had no filters, and non washed carbon and I never noticed any dust problem and it was in an enclosed room. Handle each case as it needs to be handled but I'm fine with this as it is. Removing the carbon on a plant half way through flower for however long it takes to scrape up the carbon, wash it, and dry it is not something that appeals to me in this case when I can just use a post-filter. My landlord lives next door don't forget. :)

Hi rhyo. As has been discussed, I don't think intake fans are a good idea, so I feel hesitant to advise you on them. I've also only tried HPS once and gave up on it before I finished (noob issues). A lot depends on the details (cooltubes/heatshields vs bare bulb, carbon filters, stealth required etc) but generally I would think 2 or 3 smart fan II's would easily cover it quite stealthily. Or a decently amped fan like a delta for exhaust, and any quiet half decent fan to blow around inside the cab. In my opinion (and yours by the looks) all the emphasis should be placed on the fans doing the actual exhausting. The circulation fan is just blowing the heat around, kind of like a fan-forced oven. It is still very necessary to have that circulation going on of course, just that the exhaust/s are what is doing the real cooling.

If you want to elaborate more on what you're leaning towards, I'd be glad to help edit your choices, but right now anythings possible. If I had a true blank canvas for a nano grow sort of what you're thinking of, I think I would look at a 70w in a vertical cooltube, with 8 square pots around it, and possible some CFLs on top, also vertical. So You'd have the cooltube on it's own flow, no filter, and then you'd need another filtered exhaust system at the top to air the plants, and the CFLs if you use them.

Disfunky, I only approach it from my own perspective. I know that I've never seen an AC fan speed controller in a pc modding store, and the only AC control I use is a generic hydro-store fan speed dial, that plugs in inline easily. It has no specifications anywhere on the unit and I don't really like using it cos I know there must be some kind of formula involved to have the right controller for each seperate fan. On a 6" centrifugal, it baaaarely makes any difference to the noise/speed that anyone can notice. I really have to listen for it and it may even be doing nothing and it's a placebo effect? lol. Contrast that with a cheap hydro store 6" axial inline and it will slow it right down to nothing or perhaps close to nothing and it buzzes so bad it sounds like it will blow up or electrocute me. So basically it handles every fan differently and it seems like a crapshoot and not the way I like to go about things.

With a 12v pc fan there is almost endless fan speed controllers in modding stores, on ebay, or anywhere you can think of. They're all clearly specced as to how many watts they can handle per channel and they often have zingy little extras and basically look cool as fuck and do their job perfectly as they're meant to. The only downside is that when you need a controller for the higher amperage 12v fans, there is less choice. But then you can still fall back on an adjustable voltage power supply and adjust speed that way. Or as we discussed a few pages back, you can use a PC's PSU and get a whole range of voltages out of it very simply, with enough amps to run 10 cabs' fans.

That is all based on the assumption that you will want to quieten any of these fans down. Any of these multi-amp high power ones we discuss are very loud whether AC or DC, like noisy hair dryer and vacuum cleaner level. But once you slow em down, they'll be much quiter and still have more amps/power than a weaker fan which you didn't have to speed control.
 
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maryjohn

Active member
Veteran
Thnka scrub, great reading.

I remembered why I had to wash my carbon. In a runnermaid you have to move it every time you open it. So when I did that the dust would settle down on my heat shield. But of you have a proper cab it's no big deal.
 
as always Scrub you are a great help thanx for the info. iv got through a few pages and my questions that i asked earlier were pretty much answered. sorry for jumping straight to the end of the thread without takeing the time to read through. peace
 
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