making a duct. 3ft down to like 3 inches.

ok, once i start folding, i plan to get my comp up from 1.0Vcore and get this 1700 moving at some speed. But, with my volcano 9, its got a great fan on top, but until i get watercooling im gonnat ry to get some seriouse perforance with what i have. So, I was thinking of trying to duct a box fan right into the heatsink, and becuase box fans dont have very much static pressure, or can have backflow occur very easily, i plan to have 2-3 box fans, just one behind the other. So now the only problem is, how do i make this duct? what would i use and how would i make it? I was thinking of ductaping some cardboard together, but i dont know if i even have enough.

What do you think?

-f1

Can this span an entire wall of your room?

Because in order to go from 3 feet to 3 inches without completely choking the box fans your duct will have to use a very slight angle of slope.

If you want some extreme aircooling... A centrifugal blower can be had for around $40 bucks and they can create more pressure and comparable airflow to what you are considering.

There is a rusty old industrial Squirrel cage out by this air conditioning repair company near here... but I figured it was just sitting out because the motor burnt up. I don't even see power hookups (Oh yeah, the freaking thing is BELT DRIVEN (motor turns belt which turns fan).

I'll bet that would put some crazy air out (It looks like the cage itself is about 1-1.5ft diameter)

ok Thanks guys. IMOG, you do have a point, the walls of the duct will have to have a very shallow slope hmmm. im just trying to figure out something that wont really cost me anything but will get me the best performance.what about a black trash bag? it wouldnt have to cut down any, id just tape the open end to the fan, and the other ill cut a hole and tape to the heatsink. I wonder if that will work. Will it give me an advantage over a smt fan 2 at full blast?

TIA
-f1

I don't think this is going to be feasible. I don't think the trash bag thing is worth trying, but try it if you want.

Hehe, a trash bag....I remember when i made a duct from the ac vent in my roof to my radiator. The temps went down about 10c when the ac was on...but when it turned off...It just wasnt permanent. But trash bag is good.

i dunno what that fan box thing is, but heres what i did...hope it helps u out

1) Find an old crappy fan that doesnt push enough air, or even better, a broken one!

2) Cut out the plastic things holding the actual fan blades/bearings in, usually four little "rails", u can usually cut em out with a good pair of wire cutters (a new addition to my moding arsenal) and u should be left with a fan casing

3) For better results, u can also sand down the jagged edges and make it more aerodynamic, which is what i did, i highly recommend this

4) Now cut the hole out above the hsf (remember measure twice, cut once), get a fan that blows air in a cone-type pattern (around 30-40 cfm), screw the fan casing u just cut and sanded onto the fan that your gonna duct, or tape it onto the fan and screw the mini duct onto the case side panel

5) Your cpu temps will now go down as much as 5C (mine did)
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latin girl Cam

dalilman52 said:

i dunno what that fan box thing is, but heres what i did...hope it helps u out

1) Find an old crappy fan that doesnt push enough air, or even better, a broken one!

2) Cut out the plastic things holding the actual fan blades/bearings in, usually four little "rails", u can usually cut em out with a good pair of wire cutters (a new addition to my moding arsenal) and u should be left with a fan casing

3) For better results, u can also sand down the jagged edges and make it more aerodynamic, which is what i did, i highly recommend this

4) Now cut the hole out above the hsf (remember measure twice, cut once), get a fan that blows air in a cone-type pattern (around 30-40 cfm), screw the fan casing u just cut and sanded onto the fan that your gonna duct, or tape it onto the fan and screw the mini duct onto the case side panel

5) Your cpu temps will now go down as much as 5C (mine did)

Click to expand...

I'm not quite sure what this means.

I can tell you this, placing one box fan behind the other will not increase your airflow. Air will only flow as fast as the front fan (the one nearest the cpu) can push it. This is because the fan nearest the cpu will actually restrict the flow of the fans behind it if the rearward fans are turning faster. If you could gauge which fan moves the most air, the the second most, then the third, it might help some, but you have to understand that the blades of the first fan in line will restrict the flow of the fans behind it.

If you try the trashbag idea, look for a fan with steel blades. A fan with plastic blades will be much more suseptible to fin flattening and blow-by caused by the increased resistance to airflow.

An alternative to your box fan idea may be to find a squirrel cage fan as mentioned earlier. A trip to the local junk yard could provide you with a nice 12 volt DC squirrel cage blower from an automobile heater. Airflow should be great and duct building should be easy. I'm not sure how much power it would take, but an old battery charger should power it nicely...any flea markets where you live?

Cuda said:

I can tell you this, placing one box fan behind the other will not increase your airflow. Air will only flow as fast as the front fan (the one nearest the cpu) can push it. This is because the fan nearest the cpu will actually restrict the flow of the fans behind it if the rearward fans are turning faster. If you could gauge which fan moves the most air, the the second most, then the third, it might help some, but you have to understand that the blades of the first fan in line will restrict the flow of the fans behind it.

If you try the trashbag idea, look for a fan with steel blades. A fan with plastic blades will be much more suseptible to fin flattening and blow-by caused by the increased resistance to airflow.

An alternative to your box fan idea may be to find a squirrel cage fan as mentioned earlier. A trip to the local junk yard could provide you with a nice 12 volt DC squirrel cage blower from an automobile heater. Airflow should be great and duct building should be easy. I'm not sure how much power it would take, but an old battery charger should power it nicely...any flea markets where you live?

Click to expand...

It wouldn't increas the max airflow, but would it increase the static pressure?

squeakygeek said:

I'm not quite sure what this means.

Click to expand...

It took me awhile to figure it out, but I think he means to cut up an old case fan leaving only the outer case of the fan then attaching it to the existing cpu fan as a duct. If I'm not mistaken, the next step is to cut a hole in the side of the case over the cpu fan and mount another fan there, blowing air onto the existing cpu fan through the new extended duct. I think

squeakygeek said:

It wouldn't increas the max airflow, but would it increase the static pressure?

Click to expand...

It might, but if the fan blades flatten out too much because of the static pressure, you're fighting a loosing battle.

But the question is, would it be better than what he has now? It very well could be.

I used an old pipe from a tumble dryer, this worked nicely and cooled things down, i ran it into the cellar beneath the house where the air is cool, works well

1) Modena's box fan idea wasn't supposed to increase airflow - it was meant to improve upon the pressure a single box fan creates. His idea would do that.

2) Go hold a garbage bag out in the wind - it's got an annoying noise to it. I would still like to see this attempted, for laughs if nothing else.

3) If you want to cut out the fan hub from an old fan and use it as a duct as suggested, that's a good idea. However you should place the hubless fan between the heatsink and your good fan so it counters the deadspot of your good fan. Having two fans of equal airflow in series will not provide much benefit, especially not with such a short duct - it will probably be worse.

4) Lennytiger: YGPM
VVVVVVVVVVVVVVVV

nooooooonnonononononooo! imnot going to cut up my preciouse smt fan 2!

anyways, yes this idea was to create more static pressure and im sure a boxfan move more than 150CFM of air, just has terrible static pressure. And also, this was just as a temporary now that I am folding again and wish to bump my CPU back up to 2.5Ghz making 120 thermal watts. Just a temporary until i get chilled watercooling.

Some time i might try this, but the only problem is that it will make so much noise my mom wont want it on, meaning it wont be folding maybe if i move it up to my room

anyways, what were you talking about by,"If you try the trashbag idea, look for a fan with steel blades. A fan with plastic blades will be much more suseptible to fin flattening and blow-by caused by the increased resistance to airflow.If you try the trashbag idea, look for a fan with steel blades. A fan with plastic blades will be much more suseptible to fin flattening and blow-by caused by the increased resistance to airflow."

anWHOA! I gotta go! ill be back sometime hopefully

EDIT: ok im back.


anyways, that automotive blower is a great idea! that has ALOT of static pressure. couldnt my psu power it?
well probly not. but i could get an ac adapter for it and have it come on when i turn the power strip on. what does this thing look like or how big is it? how much would i spend at a junkyard for it?

yea, that IS what i mean, using the old fan casing of an old fan and attaching it to another fan, i cut the hole directly over my hsf and it lowered my temps like 3c, a pretty good improvement, although my case has like a lot of positive pressure, sfII blowing in 75 cfm, and sf I blowing in 53 cfm on full blast, theres not much going out, o well... i only have psu exhaust (barely any) and a .26A fan which i have n o idea how much it blows, prolly around 30-35 cfm
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PUBLIC FLASHING

ok update.

i didnt have too much luck because the bags arent big enough to fit over the fan, i tried it at first and i got the same temps as my smt fan 2 on low, but thats becuase the bag couldnt cover the whole fan, especially the part that blew the most air. and to get the nescisary static pressure, i will need to use 2 or maybe 3 of them.how much cfm do you think id be moving? More than 75?

Yeah, ... the car heater/AC blower is a great idea.
I have a whole slew of extra GTO parts in the shed. There
has to be an old blower motor assembly in there somewhere.

well i just need to get some more boxfans, when im all done with this whole thing ill post back, in the mean time, i think i should get one of these to move the air through my volcano 9

Click here!