Mounting fan half in half out of case?

[kzochert]

I have heard that this is optimum for proper cooling, because it doesn't allow the air to go back into the case. But I don't know how I would be able to do this.

Any suggestions?

Thanks,

 

[ThisIsMatt]

Huh? I can only think of one thing that you might be thinking that would be optimal, and that's the have an air duct going straight to your cpu fan, so that the air being blown on the hs is straight from the outside of the case, rather than the air that's already inside the case...

 

[kzochert]

Maybe I should rephrase this, Instead of entirely mounting the fan inside or outside of the case, you mount it in the center. So half of the fan is on the inside and half is on the outside.

I just need to find a way to securely do this.

 

[ChefJoe]

why not just attach to the inside like everyone else, use simple fan screws, and put a bit of weatherstrip or some sort of gap filler around the hole on the inside. As long as it doesn't stick back into the fan blades, it'll be perfect and seamless.

 

[ThisIsMatt]

<< Maybe I should rephrase this, Instead of entirely mounting the fan inside or outside of the case, you mount it in the center. So half of the fan is on the inside and half is on the outside.

I just need to find a way to securely do this. >>

That crossed my mind the first time, but then I thought to myself, "Self, that makes no freaking sense", and I dismissed the idea. If you hold a can of soda from the top rim, the middle, or the bottom rim, you're still holding the soda in virtually the same way, right? Same with the fan, except your case is gonna look sofa king we tall did with fans sticking halfway out...

 

[kzochert]

It sounds reasonable, but the whole soda can analogy doesn't work too well. The can isn't moving air.

I will just mount them on th inside, and add duct tape to cut back on any air that wants to go back inside.

 

[jcmkk]

Duct tape? You might as well just mount them half in, half out it would look just as ghetto. Your theories aren't making any sense. Why would you use duct tape? To seal the fan in case? Your case is never gonna be sealed. Most likely you have little vent holes in the side of your case anyway.

 

[Mday]

if you examine any can, you will notice that its kinda gonna be very hard to do... unless you make very price measurements...

just mount the fan FLUSH to one side, and wrap something at that "joint" to prevent airflow...

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mounting the fan half out of the case is kinda a stupid idea. it has been 3-4 years since i made my first mod. i have seen ideas come and go. and this idea is one of the more stupid ones meaning, there is a simpler solution.

when i did my first blowhole, waaaaaaaaay back when... i made my hole smaller than the actual fan, this is intake, so it does not really hurt... anyway... i lined that hole (on the side where the fan would touch) with a sticky-back weather foam... much like what you stick to your whatever to install and seal an airconditioner. this acted both as an air tight seal, and as a vibration dampening mechanism. just watch how tight you mount your fan.

dont forget to use air filtration to reduce dust in your pc... of course i have heard of the dryer sheets... the pantyhose.. and of course my own... window screening =)... if you have an all Al case, the AL screening is perfect for making a custom filter... if you have black, the fiberglass (covered in some black "rubber" dealie) will match that...

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real men do not use duct tape... we use foil tape. "fuct" tape dries out.

 

[Becks2k]

actually i think theoretically a fan pushes the most air if mounted 1/2 in 1/2 out

 

[FenrisUlf]

Mounting the fan inside, outside, or half-in half-out will make no perceptable difference. What is important is how the air enters and exits the fan. The most efficient shape for air to enter a fan is with a bell-shaped inlet like those on wind tunnels. Since very few people want to put a two foot intake on their case fan just to get a few percent increase in airflow, this isn't a common soloution. Air doesn't like to make sudden changes in direction or to have sudden expansions or contractions of space. When a fan blows into or out of a case, the air is suddenly going from a small cross-sectional area (the fan) to a large one (the case or room). This is not ideal for fan effiency. Fan makers try to help a (very) little by sloping the edges of the fan case out, but this probably has a negligable effect in real applications. If you were really serious about eeking out every last percent of effiency from your fan, you would put a cone on the front and back hubs (like you see on propeller aircraft), and ductwork to slowly change the cross-sectional area of the airflow, but again, with these size fans it's just not worth it.

Where you can really make a difference is by having a hole the same size as the fan (so there's no restriction or sudden change in diameter. Seal the gap between the fan and case. This keeps the airflow in a coherent direction into or out of the case without any "leakage". Mounting the fan half-in half-out would minimize air leakage, but the (maybe) .5% difference is just not worth the extra effort to cut, seal, and securely mount the fan. When I put in a fan, I usually cut a round hole and mount the fan with screws, using a washer as a spacer between the fan and case. I then put a bead of silicone between the fan and case, smoothing it along the inside of the fan with my finger. After it dries you can remove the screws. This helps keep the airflow smooth and insulates the case from the vibrations of the fan.