Guide Blowhole Templates

This could be usefull for some of you modders,

Save it and print it out at full size

 

I prefer the non circular ones.
Those will restrict airflow and make more noise. : \

 

restrict airflow and increase noise? You on crack?

The only reason that fans are square is for mounting them. The area that air flows through is circular, so how would a circular hole that is the same size restrict airflow?

 

Take a fan, and remove the blades, look through it. What you see is not a circular hole, but a 'wasp waist' shaped hole. This improves airflow and reduces noise in comparison to a circlar hole.

If you're going to start getting abusive, at least know what you're talking about first.

 

I don't mean to hijack the thread or anything but there is "wasp waist" shaped one's over at moddin.net in the download section

 

am i the only person here who dremmeled out the middle of an old fan and used it as a template? just chop out the middle, and you have a good strong template, you can even screw it onto whatever you are cutting if you dont want to draw on it....

just a thought.

 

erm, my apologies, it wasn't supposed to sound offensive. In fact, it wasn't even aimed at you, so I don't know why your getting arsy.... hmm, odd.

Anyway, I've never noticed that the hole is anything other than round. I guess I'll have a look when I get home. The difference has got to be negligible though...

 

I'm getting "arsy", as you put it, because I am a moderator and this is one of my forums.

The difference is noticable, and if you're going to do a job, you might as well do it right. Most even find the wasp waist design easier to dremel out.

 

I used a hole saw to drill my holes for my 120mm fans. Yes tey were wasp waist design. However, looking at the shape of the hole compaired to the fan, not only does a circular cut look better, it only blocks maybe an 8x8mm area around the edges. The fan blades themselves are not blocked from view, but the side discharge air may bounce around and get caught in the corners. How much CFM is lost by it? I would say 1-2 CFM. No big noodle cooker. For 80mm fans it would be even a smaller blocked area. Heck, most fan grills are circular, and have a thick outer edge, blocking the "wasp waist" design out better. Okay, I have seen some of the dremeled attempts at blowholes, and by golly, they are ugly, more like ovals than circles. The wasp waist design would certainly be easier to dremel out. If you make a mistake, it isn't as easy to see on a wasp waist design. If a circle isnt perfect, you can tell. However, for pure asthetics, a circle would look better. I, personally, will never drill a blowhole with a dremel. Hole saws get the job done much more efficiently, and its a perfect circle. So, whatever cooks your noodle gets the job here, no use arguing unless you really want to squeeze every last ounce of air out of your fan.

Conclusion:

When to use circular cuts:
- If you are using an already circular fan grill
- If you have a hole saw handy
- If you are cutting through thick material (such as 3/8 thick acrylic) and need to use a hole saw

When to use wasp waiste cuts:
- If you want the least noise possible with the most performance (maybe if you have a quiet case and have quiet fans that need the most performance they can get)
- If you are dremeling (sp?) through thin material
- If you are using a wire fan grill

There, they are both best for their own things. One is not better than the other, they are simply used for different applications. Everyone happy? Good.

 

The whole fan thing is there because then you can also get the holes right and stuff, I didn't want this to turn into some kind of flame war, I just wanted this to be some kind of help to some people

 

I feel bad for you Mosha.

Ahh well, let people do what they do. Thanks for the templates! I probably should use them for hole placement.

 

Just coz I've got 2 brothers and I love stiring things up a bit
Wouldn't the best plan to improve airflow be to cut away as much metal as possible, only leaving enough to mount the fan? Then the only restriction would be the fan's body it's self...

 

Yeah but who wants to see the body of the fan? Maybe if it was either interesting or invisible... although I'll admit my plan would be something to that extent if I end up with a 2x120mm radiator so I shouldn't be talking.

But yes, you're quite right.

 

hmm, I think I agree with danmagicman7...

If you've got a "wasps arse" shaped hole, and a normal fan grill, how odd is that going to look! I can't imagine that the effect on noise and cfm's is any more than miniscule (sp?).

Anyway, thanks alot for the templates Mosha I'll be sure to use them when my new case arrives.

 

Yeah, thanks for the tip Mosha. But you have inspired me to rethink the time honored fan mounting method. Let you know if I come up with anything usefull.

Cheers

 

Umm is it just me or are they the wrong size. I printed it out and the 120 mm fan is like 144mm??

 

Save image as> Open word> Insert picture and well it should work...

 

Mosha, your help is really apreciated, I'm going to do some blowholes and when I saw this I came in inmediately.
What I just pointed is that I just wouldn't use that design since I'm a silence and airflow freak.

I've done the test with a 120mm fan, my gf was with me, and we both noticed that when I used a circular blowhole the fan didn't have as much airflow and that it was really louder.
Try it, if you want, just cover those parts with tape or with your fingers, you'll notice what I've said.

 

Its over, we have accepted that the circular cut hole is inferior to the wasp waist design. Happy? No reason to keep on trying to say your right, we believe you already, look at my previous post.

 

Uhm, excuse me for being a dumbass, but what exactly is the 'wasp waist' thing? And how am I supossed to cut out holes for my fans if you guys are all saying that the templates he posted up aren't very effective?