If anyone is considering adding a CPU fan exhaust pipe, consider this roof-drainage "flexipipe" available at Lowes and Home Depot. funny what you can come up with when you have caught the SPC bug.

http://www.gutterworld.com/product.asp? ... =flexelbow

it will bend in any direction, and can be shortened/expanded like an accordian. the big end ('female' ?, lol) is big enough to strech over a small HS fan (about 70 mm square is viable). If you need to fit it around a 60 mm fan, wrap the fan first with some screen-door weather stipping for a good seal. if you cut the large end off, you could possibly stretch out the accordian over an 80 mm fan with a little work.

home depot also sells a matching 2 5/8" x 3 5/8" mounting bracket that the small ('female') end of the pipe slides over. the mounting bracket has 4 screw holes which will allow you to mount the pipe perpendicular to a case side, rear case venting, etc. the opening is about 2" x 3" which is approximately the cross sectional area of an 80 mm fan! (the circular blow chamber of the fan, not external dimensions).

an example application: the achilles heel of this nifty little HTPC case http://www.dansdata.com/images/atc620/backopen560.jpg is poor air circulation. but, it sports a rectangular vent section in the back! imagine the processor with a 'normal' square block HS and a 60 mm fan on top pointing upwards being vented out the back of the case with a simple 90 degree bend of the flexipipe. if i ever do this, I WILL post pictures

ghetto stylin' at it's best - your cost... $4!

Nice idea, unfortunately the ridges can cause air turbulence inside the tube, which can increase noise and temperatures. So it's better to use rigid pipe which is smooth inside, but of course it's difficult to find it shaped exactly right.

Just something to be aware of, but it would certainly be better than nothing at all!

I've used 4 inch flexible drier duct (aluminized plasic over wire spiral). It's a chore to get it right, but if you stretch it before you glue it in place you can have all kinds of contortions in it without too many folds. Plus, with a 4 inch diameter, the votrexes caused by fold turbulence may actually improve flow mid-channel (or not).