Custom fabrication of an air duct hose

10/16/2004 10:14PM by Phaysis

To help keep your CPU cooler, you could pay a lot for a snazzy LED backlit CPU fan with 900 copper fins, a peltier device, and cold-cathode neon ropes, or you can fly your ghetto flag and build your own air duct! That's right, build your own air duct! Build your own? People still do that, y'know.

The goal is to duct cool air from outside the case directly to the CPU fan and heatsink assembly. Fabricate the duct, determine where the duct will run from the CPU fan to the side panel, then later drill or cut a hole through the panel. Attach the duct to the fan, then to the panel. At the current time, I haven't drilled the hole on the side yet, but everything else is good to go.


So, to begin with the duct fabrication. Build a cardboard tube the size you need (just big enough to fit over the venturi of the CPU fan itself). Around this form, wrap a few layers of cling wrap. You may wish to dust each layer with spray adhesive. After a few layers are laid, starting from one end of the form and going to the other, coil some thin steel wire around the length of the form spacing each turn evenly. A 3/4" spacing is optimal given the size of my duct which is roughly 3 3/8" across. Coat the form/wrap/wire with spray adhesive, and wrap a few more layers of cling wrap. To release the new duct from the form, pull the form's seam (where it is taped to itself) inwards to the center of the form; doing this along the length of the duct and form should release the duct. Fabricate, with more wire, some ends to attach to the duct so you could attach it to the case and the fan. Enjoy!

Detail images

Gather together a roll of plastic "cling" wrap, spray adhesive, and a small amount of thin steel wire. The wire gives rigidity to the tube of wrap, much like a dryer vent hose.

The cardboard form, cut to length and to the right circumference. Mine is slightly larger than the exterior of the CPU fan. The final fit is a bit loose, but it affords me the ability to easily lash it to the fan or take it off.

I placed tick marks along the form at 3/4" intervals on two sides of the form. This is a guide to me when I wrap the wire around the form.

At bottom, the old duct I made first as a proof-of-concept. In the middle, the cardboard form. At the top, the new duct made in the exact same way as the old duct except that the spray adhesive was used in the process. So far, it appears to be holding up better than the original.

And, finally, the finished duct in various states of flexing.