CPU cooling mod - Another air duct

Cheap soda bottle air duct

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This page is a step-by-step guide on how to make an ultra-cheap but effective air duct from an old soda bottle.
Normally, a CPU cooler just cycles warm air from inside the case though the CPU cooler's fins. A CPU air duct draws cooler air from outside the case directly onto the CPU cooler, making it more efficient.

Tools needed:
  • Hobby knife and scissors
  • Metal file
  • Heat gun or ordinary hair dryer
  • Dremel rotary tool (or similar) with cutting disc
  • Screw driver
Hardware needed:
  • One soda bottle (2-litre type made of thin plastic preferable)
  • Old 80mm fan (doesn't matter if it is defective)
  • An extra 80mm fan grill just for looks
  • 4mm machine screws and nuts

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Buy a 2-litre soda, drink it, and wash the bottle.

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Measure the distance between the top of your CPU cooler and the case cover. Then cut out a section of the bottle matching that distance plus 20 millimetres.

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Place an old fan with the same size as your CPU fan in one end.

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Using a hair dryer, warm up the plastic around the fan untill it shrinks in around the fan. The picture above shows what you should be aiming for. You can practice on the other bottle pieces first.

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After giving the corners a sharp fold, the fan end of the duct should look like this.

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Now we need to mark and cut a hole in the case cover so the duct can draw air from outside the case.

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Place the Dremel cuts like this. When the section is cut out, clean up the edges with the metal file.

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Mount the duct on the fan. It should stay on by itself. If not, heat-shrink it some more.

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Check the clearance while you put on the case cover, the duct should not put pressure on the heat sink. Trim it a little if necessary. You can put on a fan grill if you want to style it a bit.