Quick, Cheap, and Not-So-Dirty 80 mm Fan Mod

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Interesting way to mount 80mm fans to heatsinks — Malaclypse the Younger

Many CPU coolers, at least those not for the P4, are considerably wider across the length of the fins than they are in the direction of the clip. The Thermaltake Volcano 6Cu/6Cu+ is one such example, measuring 60 x 80 mm. Both come with a 60 mm fan installed on an anodized aluminum plate that clips into the top of the heatsink.

While cooling is adequate to good, the fans in both models (but especially the 6Cu+) suffer from being far louder than an equivalent 80 mm fan.

One could get or make a fan adapter to attach an 80 mm fan to such a heatsink, but this raises the overall profile, pulls the center of gravity away from the motherboard (making it easier to break off a socket lug in transport) and forces airflow through an unnecessarily small area.

I have long had an 80 mm fan installed on a Volcano 6Cu, but I had it ghetto-rigged with paper clips. I recently purchased the Antec tri-lite fan (a must-have item in my opinion!) and decided that it would cast the most light around the case and look sweetest if it was installed on the CPU heatsink. However, this method should work equally well for any 80 mm fan.

What you need:

  • 4 plastic motherboard standoffs from an old AT case
  • 1 80 mm fan
  • 1 heatsink, at least 70 x 60mm (test system heatsink was 80 x 60 mm)
  • Two-part epoxy — quick-setting preferred; I used JB Kwik.

First, if the fan you intend to use has never seen action, you should tap the screw holes with self-tapping fan screws, then remove them again. This roughens them up and makes the motherboard standoffs hold on much more securely. If you’re recycling a case fan, you can most likely skip this step.

Next, insert a motherboard standoff into each screw hole, then loosely fit the heatsink in the center of the four standoffs, shaving or trimming the plastic if necessary. It’s easiest to do this upside down so that the heatsink’s weight helps keep things settled. You do not need to have the socket clip in place at this point.

Once you have everything loosely fitted, mix up a little two-part epoxy and attach the plastic standoffs to the outside of the heatsink. Try not to get it all over, but if you do, do not tear everything apart to clean up. There is plenty of time to chip away excess epoxy as it sets up.

Wait till the epoxy starts to set up, then gently pry the fan loose from the standoffs. I repeat GENTLY because the epoxy is still fairly weak at this point. With the fan out of the way, you can now use a pocketknife, keys, or just about anything else to pry loose epoxy that got in places it doesn’t belong.

The heatsink can now be re-mounted onto your motherboard, assuming you removed it in the first place and didn’t just pull out your whole motherboard (which might be simpler for bolt-through installations). Wait a few minutes more for the epoxy to set up more, then press the fan gently back onto the clips and wire everything up.

Test as you would any new heatsink/fan installation, and fire up your rig! The heat coming off the CPU will help the epoxy finish curing even faster.

Once the epoxy has fully cured (4 hours for JB Kwik, 24 for JB Weld), you don’t even have to be particularly gentle in removing and remounting the fan.

Those who wish a little extra structural security for LAN party boxes may wish to use thumbscrews and nuts, either plastic or metal, in place of the motherboard standoffs. Those who are particularly fanatic may wish to use a metal-bearing epoxy such as Arctic Alumina, along with brass screws, which should increase the heat-dissipating area of the heatsink slightly (though I doubt it is significant).

However, if your rig doesn’t get moved much and has a window, standoffs should work just fine. It shouldn’t be difficult to check if your fan has shaken loose in transport — in fact you might even choose to pull it off to lessen the strain on the CPU socket and reinstall it on the other end.

As for the original intent — mounting an Antec tri-lite fan on the CPU — I can only say that it was a smashing success! As sweet as this fan looked installed in the usual exhaust position, it looks much better seen face-on through the window.

It also works better than the fan it replaced, though it runs at considerably lower speed — about 2700 RPM rather than 3400 — and is quieter to boot. Just about any midrange 80 mm fan is bound to be quieter than the 60 mm you’ll be replacing.

All this does leave a small portion of the fan (10 mm on either side) hanging out past the last fin, but that doesn’t seem to be a problem. In my case it’s an added benefit, as much of this leakage blows right on the passive northbridge cooler.

Malaclypse the Younger

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