One of the best ways to keep your system running cooler all around is to install a "blow hole." A true blow hole is a fan installed in an opening in the top of a PC case (like the blow hole of a whale or dolphin). But the term has also taken on a much more generic meaning that includes any fan opening cut into a case, side, top, front, or back. Here's how to install a blow hole as easily as possible without destroying your case.


The first step is to figure out where you need to install a blow hole. The top is always a good start since hot air rises. A blow hole set to exhaust air from the top of the case will stop heat from building up. You can also install a blow hole is in the side case panel. A blow hole in the side case panel can be set to blow air on the video card area or the CPU. These are the most common areas to install blow holes, but you can install one anywhere you feel the need for cooling. Make sure you check your case for clearance before removing all electronic parts including the power supply to keep them from being damaged by metal shaving.

Installing a 80mm blow hole in the top of our case. Start by checking for clearance on the inside of the case. The power supply and CD-ROM drive are both very close to the top of the case so make sure you have a clear area in between them. Once you find the general area that you want to use, measure from side to side with a ruler to center the blow hole. If the total width of your case is 8" and the center would be at 4".

After you have marked the center of your case and made the cutout circle it is a best to use a punch or an awl to make an indentation in the sheet metal, this helps keep the drill bit from 'sliding' when it's time to drill. If you don't have an awl you can use a screw or nail to make the indentation instead.


Once you have marked the center of your blow hole you can start to draw the outer circle of the cutout. A drafters compass works best for this job. . Even a inexpensive compass that you can buy at your local drug store will work. Use a ruler to accurately set the compass to half the diameter, this is the radius, of the circle you are going to cut. With a 80mm fan set the compass to 40mm. Then we placed the tip of the compass in the indentation and carefully traced our circle.

With the circle in place we start to drill. We start off with a small drill bit to keep the drill from 'walking' or sliding. Then we use a larger drill bit the enlarge the hole. Once the hole is large enough for the blade of a jigsaw (about 3/8") you can start cutting. First apply masking tape to the area outside of your cut to protect the finish of the case. Also apply the tape to the bottom of the jigsaw's metal foot, don't leave the tape out all together or you will probably end up with scratches all over your case.


To cut the blow hole use a jigsaw. If you don't have a jigsaw you can use a Dremel Moto tool instead. If you use a Dremel tool make sure you use the reinforced cutoff wheels not the regular kind. The idea is to cut out the area inside the circle and leave the rest intact. When you are finished cutting you should have a somewhat rough hole. Use a Dremel with a grinding wheel to get most of the rough edges off. Then use wet/dry sandpaper to finish the edge until it was smooth. If you don't have a Dremel you can do without.

Once the smoothed out blow hole is almost finished, use a 80mm fan grill as a template to mark the corner holes for the fan. Then drill the hole out to 1/4" so that you can use grommets in the four holes. Once the holes are drilled, squeeze rubber grommets into each hole and mount the 80mm fan and fan grill in place using long fan screws. The fan is set to exhaust air from the case though the blow hole.

The finished blow hole not only helps keep our system cool, but it looks very high tech too. We all know that performance is nothing without style, but with a blowhole you can have both.

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by FastEddie