How To H2Ocool Your Power Supply

Uses oil – Charles Gilliatt

In this article we tackle an often overlooked item when water-cooling a system – the power supply unit.

I know what you are saying already “Just slap a block on the built in heat sinks and be done with it”. Well it isn’t quite that simple. Many heatsinks inside a power supply are live, and as we all know electricity and water are a bad combination. Now the second issue that most people bring up “Well, what if I purchase a power supply with isolated heatsinks or modify one that is live with ceramic pads to isolate it.”

Well that wouldn’t work all that well, even if your heatsinks had a flat area to mount a block to, or even if you custom made a block and mounted the mosfits to it. Most people forget that the entire power supply gets hot and the entire unit requires cooling, not just the heatsinks.

So here’s what you can do over a weekend and make all your buddies stare in awe. First you will need some basic supplies:

You will need a high quality acrylic adhesive, the cheapest block you can find, a generic fan is optional and is fun for the “bling bling effect”, the guts of a power supply (in this case an Enermax EG465P-VE 431W unit), a good metal ruler, a good plexiglass cutter. Items not shown include a builder’s square – trust me this is GREAT when cutting plexi and a sheet of 1/8″ thick plexi.

A word of caution: When dealing with the power supply unit, be very careful when extracting the unit as they do hold a charge well after they are unplugged – hook up a fan to the power supply and turn the power supply on while unplugged to discharge the capacitors.

This article is for information purposes only – neither the author or Overclockers.com will be responsible for direct or consequential damages if you modify a power supply as descibed herein.

Before tearing my computer apart, the Enermax power supply was tested and run with ~125 watt load measured by a Seasonic Power Monitor. The Exhaust temperature was read 1″ from the grill at 32ºC.

Now let’s begin: The first thing you will need to do is take measurements of your case to see how big you need to make the box – in this article I will be placing the PSU in two of the 5 ¼” bays on my Lian Li PC-V2000 case. As always, measure four times and try to only have to cut once. Remember to make sure that the block clears any part of the powersupply, you will see what I am talking about later, and also take into account the thickness of the plexi.

For those of you that haven’t dealt with cutting plexi, here are a few tips: First DO NOT take off the protective paper, in my case it is brown but it also comes in clear and a slight green tint, from your plexi until the project is DONE. This will prevent scratching of the plexi as you are working with it.

Next when laying out your measurements, remember to account for the thickness of the plexi when making your final measurements for the box. When using your builder’s square, score the plexi several times, however many times it takes to get about 35-50% through the plexi.

Then rotate the plexi so the scored edge is right at the edge of your work surface – I like to use clamps on the edges. My preferred technique to snap the plexi is to give it a good quick hit with the palm of my hand near the score joint. When cutting larger pieces I would suggest using a straight edge across the joint, applying equal pressure on either end while pressing down.
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If all goes well this is what you get:

If you don’t get good results, keep trying; I have perfected my technique through five years of art school (at least I learned something). Now repeat the process over and over until you get all the pieces required:

Now take a moment to remove about ¼” of the protective covering from all edges that require gluing and use a bit of sand paper to rough up JUST the 1/8″ of plexi that will receive glue:

Now apply the acrylic cement per the manufacturer’s instructions, using whatever is handy build the box; after you’re done, you should have something like this:

This would be a good time to do a quick test fit as well. If it doesn’t quite fit sand it down some and try again.

OK – now to fit the PSU into the box. I used some little plexi scraps to create feet for the power supply to glue it to the bottom of the box; if the PSU isn’t fixed to the bottom, it tends to move around and we don’t want that.

Then just glue the feet into the box; at this point you can also glue in the fan of your choice and simply wire it into the onboard fan leads – an 80 mm works the best – this isn’t required but can add a bling factor. At this point I would also attach an extra bit of wire to the ground terminal of the PSU, usually a short length of green wire that was connected to the shell of the PSU. Once the PSU is installed in your computer, just attach it to bare metal in your case – this is what you should have at this point:

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Now we turn our attention to the lid.

Notice that in the above image I have added some blocks to stop the lid from sinking into the box – depending on the method you choose, these blocks may not be required.

First we need to drill two holes to mount the water block to the underside of the lid, allowing the two hose barbs to stick through. Again measure four times and drill once. When drilling plexi, make sure you are far from the edges and are using a good sharp bit:

Now that your block will slip up through the two holes, remove the protective backing from the inside of the lid and glue the top of the block to the underside of the lid; this is really just added safety, as the hose clamps are more than strong enough to hold the block in place.

Notice the notch in the corner – that is to allow the power leads out of the box. Now the fun part and the “secret” to this method:

That’s right – lots and lots of baby oil. I would suggest spreading around the “love” a little and purchasing a bottle at a time from several stores. You can’t imagine the strange look the clerk gave me when I went to buy 5 bottles at once – buy one get one free AND a 50 cent off coupon was my excuse, although I don’t think that helped put the clerk’s mind at ease.

The concept is fairly simple – the mineral oil (baby oil) acts as the non-conductive medium between all the hot components of the PSU and the block on the water cooling loop.

The table above illustrates that while mineral oil is not as good a conductor of heat as water, it is still vastly better than air. When used in combination with a copper block and a water loop, the heat will be quickly removed from the bath of mineral oil.

Before filling the box I would suggest giving it a good cleaning with some compressed air and even a little vacuuming to get any dust and loose bits out. Then remove all the protective covering from the inside and fill with the oil:

Once filled, pop the top on, slip it into your case, add into your H2O loop and enjoy. From the front, all your friends will think that your PSU is submerged in water. If all goes well, you should have something like this:

A powersupply that appears to be submerged in water. And the “bling-bling” of the blue LED fan just adds to the Lian Li’s blue power LED. On a side note, once the fan is submerdged it is totally silent – no churning, no nothing. The power supply under the same 125 watt load heats the mineral oil to a max of 49.1ºC – this temperature is taken 2 cm from the heatsinks on the powersupply.

I have run this PSU in my main system for close to one month now and have no problems what so ever.

Charles Gilliatt