The Nebulous Cube

Building an external watercooling system – Dino Velez (“Thundr7”) and Kevin Heckeler (“Pinky”)


Earlier this year, we developed an external radiator box for Dino’s CPU watercooling system. To our mutual surprise, this outperformed anything we could have bought for nearly 50% more cost of construction.

The object of building this unit was to house the cumbersome watercooling setup externally while retaining some of the visual aesthetics of Dino’s computer. While developing the plan, we realized that, if done correctly, we could create a ‘wind tunnel’ effect through the box, increasing the effectiveness of the pull of air through the radiator.

Without further delay, here’s the Nebulous Cube:


  • Waterblock – Maxxxpert MXL Miro Spiral – purchased new from Kevin – $40
  • Pump – Enheim Pump 1048 – purchased online from Cool Technica – $68
  • Heater Core (for Chevy) and Automotive Door Edge Molding – purchased from Advanced Auto – $41
  • Plastic Filing Cabinet (used for box) – purchased at Staples – $9
  • Fittings, Clamps, Tubing, JB Weld – purchased at Home Depot- $18
  • Fan (150mm AC Fan) – pulled from junked movie projector – Free 🙂
  • Power Switch (double pull/throw) – pulled from junked washer machine – Free 🙂
  • Reservoir (Hellman’s Quart Size Jar) – Price Chopper – Free after consumption 🙂
  • Power Light and Grill Material – pulled from spare appliance, be creative – Free 🙂
  • Caffeine (Spanish Espresso) – Price Chopper – $1.50 /lb.

Total Cost: $177.50 (plus distilled water, optional)


Make the coffee, the stronger the better… this takes some patience and steady hands. On second thought, save the coffee for later.

The order may not necessarily matter, for sake of ease we will list the steps in the order they were done. Results will vary.

1 – Depending on your luck and selection of heater core, you may or may not have to add barbs (or some type of connectors for the tubing to attach to the radiator). Dino had to purchase barbs, and none of the ones available at Home Depot would fit perfectly, so he bought some JB Weld (Liquid Steel) to attach the barbs to the heater core. JB Weld required 24 hours to set.

2 – Measure the diameter of the front hole to be created (suggest you mount the radiator in front). Be sure to only allow for enough air to pass through and not around the radiator. The radiator should sit flat on the bottom of the file cabinet when measuring and marking. Cut the front portion of the cabinet.

3 – Add door molding around the edge of the hole you just cut to seal any gaps between the heater core and your cabinet. You will need to brace the bottom portion of the heater core to push flush against the front of the cabinet (see photos below). Dino used a spare plastic drive bay cover and sank a few screws through the bottom. Use whatever long screws you have available to pull the top portion of the heater core flush against the front of the cabinet. Your radiator is now mounted.



Dino Velez (“Thundr7”)

4 – Now to the back of the unit. Measure the diameter of your fan (suggest finding one than runs on AC current) and cut out the hole. Mounting your fan will have to be your responsibility, we cannot possible cover every type of fan you’ll find in the trash. Be creative.

NOTE: The better the fan, the better your cooling. Remember, part of the benefit of watercooling is the decrease in noise required to cool your CPU and other heat generating components. Adding a large, loud fan defeats some of the purpose of having this setup. Be reasonable, a little noise is expected, but nothing that should annoy you.


5 – That was the hardest this gets. Now you need to secure the reservoir, pump and attach your lines. The power switch and power light are optional and recommended, but certainly not required for this to work. Again, be as creative as you like – after all, this is your mod.

6 – Final touches and installation of the waterblock will also vary based on your specific setup and components.



The results are impressive and far exceeded our expectations. It seems several things were at play here that made this work.

The first was the pulling action across the fins of the radiator, which is dynamically more effective than pushing air across the surface. The fact the cabinet had a lid that sealed well when closed (and the pull pressure of the fan helped to fortify that seal) benefitted this design.

The third item was the actual fin design of the heater core (the water runs through the individual fins of the core) versus what is sold on the watercooling market, which are copper tubes soldered to thin aluminum fins. Soldered joints and conduction of heat through those joints tend to reduce their efficiency. In this case, the warmed return water from the core has less metal between it and cooler air being pulled across the fins, creating a faster heat exchange and cooling effect.

Dino has since upgraded his CPU, but at the time of the build and these photos he was running an AROIA Y 0213 XP1600+ (Palomino) at 1.9v and 1.92 GHz stable. Room temps were 21 C at the time of testing, CPU core temp (internal diode) was 22 C.

Yes, you read right.

We verified this was NOT a fluke, bios issue, or diode problem (especially since we have tested many other CPUs in the past few months and have seen insanely cool temps with those as well). Currently, Dino has an AIUGA 0247 XP1800+ (Tbred) at 1.95v and 2.1 GHz stable. He has moved this unit to the living room window to enjoy the fresh winter’s air, so today’s results are a little skewed. Right now it’s about 5C outside, about 22C inside the room, and the CPU’s internal diode is reading 32C.

Dino Velez (“Thundr7”)

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