Hoot’s Pin-fin Waterblock

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Bill Adams DIY waterblock test

DIY: Hoot’s Pin-fin Waterblock

Hoot's WB

Hoot: When I set out to build a waterblock (sink), I looked for the following attributes:

  1. Inlet jets down onto the area directly above the die
  2. Lots of turbulence-inducing surface area
  3. Spiral channel to force the water to flow over as much area as possible before exiting
  4. Channel volume equal or greater than the volume of the ports (no pinch points)
  5. Baseplate and pins machined from one continuous piece of material (no additional thermal barriers)

The whole process is chronicled HERE.

You’ll have to jump through various parts in the six page thread to see pictures of the evolutionary process. I chose to use a baseplate from a pre-production heatsink made by Global Win, model CDK-38, which was profiled by Joe

Not needing all that pin height, I initially cut the pins down so that their tops just touched the bottom of the cover. That way, the water would not try to take the path of least resistance if a gap existed above the pins and below the bottom of the cover. I made my spiral guide from a strip of copper that simply sits down in the pins. It does not contribute to heat removal, just directs the water flow.

After some discussion, I decided to reduce the pin height in the outer ring of the channel, since most of the heat would have been removed from the copper by then and in hopes of reducing pressure drop. In that thread, I believe someone mentioned a company that forges pinned bases, so a baseplate similar to this one can be found.

Soldering the exterior wall to the base and the cover to the wall was not very difficult. Tin all mating edges first, then heat and let them settle upon one another. That reduces the amount of solder that flows onto the inner baseplate area, causing another thermal boundary.

Bill Adams: A very fine looking waterblock, lapped to perfection. My only criticism is that the outlet is a bit too close to the adjacent mobo mounting stud. In terms of performance this will be the DIY wb to beat; excellent execution Hoot. Dare I say it’s a “Hooter”?

Hoot CW

Hoot PD


Hoot’s waterblock is better than almost all commercially available
waterblocks, and its performance is not dependant on having a large pump (relatively speaking, it does better at low flows).

DIYers interested in testing their own waterblock can find out more HERE.

Bill Adams

John “Hoot” Hill


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