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Part 1: The Mobile Heat Exchanger

I got this idea for water-cooling my PC in the summer of 2002.
At first I figured I'd just buy all the components I needed, install it and that would be it.
But then I got the idea of doing it myself and 'low-cost'.
Little did I know that I just started the most intricate and expensive water-cooling project to date.

I'm an avid reader of and in particular the Gathering of Tweakers forum.
This forum is visited by dozens of nerds and other ingenious people with loads of good ideas and projects
(usually hidden between a vast array of non-sense questions and remarks).

There was this one guy, Imhotep, that could make a near perfect copy of one of the best waterjackets around, the Maze 3.
It took a while before they were made and shipped, but when I got one and saw the amazing shine of this piece of art with my own
eyes, I got cracking at the rest of the setup.

I also needed a radiator and I was told that you could find good copper radiators really cheap at junkyards.
It needed to be full copper to reduce electrolyses and increase heat transfer.
I got a list of cars that had copper rads, but none of the yards had any nor did they have rads lying around.
I did find one, but it was too dirty, too expensive and too banged up.
Just when I was about to simply buy a Black Ice Extreme, my neighbour pointed out a garage quite close to where I live.
I knew about this garage, called Autotemp, but the dots never connected that they might be able to help me with a rad.
Maybe this doesn't seem very stupid to you, but I have to tell you that that specific garage is an A/C and radiator specialist.

DOH!! R-A-D-I-A-T-O-R !

So I went there to talk to them, explain what I was trying to do
and they just gave me an almost new, big, copper radiator for free!
The size was absolutely perfect, I could place four 80mm standard
PC fans in a square and it fitted within a few milimetres!

Next step was deciding the type of aquarium pump I needed.
I thought that since bigger is better (usually is, one good thing about those yanks )
I got me an Eheim 1250. 1200 litres per hour should suffice for the plans I got.

I read an article on the net about so called 'air traps' that double as a reservoir.
That was an idea worthy of stealing. I bought some similar stuff, glued it together,
used silicone to waterproof it and made my own 'airtrapavoir'
The system would be a closed system, but that meant that as the water would heat up and expand,
you'd get a certain pressure buildup.
No matter how small, a continuous pressure can and eventually will create leaks by flexing of the seals.
So I stuck a little Praxis balloon on top of the airtrap for overpressure and presto…

Have you ever had that you were so hungry, you'd pile up food on your plate and still thought it wasn't enough, only to find out you
couldn't even finish what you had?
This was a bit similar. I discovered the combination pump/reservoir was way too big to fit inside my PC casing.
I found out earlier that the rad was also too big to fit inside, but I considered mounting that on the back of the PC or something.
This latest setback was too much, plans needed to be changed rigorously, but how?

So after a couple of sleepless nights I decided to make the project external!
I found a good solid aluminium casing at Praxis that looked just right.
It took a while before I found the ideal way of mounting all the stuff
inside, but then I could finally start making some holes for the radiator and
the fanblock.

The fans needed to be able to run at the full 12 volts, but also go into
'whispermode' for when I sleep. The answer lied in a small transformer that
could supply six different voltages from 12v down to 3v and a simple rotary switch.
I took it apart and figured out the best way of mounting and connecting it.

Then came the great day of assembly. I drilled all the required holes earlier,
measuring as closely as I could. I stuck all of the components in there, took them
out again and stuck it all back in in the right order, hooked it up and tested the

The test was a great success (well, more a bit of a waterballet… but successful nonetheless).
I did notice the water heated up real good with no fans running and no heat source ... damn... Apparantly the 28 watts the pump uses
go straight into the water as heat. Looks like running the system with fans off is out of the question.
I considered switching to a lower output version Eheim, 1046 or 1048, but I really needed the maximum waterflow as I will explain later.
(Well, maximum flow within reason, there was also a 2250 liter/hr pump but you can overdo it)

The radiator fins needed some protection against bumping into stuff just as the fans needed some sort of penis guard.
(sticking your fingers between the fan blades just stings... get your weeny a whacked at 2000rpm and you'll go through the floor!)
Anyway, it needed too be just strong enough to keep stuff (like penises) from getting mauled by the fans, but thin enough to create as little
airflow restriction as possible.
The best material for that is Praxis chickenwire. I bought a role, cut a piece from the inside and brought the role back for a full refund .
(don't forget, the idea was still low-cost, can't get much lower than that! It wasn't very nice of me to do, I know that)
Then I cut two pieces in the right size, spray painted them black in my own little spraypaint studio...

...and presto: cheap, lightweight, flexible fingerguards/rad protectors

The next step was soundproofing the whole lot. At first I mounted the pump directly, and firmly, to the case. But the case acted as a
soundboard for all the nasty vibrations and hums.
I tried to leave the pump free floating inside the case and let the hose and reservoir connection become the bearing pillars.
This worked just fine, most of the vibrations were gone. I just pray it holds together...
It still needed further soundproofing though. I bought a packet of soundproofing eh… foam-stuff... yes, Praxis again...

…cut it into pieces and stuck it everywhere I could find an opening.

And these are the final pictures of what the Mobile Heat Exchanger (MHE) looks like on the inside and the outside.

Read part 2: The MOAWC (the mother of all water coolers)