First Project! [Custom Res, Heater Core, Eheim pump, EK Supreme HF]

[Nullspace]

Hi all,

I'm John, and this is my first project.

Watercooling rigs are almost always about performance. Aesthetics, as far as I have observed, only seem to come into play when deciding where to run the hose, what colour liquid/hose to use, and how to modify the case. The projects i've seen on this forum and others have indeed been incredible to look at, but very few of them actually do something interesting with the water itself.

When I was much younger I can remember seeing a supercomputer at one of the local universities. It may have been a cray, or a fuji, or SGI or something or another; but although my memory is dreadful, what I do recall is seeing the coolant cascading behind an acrylic/glass 'window'. Since then i've had idea after idea about designing enclosures for systems that use the water as part of the design itself.

This first project of mine is quite likely the most basic idea I could think of. I would create a reservoir which cascaded water over the edge of a platform in a way similar to what I had seen before. I was working on a budget, so rather than buy WC designed rads and build an acrylic box from scratch (good acrylic can be damn expensive!) I opted for the following...

EK Supreme HF plexi (the most expensive item in the system)
~1996 (I think?) Renault Clio heater core (5 pounds on ebay)
A 25x25x30cm glass fish tank (10 pounds)
An Eheim 1046 pump (Low pressure - needs exchanging really, but was a bargain at 25 pounds on ebay)

Now before I go into the construction i'll post a couple of pics of the project in its current state:





The system is an i7 920 on a P6T, and is currently running at 4.2GHz, 1.375v, average of ~75c under full load.

The first thing I did was to make a rather ghetto shroud for the heatercore:



The beauty of this core was that although the fins are clearly aluminium, the piping is copper throughout. I was a little worried about the density of the fins, but the two 140mm fans seem to cope with it easily (and quietly).

The core also came complete with plastic, barbed hose connectors. Although I was able to stretch (with difficulty) some 1/2" hose over the intake line, I had to jerry together a solution on the return. What I did in the end was use some pvc/acrylic glue to water-seal a piece of pvc electrical conduit to the inside of the return pipe. I then stretched 1/2" hose over that section. The result is very tight, hasn't leaked a drip in well over a week and a half of playing around with it, and required no cutting/tapping/brazing/whatever.





Yes, thats duct tape, and yes i'm aware it looks awful. I plan on replacing the shroud with a nice acrylic box when I have the time/money.

Leak testing/cleaning it:



I have no pictures of the rad with the fans fitted, but I purchased two akasa 140mm s-flow fans... sorry, I forget the name off hand. They were ~10 pounds each and came with rather uselessly short cables. I cut both cables, and used a length of outdoor (black) phone cable to take both power feeds (two cables each) into the case and to my fan controller. Again, no pictures of this as of yet, sorry, but it works pretty well.

Next I started on the acrylic:

I wanted the acrylic to look as good as possible and so I spared no expense, buying A4 sized glass-look 10mm cast acrylic from an ebay supplier. It was rather cheap in the grand scheme of things, but at 4 pounds a sheet it's expensive compared to other plastics.

Cutting it with a drill was an absolute breeze. I used a 20mm wood-boring flat-spade-bit to cut the two bulk-head holes. One would be feed and one return. I realise that having a gravity feeding res with the return at the bottom of the tank would be ideal, but I wasn't about to start drilling through 3mm glass.



Next I cut, filed, and polished another A4 sheet so that I could build the tray:



In the above image it is taped in place ready to be bonded. Working with this stuff was a real pita! I had only very basic tools to my disposal. No blow torch to scorch-polish the edges, no belt/circular sander, and to begin with not even a jigsaw. The hacksaw was proving to be impossible so instead I borrowed my brother in laws jigsaw, bought myself a fine tooth metal-cutting blade, and threw it at the plastic. It cut it very straight, although on my first attempt I was a little wavy. Practice makes perfect.

The pieces were then painstakingly filed until most of the cut marks were gone, and then sanded up from 120 grit through 180 to 400 grit wet/dry paper. I used some locally produced ebay-sold damned-if-i-can-remember-the-brand acrylic/pvc glue to join the edges. Had a quick curing time and was water tight by the next day.

The shelf is held to the lid via four bolts, supported from underneath by the nuts themselves. I was worried about galvanic corrosion so as I could only get hold of zinc plated bolts I wrapped them to buggery in PTFE tape before eventually putting the system together. Still though, the nuts themselves are starting to corrode a bit (I think), so i've ordered some M6 nylon bolts instead.

Here is the lid/shelf system 'together' (sans PTFE, and the black electrical tape is still in place until the bonds cure.):







I used a 16mm flat spade wood borer to cut the hole for the return-pipe. The water is fed (in the finished loop) through a length of 1/2" hose, vertically through the shelf (water-sealed with PTFE) and upwards to the right-hand bulkhead. You can see the g1/2 barb on the right hand side ready for the hose.



Acrylic is messy.

Had a few problems during leak-testing. The rad/pump must have still been full of gunk because not once but twice did I have to dismantle the waterblock to clean out bits of this crap:



Other than that, leak testing went fine. I should say though to anybody ever considering a design like this - priming the pump is an absolute (you can't swear here, can you? - you get the idea). I wish that i'd put a t-line before the pump, because since this res doesn't provide a 'gravity driven' system, you have to work out your own weird and wonderful little way of filling the loop. I managed to do it, and have a bit of a method down now, but like i said - t-line all the way.

Temporarily, I installed some ikea lights under the tank. I'll mount these properly in a sheet of rubber or acrylic when I get the chance.







The water drips off the shelf and it all sounds very nice. The 1046 is a little low on the flow, however, and I'm not getting the desired 'sheet of water' effect I was after. I think i'll replace the pump soon.

And the complete system again:



As you can see I like rack mounted cases. The 'rack' is a lack-rack (google it) - basically two lack shelves from ikea stacked and sided with MDF. The rad is screwed to the side through two 5mm rubber washers to isolate it (its pretty silent with those big-ass fans). I plan some modification/painting of the workstation when I have the means, but right now i'm afraid its just plain old stock. For anyone curious, the 8 racks below are dell poweredge 650's. They're only P4's - an institution here was getting rid of them and couldn't sell the bloody things, so I and a friend brought some home with us to play around with openMPI - still aint gotten around to it though, lol. (They are bloody LOUD).

Okay then! I think thats everything - I'm rushing here... oh.... problems!

Problems

Can someone please tell me why the hell my water has gone cloudy? Right now i'm just using plain jane distilled, although it has since become contaminated/ionized (tested with multimeter). It can't possibly be corrosion as the loop has only been running properly for two days, and most of the zinc bolts are completely sealed. Could it be air bubbles? How about some sort of infestation?

I think i need to re-fill the system but add some anti-bacterial agent. I wanted to add a dye bomb to it - are any anti-bac fluids clear in appearance?

Here's what I'm talking about:



Okay, thanks! And erm... this is my first ever post so, nice to... meet you?

John