Thursday, January 22, 2015

PC watercooling loop upgrade and update

Approximately 4 months have passed and I was looking for a new job again (dear ex-employer: fuck you) so I finally had time to finalize the project to what I consider version 1.0. Well, the real reason I did it was because of this:

The glue decided to take a break

The glue in top back edge of the reservoir decided to let go, forming an approx. 5cm crack, some 0.35mm wide. Small enough to not get noticed in the case and above the still waterline, so it probably was there a while since it had no reason to leak. Because of the way the system was kludged together, some time later I had to lean the case backwards a bit to keep the pump from sucking in small bubbles. (It makes noise when that happens) The result of this was that a puddle of water began to form on the top of the reservoir and started to drip down. Luckily nothing got destroyed, the PC did however crash, which was why I was examining the insides and found a puddle of water on the bottom. Not a very pleasant feeling I tell you...
Because the loop had to be drained, (top tip: if you need to drain your loop and don't want to make a mess, use a vacuum cleaner that can deal with water) I went ahead and decided to put the L fittings in.
I also took the block apart to see how it held up.

Not so well...
At least the seal worked

The block does indeed corrode, I suspect that is because the CPU heatspreader is grounded, thus there is potential between the brass fittings (which are connected to the hose braiding and that touches the case). Anyways, there is no measurable loss of material (the bottom is still almost 2.5mm thick like it was before) and judging by the amount of oxides, I will make a new block well before the old one becomes anywhere near being eaten through.
The only downside is lost cooling potential. I am running a FX-8320e and the temperature stays around 30°C at 18°C ambient temperature while idling, at full synthetic load it fairly quickly climbs to around 38°C and stays there. After terminating the load, it quickly falls back down, indicating that the block has a fair bit of heat resistance. Hopefully a new block will fix this, but overall I am very satisfied with the performance, the true test will come when summer hits and the ambient temps rise past 35°C...

After scrubbing the oxides off, I began reassembly.
These allow the L fittings to rotate without moving the threads in the plastic
In all its glory

This time, the block is sealed by air-curing neutral silicone.
Beware that not all silicones are ph neutral, most are acidic and corrode aluminium!

Block, it's hoses and pump are in

Radiator with fans (on the inside), reservoir and more hoses added

As if failing once is not enough...

I hate acrylic/CA glue as a building material. This will get replaced in the next version.

Complete with filling solution
Additions to this version include a fillport with ball valve and a T fitting at the pump. Forgot to take pictures with the graphics card inside. Some other day...

You will need these tools to complete the build

The crapload of wrenches is necessary because of the 3 different nut sizes, the universal one is needed because of limited space between some fittings where normal wrenches simply do not fit.
Next is an hex bit with holder (screws in the CPU block), the big hex key is to screw in and tighten the stationary part of the L fittings into the block (their inside is hex shaped) as there is no other way to do so.
Teflon tape is to seal the fittings in the plastic, everything else uses squishy silicone ring seals (blue box top left-ish).
Needle-nose pliers and screwdrivers to fix the heat exchanger in place, neutral silicone to seal the block itself.
Hose with screw-on L fitting, funnels, clamps and measuring cup to fill the loop. btw the coolant now contains about 10% non-toxic anti-freeze (some weird mix of various more complex alcohols, the pure form is quite sirupy) to keep algae and other crap out. Or at least dead.

Version 2.0 will feature a better block design that uses copper in reasonable amounts (thus being cheap) and most likely a graphics card cooling solution. I'm still toying with the idea of making the CPU cooling direct (water directly on the heatspreader), as it would drastically improve the thermal resistance problem and make the thing smaller.

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