What is that?
That was a little frankensteinian experiment gone horribly wrong.
It started with an old K6 350Mhz and an all-in-one baby-AT motherboard that somehow got "donated" to me. First I swapped out the heatsink on it for a Zalman 6000AlCu that I laying around. Worked great passively cooled that way, but it wasn't silent, the PDU and HDD were still making a racket.
So I came across a radical idea....Mineral Oil Cooling. It's essentially Baby Oil. It's been used for computer cooling before, mostly by people looking to seriously overclock, but I wanted to take it a step further. The people who've reported using it before either used it with conventional water cooling blocks, or submerged just the motherboard in it. my plan was to submerge the whole computer
: motherboard, PSU, HDD, everything! I built an acrylic cube 10" square and mounted the motherboard in it. Then I uncased the PSU, so it's just the bare PCB and heatsinks, and put that in the box. After sealing the breather hole on the HDD I put it in there too.
Then I filled the box with 3 Gallons of Mineral Oil.
Made a couple of interesting discoveries:
1. Regular computer fans will still spin while emmersed in Mineral Oil!
2. You need to seal more than just the breather hole to make a HDD watertight.
I tried a couple of other methods to seal the HDD, including gooping the whole thing in silicon caulk (The Mineral Oil dissolved it
) and dipping the HDD in that rubbery stuff you can buy at the hardware store to dip tool handles in. (The Mineral Oil made that stuff return to liquid
The last attempt was to cast the HDD in a block of acryllic. Now that worked perfectly. (It's Alive! It's Alive!) With the HDD noise blocked by the 1" of cast acryllic AND resting in the oil it was completely totally silent. The machine ran just fine like that, for a while. Turns out that the system was producing more heat than could be radiated out through the acrylic box. If the box was metal it'd probably be fine. So the temps slowly rose. I monitored them with an aquarium thermometer I suction-cupped to the wall of the box.
The temps eventually stabilized at about 55°C. Which the CPU didn't mind, but the HDD fried itself. Given the insulating blanket of cast acryllic it was probably even hotter than that inside there.
So after killing 4
harddrives I decided to give up on the idea of submerging that part. In the current machine the HDD sits in a foam box (the foam my new Seagate came in) on top of acryllic box full of oil, not in it. It'd quiet, but by no means silent.