Copper, Aluminium, Silver and Flourinert = Problems?
 

I'm contemplating a setup with the following:

1 x Cascade G5 (Silver) (1/2")
1 x Eheim 1250 (1/2" out)
1 x acrylic res
1 x '85 ford van heatercore
1 x AquaComputer Twinplex northbridge (CU) (6mm ID)
1 x AquaComputer AquagrATIx (AL) (6mm ID)
1 x Silentstar Dual HDD cooler (CU) (6mm ID)
1 x custom VRM block (CU) (6mm ID)
1 x custom H2O cooled PSU (CU) (6mmID)

Flow as such = res -> pump in > pump out > G5 > 1/2 to 4x6mm splitter:
Split 1: Northbridge
Split 2: GPU
Split 3: Silentstar
Split 4: VRMs+PSU
Recombine to 1/2" -> res

copper+silver = not a problem
copper+AL = problems (can be countered to some degree with anticorrosive agents)
silver+AL = BIG PROBLEMS (can't be countered easily with anticorrosive agents)
copper+silver+AL = "RUT ROH RORGE" (bad)

Can I get around this problem by using flourinert? it seems if the distilled water were replaced by an inert substance (3m flourinert PF-5080), would the galvanic corrosion still occur? I'm guessing no, as the silver and copper are still in wetted contact, but the flourinert wouldn't take any ions from the copper or the silver to corrode the aluminum.

Help is appreciated :)

Plenty of quality copper stuff out there. After the trouble of creating it in the first place, why have long term worries.

Well, as much as I'd like to make my custom stuff out of copper, its a bitch to work with. Aluminum machiens much easier on my half-ass millpress setup.

Only AL part listed, custom pieces listed as CU.

Whoops, my fault there.

flour-inert is made with wheat? :)

With Fluorinert you should get no corrosion, as it does not conduct electricity and does not react to, or bond with anything. Cools like an SOB too --because of its very low surface tension it makes good contact with blocks and rad.

Oh, and it doesn't turn your tubing opaque. :D

Damn you nexxo, gotta be pickin on the opaque white tubing :)

I suppose you're the source.

Possible issue with florinert - evaporates very easily, unknown how permeable tubing is to it long term.

I haven't checked cost and availability lately, but the stuff used to fetch a kings ransom, if you could get it. If I were going Fluorinert, I'd just go to direct die cooling and skip the "middlemen".

Hoot

There's also Galden, yet another fluorinated fluid...

It may have the surface tension advantage, but the numbers I saw show flourinert to have a very low specific heat. (.23 or thereabouts). Straight ethylene glycol is ~.6 and 30/70 glycol/water is ~.9, so that is pretty significant.

In that case, running straight anti-freeze might be a better (and much cheaper) option. I don't know if that helps the Al-Ag situation however.

If the fluid dissolves metal very much, you may get corrosion even if its not conductive.

I'd say figure out a way to eliminate the al in the loop. Perhaps an alternative block from danger den? If you want a better quality block look around the extreme system forums. There is a guy there who makes his own gpu blocks. Charges reasonable prices and needs like 2 weeks of lead time. (I'd give you the link to one of his threads but I'm too lazy to look right now). Flourient is very expensive. Sometimes you can find it on ebay. Its cooling performance isn't THAT great. The lower surface tension helps but I can't imagine that it helps enough to overcome its substantially lower specific heat capacity. Certainly not worth what you pay for it in my opinion.

Oh, yea of little faith... Yes, Fluorinert does evaporate at room temperature, but I've been running it in an ordinary closed system for a few months now and the level hasn't dropped at all (and I measured it carefully). It does not permeate the tubes (I mean, really...). And it does not dissolve metal. It's that whole inert thing, geddit?

As for the low specific heat and performance issues... all I know is that I cool a dual Opteron 250 and a Radeon 9800Pro on a single BIX with a low-flow Panaflo (69.7CFM) --that is about 220Watts-- and I get temps of 40C to 45C. Your mileage may vary, but it sounds pretty good to me.

It may be pricey but at least I will never have to drain and clean the system. And in the unlikely event of it spilling all over the system I rather lose £70,-- of PF-5080 than a couple of thousand pounds in short-circuited hardware. So as for it being worth the money: you make your choice and you pay your price...