grounding waterblocks

[dogbait]

Should a waterblock ideally be in contact with ground or not? (ie. the standoffs or screws that make contact with it should be in contact with the soldered holes)

On my Leadtek GF4 card, there's a small spring on the back which makes contact with the heatsink grounding it. As is there on some Matrox graphics cards, which have a small wire connecting the HS to ground.

With mixed metal blocks, (Swiftech and DTWW) should the block touch ground or be completely insulated?

Would the water itself provide a ground path?

And what would be the ideal situation amongst the above in order to minimise any potential difference across the copper/aluminium?

[SexyMF]

Unless ground loops are a problem then I would not worry about it. As you say, the water connects the blocks anyway. Isolating them from case earth is not needed.

[Dunno]

A little off subject but:

I have been thinking for a while that grounding water blocks and heatsinks may give one more stability as you decrease EMI.

Didnt Intel bring out some sort of standard about earthing and shrouding their CPU's to minimize EMI??

[ndtinker]

Water touches the block, then probably next would be the radiator, if it was bolted to the case, or even the Res for those who have metallic ones lying or bolted somewhere, so it's probably grounded without even trying.

[orev]

Grounding does not occur through the water to anything if you've set up your system correctly (used water wetter or antifreeze). The whole point of additives is to stop electrical conductivity.

On the grounding thing in general, it is totally unnecessary. It's good to see someone was thinking about it, but there's no electricity involved in a water block (I hope!)

[LtBlue14]

well sure there's no "electricity" to speak of running through the blocks, but the battery effect is real, and i don't know if grounding waterblocks reduces it or not. i don't actually think it does, because as someone else pointed out, waterblocks are grounded via the water which flows through the heatercore which is touching the case. also, water additives like antifreeze are supposed to prevent the battery effect. water wetter = crap b/c of the film it leaves on everything. it's gross, can kill flow in a block like the white water or cascade, and makes your tubing rather opaque and gross

[dogbait]

Well, thinking about it, it would seem that grounding the blocks will simply provide both copper and aluminium parts of the block an infinite supply of electrons. So, in effect there will be no net change on the overall battery effect since both copper and aluminium have had an equal amount of 'ground' applied to each of them:

eg.

al + ground = copper + ground

(therefore 'ground' cancels out to give)

al = copper

(hope that makes sense)

But grounding blocks should have some positive EMI effects, especially when they're so close to the CPU. For anyone who hasn't read Chieftec's factory tour at THG, it seems that no matter how small a case window a PC has, it will not pass their EMI tests. Scary...

[Since87]

Originally posted by dogbait
For anyone who hasn't read Chieftec's factory tour at THG, it seems that no matter how small a case window a PC has, it will not pass their EMI tests. Scary...

The window will pass the test if it is coated with indium-tin oxide (ITO) and a connection is made between the ITO and the case all around the periphery of the window. Would likely make for an expensive window though. I've gotten quotes of about $2.40 for a 2"X3" ITO coated window in 1000 piece quantity.

Edit: BTW, your comments about grounding copper and aluminum don't make much sense to me. Grounding both is equivalent to shorting them together. Not what you want to do with the two terminals of a battery.

[dogbait]

But in the Swiftech case (what I was referring to in my mind) the two halves of the block (Al and Cu) are bolted together, so the 'two halves of the battery' are already connected together.

I simply said that grounding the block would have no overall effect on the following cell:

Al| Al 3+ || Cu 2+ | Cu

Feel free to poke holes in my logic.

[Since87]

Originally posted by dogbait
But in the Swiftech case (what I was referring to in my mind) the two halves of the block (Al and Cu) are bolted together, so the 'two halves of the battery' are already connected together.

I simply said that grounding the block would have no overall effect on the following cell:

Right, when the copper and aluminum are already electrically connected together, grounding has no impact on corrosion. I wasn't following what you were trying to say.