Originally Posted by Unicr0nhunter
Just look at Martin's rad in the "Galvanic Corrosion Explored" testing he did in the link I posted. With water left stagnant in it it was ruined, and that's not mixing any metals other than what's in the rad. He explains why it happened and also gives several other examples. I've seen similar in many posts here and elsewhere, sometimes in a matter of months. If you leave your system off with no corrosion inhibitor additives for any extended or frequent periods of time and you didn't experience corrosion issues, then you got lucky or you just missed noticing it yet. Even with an anti-corrosion coolant/additive you're not out of the woods, you're just slowing down the reaction taking place.
What we have here is a case of one trusted tester/reviewer showing specific examples of corrosion damage linked to stagnant (not moving) water left in a loop, versus people saying they've done it and nothing bad happened to them. I liken that to all the evidence and examples out there that texting while driving is dangerous and leads to accidents, but then you have people admitting that they have texted while driving and they never wrecked, so it must be safe.
No, what we have here are different reported outcomes from vastly
different scenarios. And I would respectfully submit that you are taking an exaggerated conclusion from Martin's article
that is not part of what he wrote. FWIW, the article we're talking about is not a testing article and does not contain any experimental results. It is purely informational and explanatory, and gives a few interesting illustrations of the havoc that galvanic corrosion can cause in extreme cases.
You are far overstating the danger that brief periods of rest can cause by pointing to Martin's example of a radiator that was left sitting with water in it for a year
(see below). His article used that extreme, isolated example of corrosion (in his words, "not at all typical") as a jumping point for a very solid, general discussion of the risks for galvanic corrosion in a typical PC watercooling rig, and what can be done to reduce its impact. But he did not use the story of his corroded radiator as evidence in any way, nor did he discuss how frequently you should turn your loop on or off, which seems to be the point on which you are citing this article in support of your view. Where he did mention fluid stagnation, it was about minimizing areas where flow can become stagnant while the pump is running, not time periods where the whole loop sits without circulating. I think we agree that it's not a great idea to leave things off for extended periods, although we might have a different view of what qualifies as extended, and we disagree strongly about the risk from having things off "frequently".
Also, the analogy to texting while driving is a poor one since that is an all-or-none binary failure scenario where you take an avoidable, unnecessary risk, and either have an accident, or you don't. Galvanic corrosion is an unavoidable, gradual, continuous process that occurs in everyone's loop, that builds up over time. It cannot be prevented entirely, only slowed down. Over small time scales its impact is negligible under normal conditions. With proper maintenance, replacing coolant every now and then, also considering that most people rebuild and swap components entirely every few years, it's perfectly safe to turn your loop off according to normal computer usage patterns. FWIW neither I nor the other poster who disagreed with you claimed that absolutely zero corrosion was occurring in our loops (texting and no accident = turning loop off and no corrosion), which is what that analogy would also require in order to be accurate.
So my disagreeing with you is not "people saying they've done it and nothing bad happened" because, for that to be true, I would A) first have to have "done it", meaning, left a radiator with water in it on a shelf for a year, and B) claimed that zero corrosion occurred in my gear during the brief times it wasn't running. Neither I nor the other poster who disagreed with your conclusion did either one of those.
As a side note, since Martin doesn't mention precisely how long the radiators had sat undisturbed, it took a little bit of internet sleuthing to figure out that it was around a full year, and I am now going to explain how I came to that conclusion. Partially because, it's my personal policy to think twice, do a little research, and double-check myself before I post pretty much anything. But also because I take great pains to never put words into someone's mouth that they didn't say. Skip this part if you like. I have enclosed it with spoiler tags to reduce screen clutter:even more long-winded discussion (Click to show)
Edited by threephi - 3/9/14 at 2:48pm
The article on corrosion is dated January 24, 2012 and says the radiators were sitting with water in them, unused, since an unspecified fan testing series "last year". It being only January, that could have meant only a few weeks. He also describes retrieving the rads as "digging [them] out," which to me implies it was a couple of months or longer, but it's still quite vague.
His Round 9
testing series is dated April 28, 2012, and the Round 7
140mm testing series is dated December 10, 2010; therefore he must have been referring to Round 8.
But there's no link to a Round 8 on Martin's site. A little clicking shows that his post labeled Round 6
is, actually, the combined results from Round 6 and Round 8, as the jpeg image
at the top of that article shows. The Round 6+8 article is dated November 4, 2010, which must represent the original date for Round 6, as it is earlier than the date for Round 7. So now the question is, when did Round 8 happen?
The Round 6+8 article's second page
contains a long list of links to the specific data for each fan Martin tested, all contained in a thread on another watercooling forum
. Identical to the article on his site, this thread is titled as Round 6 but also combines the data from Round 8.
The original post date for that thread is November 4, 2010, which matches the date on the article on martinsliquidlab.org. But the "last edited" date at the bottom of the first post is January 8, 2011. Other posts towards the end of that thread confirm that Martin had nearly finished Round 8 testing in late December 2010
, and had finished the update
on January 8, 2011. Later that month he also stated
that he intended to take a break from fan testing, which lends further support that the equipment used in Round 8 sat unused for a long time.