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Yes, that is exactly what it is doing.
The formation of the magnetite layer seperates the DI water and the metal surface. The concentration and quality of the Propylene Glycol DIRECTLY affects this layers' formation and resiliency, even in turbulent flow.
This is the grand trade off of W/C'ing. The better the magnetite layer, the less likely you are to have corrosion. But the inherent nature of the layer is to INSULATE, therby reducing (to a small degree) heat transfer capability. That is why a 100% DI water filled system will always transfer more heat than a mixed charge of fluid.
This is where you get everybody going off on a tangent about how much additive to use in the system. It is not a set amount. the concentration is unique for each application. The balance between protection and heat transfer is what everyone is trying to acheive. The concentration for my system will be drastically different than yours because of the sheer amount of metal in your system that needs protection. Therefore, I never jump into those threads where one person is asking how much additive they should add to their system. It is different for everyone. I choose to err on the side of 'overprotection', which means my heat transfer efficiency is lowered, but as long as I can attain acceptable temps for the application, there is little need to adjust the concentration. I have made a slight change in concentration (lowered) to try and get my UV dye to work better, but I'm still a bit high on the PG so far. My next charge of fluid will a little less PG to see if I can get my fluid to glow a little better, ehile retaining the level of protection.
BTW, you're pretty safe discussing this with me, my degree is in Nuclear Technology. I used to be Homer Simpson in the nuke plant, lol. My HTFF is too 'rusty' (pun intended).
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Thanks for the help, as you know it's hard to find anyone that actually knows what he's talking about to offer advice online. :D
If you had to put out a wild guess about how long deionized water would last before its resistivity dropped below say 5Mohm/cm in a WC system in which the only exposed metal parts are a waterblock and a radiator with say 2ft of copper tubing what would it be? How long do you guess it would last with the proper additives? How about in a system like mine in which almost every surface is metal?
Not that I'd sacrifice one iota of performance for a safety net in a situation like this. I put more faith in my designs, test procedures, and hands than that. I always use a harness when in a treestand, the alternative is just stupid, and I can lean off the side and get a better shot while avoiding my suit interfering with my cams. :D
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Honestly, without testing the fluid charge, it is literally impossible to tell. If you happen to have a wetprobe conductivity meter handy, it's a breeze. DI water and some kind of additive should ALWAYS be less than 1. If it isn't, your concentration is too weak or your additive is conductive.
I prefer to use the K.I.S.S. method: If your temps are acceptable, don't mess with it. Drain and recharge every 6 months. That is MY plan. I'm sure there are folks that go longer and some that go shorter.
I started with a simple 25% coolant concentration, but lowered it to 15% after my last charge. This charge will be 12% (The UV Dye started to work @ 15%, just wanna see if there is a difference).
Ahh, zack, love those hunting examples! Yes, agreed. Err on the side of safety and you will NEVER go wrong. Too safe? Doesn't exist.
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Oh, I forgot to mention how I test.
I've seen the pictutres of your garage, so I bet there is a coolant tester there. I have one of the spyglass refractive type testers. My current blend of 15% coolant (by volume) protection is around 0°F. My old charge with 25% was a whopping -15°F.
Test and record your current charge as a baseline.
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Thanks for all the info. I'm going to have to do some serious reading on all this before I get too involved with more projects.
