Being a pc watercooling nerd, it was a no brainer to reuse old parts i had, and get a watercooled spindle. Having discovered the spindle water jacket is made if aluminium, i had a search in my "box of bits" and luckily had an aluminium radiator. Pump and reservoir are all plastic on the water contacting parts. However, the compression fittings etc which i have, are all nickel plated brass, and so are all the ones i can find online. To be honest the compression fittings on the spindle itself look to be the same, which is a complete no-no, unless you want galvanic corrosion. I did find some plastic fittings, but they are "push fit" which i have had bad experience with in the past (leaky!) How do others approach this? I will of course use corrosion inhibitor, but that is only partially effective..
adding the correct antifreeze for an aluminum engine block is probably the easiest way to prevent corrosion.
I'm not familiar with any of the water based spindles.. but you can only get galvanic corrosion when a charge is run through the fluid which contains metals that are dissimilar. The water that you are running through the pump should be a closed loop and no current should be running through it... if there is.. it would be due to a short somewhere.
The current which flows through the water (an electrolyte) causing galvanic corrosion comes from the differing aniodic index of the two metals.. The further apart they are in voltage potential the worse the corrosion risk is. Unfortunately aluminium and copper are very far apart. Its more or less how batteries make electricity too. No external power source needed.
It's based on the electronegativity of the dissimilar metals in an ion-permeable solvent medium, doesn't require an external charge- think lemon battery or old-school pressure-treated lumber. Hence galvanic and not electrolytic. The "correct" way to do it, I believe, which is probably also the most expensive way, is to have your loop 100% insulating PC coolant. If you have a small loop, radiator and reservoir, that's more doable. Otherwise, I'd agree with the aluminum engine block coolant idea. Of course, there are plenty of people that claim they've done 50:50 regular antifreeze and distilled water for years without problems, so it's a bit of a toss-up. I've looked into this quite a lot the last few months to try and get an idea of a "definitive" solution, but such doesn't really seem to exist. Fortunately these spindles are only $200 or so, it'd be really unfortunate to gunk up and toast a really expensive one like the ATC spindles or something.
Ive actually got half a litre of fluorinert sitting on the shelf, kindly provided as a sample to me years ago for a project which never went anywhere, however i dont think thats enough, ive heard it eats plastic tubing, evaporates faster than alcohol, and is generally not nice stuff, also insanely expensive, so i think it will stay in it's (aluminium) bottle for now. Automotive inhibitor here we come!
ok so, something has been bugging me: everyone suggests automotive coolant.. designed for ally engines and aluminium radiators... cool! but, what about central heating corrosion inhibitor? for example fernox f1 https://fernox.com/product/protector-f1-500ml/ it is designed for mixed-metal use, specifically heating systems with copper pipes and aluminium/steel radiators etc.. its obviously different from the automotive stuff... the generic g11 automotive coolant i have at home is a "concentrate" but suggests a 1:1 ratio with distilled water... the fernox f1 guide suggests a 0.5 percent concentration.... anyone here nerdy enough to tell me the difference or why one is better than the other?
