Rust suppression in a radiator, suggestions?

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dinnerstick

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I'm pumping water through a radiator for heating and cooling of my fermenter, and the water comes out black. after one full fermentation run the hoses (beer line) are opaque black/rust red. does anyone know what would be good to run through this system to stop the rust? there is no chance of contact with the fermenting beer so it can be as poisonous as you like. the liquid goes through a small heat exchanger, radiator, and tupperware reservoir. does car antifreeze have anti-rust properties?? any suggestions welcome, thanks
 
You need to flush out the radiator. There's nothing in there to rust, it's all either brass/copper or aluminum, unless you've added something made of steel.

Antifreeze is a rust inhibitor.
 
this thing is steel, painted on the outside. no idea what it was originally scavenged from before it was re-scavenged for beer. if antifreeze is a rust inhibitor then problem solved! cheers
 
Use automotive antifreeze. It has rust inhibitors. Also you can add just a few drops of dish soap to the antifreeze. You don't want it to get bubbly and foamy. The soap will help reduce surface tension and promote better heat transfer.
 
You can get a corrosion inhibitor. It's a product that allows you to use straight water as coolant in your car if freezing isn't a concern. 'Water Wetter' is one brand name that I know of. Not sure how well it works but I remember reading about it in car mags. It gives you the option of using water as opposed to anti-freeze.
 
Use distilled water, it has the minerals removed so they cannot react with the steel and cause oxidation.
 
Use distilled water, it has the minerals removed so they cannot react with the steel and cause oxidation.

I know distilled water is recommended for use in rads, but I have to disagree with the wording of that. The minerals may leave deposits that build up over time (which is why you use the distilled water), but the water itself is what reacts with the steel to cause the oxidization (which is why you also use anti-freeze or some other corrosion inhibitor). Yes ? No ?
 
GreatWetNorth said:
I know distilled water is recommended for use in rads, but I have to disagree with the wording of that. The minerals may leave deposits that build up over time (which is why you use the distilled water), but the water itself is what reacts with the steel to cause the oxidization (which is why you also use anti-freeze or some other corrosion inhibitor). Yes ? No ?

I agree with that statement. Actually the more pure water is the more corrosive it becomes. We run in to this quite often in the commercial HVAC industry. The water removed from air in an air handler is pure and loves to eat steel condenser pans.
 
.Actually the more pure water is the more corrosive it becomes...

Not so actually. Corrosion reactions are often limited by the conductivity of the electrolyte, which tends to increase with the amount of ions in solution. Corrosion is an electrochemical process... not at all like dissolving some salt in water.

P Glycol is a mild corrosive on it's own. Been using pure p glycol in di water with an off-the shelf tranny radiator for many years however. I would recommend an inhibitor if it was certified food grade etc. Have not done the research, but I'd bet the ones sold by micromatic etc are good to go.
 
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