Fleaker
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Bath circulator corrosion
I just purchased two nice Neslab chillers which function perfectly. Cosmetically speaking they look fine, but upon closer inspection I see some
corrosion on the cooling coils on one of the units.
The coolant reservoir is stainless steel and is in good condition, but I do not want any rust on the coils because it could hurt the pump and it could
possibly continue to propagate.
What is the best thing to clean out the rust/corrosion? I was thinking that I should gently wire brush off as much as I can with detergent, but after
that I'd like to chemically remove the deposit. It seems to me than an ounce of prevention would be worth a pound of cure with these units. They both
function perfectly, but I think if I leave the corrosion in there, it's only a matter of time before it affects performance.
Any advice, suggestions, comments?
I can post photographs if necessary, just ask!
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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not_important
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Are the coils stainless, or aluminium?
If steel, a warm solution of citric and ascorbic acids will reduce ferric to ferrous and dissolve common corrosion products as well has deposits from
hard water. After that several rinses, a short soak with dilute NaHCO3 or Na2CO3 solution, with a trace of Na3PO4 or the silicate if you've got `em,
rinse again.
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Fleaker
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Stainless based off the look of the corrosion. That's exactly what I was thinking remedy-wise. I'll give it a try tomorrow.
50/50 ethylene glycol:water is good for -30C, correct? Just want to make sure 
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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not_important
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| Quote: | Originally posted by Fleaker
50/50 ethylene glycol:water is good for -30C, correct? Just want to make sure
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grab the PDF here http://www.ashland.com/pdfs/technical/AD%20Chemicals%20-%20F...
Remember that ice crystals can form above the freezing point, which may cause pumping problems including clogging of smaller tubing and openings.
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chemrox
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I"ve been told that oxalic is also good for reducing Fe salts is this the case or no?
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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S.C. Wack
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I've used the usual OTC somewhat perfumed bisulfite/dithionite to take out rust stains on several areas for some time, including inside condensers and
in the recirculating aspirator pump. Works great. The OTC dithionite (not perfumed) for water softeners is faster but more expensive, and it isn't
likely anywhere near proper fresh dithionite anyways, given its quite foul odor.
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Klute
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Oxalic acid works great for removing rust staines! I alwya use it for cleaning the old rusty metal pieces used to hold the aluminium bars together,
after a hours soak and a little scrubbing, they are good as new! All shiny and clean...
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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garage chemist
chemical wizard
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Don't use glycol/water mixes for temperatures below -15°C, they become very viscous and the pump will have a hard time pumping it, while the heat
transfer is bad as well.
Denatured Ethanol is a very good bath fluid down to -50°C, while methanol can be used down to -80°C while staying as fluid as water.
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AJKOER
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Perhaps a medical approach might work here.
Get some detailed history/background data: general health history most likely associated with the bath's location (there may be known issues
associated with that city, climate, region,..like smog, ozone pollution, chemical waste,..), more precise family history (your water is from a lake,
well, river, reservoir,..or mixture therefrom like mine), common medications that your water is on (Chlorine, Ozone, Chloramine, Hypochlorites, O2
from aeration,...), past conditions (high levels of sulfides, iron, minerals,..), recent changes (industrial development, community growth/decline,
government budget cuts...).
Then, a picture showing detail effects of the condition.
Then, a professional (in this case a chemist) diagnosis of what is causing the problem, followed finally by a prescription that is known to treat said
condition.
There may even be a suggestion for preventive medicine (like a water softener, filters,...).
Actually, following this procedure may mean that your bath is going to receive better treatment  than you do for what ails you  .
[Edited on 3-3-2013 by AJKOER]
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feacetech
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I use to work for Ashland
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