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Temperature Probe Oxidizing?

Hey, guys...I'm a frequent poster on rec.crafts.brewing, but it seems that my brewer friends haven't taken a stab at my latest question. It has way more to do with metal than brewing, I suppose, so maybe some of you guys can help me out. Any input would be appreciated. I'm just going to paste it here as is, and see what you guys think. (FYI, A carboy is just a 5 gallon jug used for fermenting, and lagers are supposed to be fermented at temperatures lower than room temperature, so that's why my carboy is in the chest freezer...Oh, and a blowover hose is just a hose coming out of the carboy into a jar of sanitary solution to collect extra stuff coming out of the carboy during the initial stages of fermentation...:o)

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I have a chest freezer with a Johnson Controls thermostat. Since all my kegs have kicked, I decided to use the extra space for another lager. I brewed it up sunday, and my only available carboy was 5 gallons; I needed to do a blowover hose arrangement. I have the other end of the hose in a jar with a light bleach solution (about a tablespoon or less of bleach in about 10-12 oz of water). The blowover's been going on much longer than expected (this is day three), and I've cleaned and refilled the jar three times. But the probe to my thermostat is getting green and brown spots all over it! I can't seem to clean these things off - it's been a while since I was in the jewelry business, but this looks like oxidation. Plus, it's set at 55 degrees, but my 'fermometer' on the carboy is reading 62 (probably just the exothermic reaction from the fermentation), and a thermometer I have in the fridge is reading 58.

Are the fumes from the bleach destroying my temperature probe, or is this something I shouldn't worry about?

That Thermostat wasn't cheap - :o(

Any help would, as usual, be very much appreciated.

Thanks,

Chris Aponte

Reply to
Chris Aponte
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If the thermostat you are describing is a bulb type standard thermostat it is probably made of copper, but might be plated, so it will be affected by a bleach solution ( chlorine ) If there is plating on it, chrome or nickel, it will be very thin plate. Should not be a problem as long as it does not actually eat right through the bulb, if it does the thermostat simply will not work at all. The bulb is just like that in an ordinary thermometer, a liquid expands inside it and travels through a capillary tube to the thermostat switch mechanism. If the fluid leaks out it is bust and not realisticly repairable. So just wipe ti clean, don't be to rough with it. possibly paint it. Hope that helps, Mark.

Reply to
Markgengine

That was extremly informative, and helpful. Thanks very much, Mark!

It looks pretty messed up at this point. I think an extra layer of some coating would be helpful.

If I do decide to paint it, what should I use for paint?

Will the paint affect the way it measures the temperature?

Thanks again,

Chris Aponte

Reply to
Chris Aponte

A good quality epoxy paint should be as good as it gets.

No - other than to very slightly slow down its reaction time to temperature change - seconds not days.

Ted

Reply to
Ted Edwards

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