Accurate Hygrometers

[Steve Baker]

I want to know what everyone out there is using to accurately measure the humidity in their shop. I've been trying to learn more about hygrometers since all 4 hygrometers in my shop say different things by almost 15%. Is buying a hygrometer with a calibration button essential?  Any advise is appreciated

Dan

[Hesh Breakstone]

Check out this link to a thread that I started last week on the same subject:  Tis The Season...

[Steve Baker]

I couldn't see the photos attached but I looked up what psychro-dyne and am very interested if this is finally the tool to accurately measure RH. Any other info about ease of use or any links to videos about this you can share??

[Hesh Breakstone]

Steve I'm not sure if the psychro-dynes are even manufactured any more and mine came off from eBay and was clearly used (Bendix Aerospace inventory sticker on it...).  What the psychro-dyne is is one implementation of a "wet-bulb" test that can be done with two thermometers.  

A sling psychrometer is also another implementation of a wet-bulb test and these are currently manufactured and available for sale.

So the real method here is a wet-bulb test with lots of different ways and devices to get you there.  

I agree that any variation of a wet-bulb test combined with a quality hygrometer that can be calibrated and that's all any of us should ever need to know fairly precisely what the RH is at any given time.

Here's some pics for you:

[Robert McCollam]

In the winter, my basement shop is dry 25 -35 RH is this a good or bad environment for assembling instruments.

[onewent]

Steve .. Hesh's info is spot-on.  You need to get a sling psychrometer.  I've used one for years to calibrate my hygrometers.  No matter how expensive or technologically advanced your hygrometer is, it's not a help to you if not accurately calibrated with a wet/dry system like a sling psychrometer.  Tom

[eliya]

Has anyone tried measuring humidity with two meat thermometers? I'm asking because they're sturdier than other thermometers, easier to store, and seem to be able to measure ambient temperature. They're probably not incredibly accurate for ambient temp, but if they both have the same error, then I should be fine. No?