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Hygrometer Options
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Author:  Andy Birko [ Thu Jan 15, 2009 2:17 pm ]
Post subject:  Hygrometer Options
I'm thinking that I really do need to get my humidity under better control in my shop and was wondering about some of options out there as far as low cost hygrometers. I remember from way back that hair is very good medium to use for measuring humidity and that for years it was the gold standard for non dual bulb hygrometers. I've found these two that use synthetic hair and are pretty low cost:

http://www.partshelf.com/taylor5565.html

http://www.humidordiscount.com/Cigar-Ac ... rrency=USD

Thoughts
Author:  Hesh [ Thu Jan 15, 2009 2:29 pm ]
Post subject:  Re: Hygrometer Options
Andy bro the Taylor looks interesting and is a new one to me that I was not aware of.

The thing to know about mechanical hygrometers is that they do need to be recalibrated periodically and the accuracy +/- is calculated by whom ever does the calibration within a - specific - range. If you notice Taylor alludes to this and the other cheaper one actually indicates the range that they think that their hygrometer is accurate.

I have an Aberon and I send mine back for calibration twice a year. Aberon has two levels of calibration available with the NIST standard being $75 and a lesser standard, calibrated against their in house mule to be +/- 2.5% for about $30.

It's a hassle sending it in for calibration but Aberon is pretty fast in getting it back to me. I use two Caliber III digitals too and note how much they are off against a freshly calibrated Aberon. When the Aberon is gone the Caliber III's (which both read exactly the same as each other) are used with the noted increment.

Nothing beats a wet bulb though but who has the stinkin time to be doing that every hour of the day...... gaah

That Taylor looks good though - if they offer recalibration services I would get one of those.
Author:  Andy Birko [ Thu Jan 15, 2009 2:52 pm ]
Post subject:  Re: Hygrometer Options
As to calibration, making a psychrometer is pretty easy, they're just a pain to use. Checking every 3 months against a home made psychrometer would be one way to check if your hygrometer needs adjustment.

There is also a way to test accuracy by using the vapor pressure of a known solution to generate a RH of a known %-age in a sealed box like a big tupperware or something like that. I've seen some tutes for using salt or ethylene glycol to generate such solutions but I believe that those give an RH close to the 70 to 80% range as that's what the cigar guys use to calibrate their hygrometers. I betcha though that whatever solutions they use for those in-case humidity regulators is much closer to that 50% range and could be used to check is one's hygrometer needs to be sent out.

What are you guys thinking is the accuracy requirement for humidity in a shop and is this based on data or a gut feeling?

Edit: I also think that checking and calibrating at home would be far superior to sending out because I'd be more worried about the device going out of cal in shipping from vibration and shock that I am of it going out of calibration sitting in the shop. The Taylor blurb alludes that sitting at an extreme can throw it out of whack too and that is certainly more likely in shipping than hanging on the wall.
Author:  WaddyThomson [ Thu Jan 15, 2009 3:38 pm ]
Post subject:  Re: Hygrometer Options
Psychrometer's/wet&dry bulb thermometers, are easy to make. A couple of lab grade thermometers mounted to a board, with one bulb stuck in an old tennis shoe lace which hangs in a medicine bottle of water, and keeps it damp. Draw (not blow) air across for a couple of minutes, or until it stops changing, and read the difference, look up on a chart.

I don't know about the Taylor. It says +/- 5%, and on a 100 scale, as humidity is, you are looking at a 10% swing. That seems like a lot to me. Most all mechanical hygrometers can be calibrated in some form. some are more accurate than others. I have a cheap digital that is consistently low by about 5 - 6 points, and a mechanical that is off by about 3 points, on the high side, and one of the Caliber III's which seems to be the standard in my shop, as it is pretty close, when I do the wet/dry bulb thing.
Author:  Andy Birko [ Thu Jan 15, 2009 3:51 pm ]
Post subject:  Re: Hygrometer Options
Calibrating/testing a hygrometer using salt and water (reads 75%)

http://exoticpets.about.com/od/herpreso ... ometer.htm
Author:  WaddyThomson [ Thu Jan 15, 2009 3:55 pm ]
Post subject:  Re: Hygrometer Options
It is one way to calibrate, but it calibrates at 75%, which is 30+ points from where you need it to read accurately. That's a big difference. The Psychrometer is really the only way to do it accurately.
Author:  Andy Birko [ Thu Jan 15, 2009 4:02 pm ]
Post subject:  Re: Hygrometer Options
WaddyThomson wrote:

I don't know about the Taylor. It says +/- 5%, and on a 100 scale, as humidity is, you are looking at a 10% swing. That seems like a lot to me.


10% does seem like a lot but is it really? If you're reading 45% but it's really 40 or 50% is that a big deal when it comes to gluing braces etc? Googling quickly I found this table: http://www.canyoncreek.com/products/the ... ects_wood/

They don't have Spruce, but with Fir in a top 14" wide, a difference of humidity of 5% high would result in the "width" difference of just over 0.001". Less for the Pine (assuming I did my math right). That doesn't seem like it would change the dome very much (I'm too lazy to calculate the difference in radius but I'm sure if I looked harder I could find a web site to do it).
Author:  WaddyThomson [ Thu Jan 15, 2009 4:21 pm ]
Post subject:  Re: Hygrometer Options
The Caliber III's are guaranteed to be within =/- 1% between 20 - 99% RH. They are small, have a magnetic back on them, mount easily, and you can get them from some of the Tobacco/Cigar dealers on the internet anywhere between $15 - 20.00. I think I paid about $19.00 for mine. They are designed for humidors, so it's important for them to be accurate. No self respecting cigar aficionado would want his stash spoiled by incorrect humidity! [headinwall] [headinwall]
Author:  Hesh [ Thu Jan 15, 2009 5:04 pm ]
Post subject:  Re: Hygrometer Options
My 2 Caliber III's consistently read about about 3% less than my Aberon (again recently calibrated). But once you know the error it's easy to work with. Amazingly at least to me both of the Caliber III's always match each other in terms of the reading.

I think that it's a great product, inexpensive, available, small, etc. They are certainly better than nothing and the best digitals that I have used. Thanks again to Tracy for turning me on to these. [:Y:] [clap] [clap] [clap]

BTW the Caliber III's come with an instruction sheet that specifically warns against doing the salt calibration.
Author:  Alan [ Thu Jan 15, 2009 6:27 pm ]
Post subject:  Re: Hygrometer Options
I bought a B&K Percision model 625 Thermo Hygrometer and a Caliber III. Someone had told me that the B&K had been recommended by a person they knew at NOAA as being fairly inexpensive and accurate for measuring RH. I have compared the reading of the Caliber III several times with the B&K Percision unit it and the Caliber IIII has been within 2% or 3%. This is much better than the other digital that I had...it was off by about 15% off.
Author:  Alexandru Marian [ Thu Jan 15, 2009 6:45 pm ]
Post subject:  Re: Hygrometer Options
Hesh, it's Abbeon not Aberon beehive
Author:  Hesh [ Thu Jan 15, 2009 7:00 pm ]
Post subject:  Re: Hygrometer Options
Alexandru Marian wrote:
Hesh, it's Abbeon not Aberon beehive


Yeah it is! :o :D I just looked Alex bro and you are right! [:Y:] [clap] [clap] [clap]

I need to learn to pay better atttention.......... :D
Author:  Alan [ Thu Jan 15, 2009 7:42 pm ]
Post subject:  Re: Hygrometer Options
WaddyThomson wrote:

I don't know about the Taylor. It says +/- 5%, and on a 100 scale, as humidity is, you are looking at a 10% swing. That seems like a lot to me.



That's not quite as good as the Abbeon. The specs I've seen on them is +/- 3%.
Author:  rich altieri [ Thu Jan 15, 2009 10:54 pm ]
Post subject:  Re: Hygrometer Options
Hey Guys

Are the Caliber III models you are discussing digital? Looked on Amazon and thats all they show. I was under the impression these were small mechanical models for humidors.
Author:  WaddyThomson [ Thu Jan 15, 2009 11:15 pm ]
Post subject:  Re: Hygrometer Options
Yeah, they are all digital, and small. Designed to fit in a humidor. They will also fit nicely in a guitar case if you want to put one there.
Author:  Lillian F-W [ Fri Jan 16, 2009 7:59 am ]
Post subject:  Re: Hygrometer Options
I have a Caliber III, digital. It was the first one I picked up. I was given a clock with a hygrometer on the face as a present for the shop. There was a constant 15 point difference between the two, so I picked up a hair hydrometer off of eBay. It was about 3 points off of the clock. So... I made a sling psychrometer. The eBay model is the closest. The Caliber III runs 11 points too low.

Find JJ's thread and make a sling psychrometer. Its cheap, its easy and then you will know what's really going on in the shop.
Author:  Fred Tellier [ Fri Jan 16, 2009 5:03 pm ]
Post subject:  Re: Hygrometer Options
I had never heard of the Caliber III and looked it up on ebay its a good price.
http://cgi.ebay.com/Western-Caliber-III-Digital-Hygrometer-Thermometer_W0QQitemZ390018699820QQcmdZViewItemQQptZCollectibles_Tobacciana?hash=item390018699820&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

Fred
Author:  Alan [ Fri Jan 16, 2009 6:30 pm ]
Post subject:  Re: Hygrometer Options
Yep, that's it. I bought mine from a place that sold supplies for cigar humidors, but can't remember the name of the place. It was about the same price as the one on eBay. StewMac also sells it ($26.95).
Author:  Andy Birko [ Fri Jan 16, 2009 7:38 pm ]
Post subject:  Re: Hygrometer Options
Fred Tellier wrote:
I had never heard of the Caliber III and looked it up on ebay its a good price.
http://cgi.ebay.com/Western-Caliber-III-Digital-Hygrometer-Thermometer_W0QQitemZ390018699820QQcmdZViewItemQQptZCollectibles_Tobacciana?hash=item390018699820&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

Fred


Done.


Thanks.
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