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All this talk of relative humidty
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Author:  Lillian F-W [ Sun Oct 07, 2007 6:22 am ]
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Fall has arrived with a vengeance here in the Pacific Northwest. I know I can't do anything out in the garage until next summer. Except the big tool stuff. Its unheated. So I've started to ooze my way into building in the house. Most move slowly so as not to get an immediate "No".   

After all the recent talk about relative humidity and problems caused by not paying attention to it, I thought it would be best to pick up a hydrometer to get an idea of where things are. Was I surprised. I knew it would be a bit high. Its been raining (read misting, drizzling, light rain. It rarely rains here the way it does back East) and we haven't started using the fireplace, but I never expected it to be 90-93%. I am so glad I bothered to look. That would have been a guarantee of failure. I know I'm going to encounter a multitude of problems through out this build without creating more for myself.

So thanks. Message heard and appreciated.
Author:  Allen McFarlen [ Sun Oct 07, 2007 7:11 am ]
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I just purchased a dehumidifier last weekend and installed it in a spare bedroom. The temperature stays a pretty constant 28-32 here all year round. What changes is the humidity.

Our homes are pretty wide open to let breezes through and the humidity at the moment has been a relatively dry 60%. I closed up the bedroom and turned on the dehumidifier. I was pleased to see that after running for 6 hours the humidity had dropped to 40% and 32 degrees. What really shocked me was to find nearly 8 litres of water in the dehumidifier tank. I let it run over night and found about 6 more litres.

It sure does make using HHG easy in there though. Very hot and no drafts. I'm almost thinking that I can attempt using HHG for the gluing the top and back plates to the rims.
Author:  Bruce Dickey [ Sun Oct 07, 2007 8:56 am ]
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Now you got me wondering Terry.....

I've had a digital, well two, one for the garage, I don't spray at over 50%. Then in the shop which has AC and Heat, and it stays at 45% digitally speaking. Hmmmm.

What is a sling hygrometer?

Author:  Bruce Dickey [ Sun Oct 07, 2007 8:59 am ]
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Found this on Ebay, how does it work?
Author:  Lillian F-W [ Sun Oct 07, 2007 10:35 am ]
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Sling hydrometer, psychrometer This is best explanation I could find.
Author:  Bruce Dickey [ Sun Oct 07, 2007 1:33 pm ]
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Pretty simple.
Author:  John Lewis [ Sun Oct 07, 2007 1:55 pm ]
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[QUOTE=terken] I was using the $20 digital hygrometers the last few years and was happy as
a clam. Recently, stimulated by discussions here I got a sling hygrometer on
Ebay and later an Abbeon. (They both read the same) I found my digital
ones were all reading at least 10 % points low. I was probably running my
shop around 55%. Now when the big boys say 45% the digitals are around
32%.
The sling hygrometer was cheap, agrees with the Abbeon, and that's what I
go by now.
Terry[/QUOTE]

That's weird, the same thing happened to me too. I bought 2 digital Caliber III hygrometers from eBay and they read about 40-45% in the house and the Taylor sling psychrometer I bought at the same time reads about 8-9% higher. I thought the Taylor was not right until I bought a couple of Abbeons that agree with the Taylor. Right now the Abbeons say 54% and 55% and both digitals read 46%.

I guess with hygrometers you get what you pay for. My small digitals work well enough to stick in a cigar humidor - not for lutherie. They have a "satisfaction guaranteed" sticker on the box and say they are accurate to +/- 1% RH, so I may see about exchanging these for ones that work. The sling psychrometer is worth buying to calibrate the hygrometers for sure.
Author:  Jim Watts [ Sun Oct 07, 2007 3:32 pm ]
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I have an environmental chamber in my lab at the day job and tossed in my cheap digital during some runs at few know rh values and found my hygrometer read 7-8% low also in the ranges I'd expect to see.
Author:  crazymanmichael [ Mon Oct 08, 2007 3:25 am ]
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i too have several digitals, including a couple el cheapos from walmart. my psychrometre is a bit older than the one shown above but they don't wear out, though you may need to change the wick from time to time if you use tap water.

my digitals have always come in +/- 3* compared to the psychrometre. i check the digitals every few months, usually around the change of season.
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