"Calibrated" a digital hygrometer (WalMart Special)

[Junkmanme]

dragonchick,
Put 1/4 cup of water on 1/2 cup of salt (in cup). It should have the "consistency of "wet sand". Carefully place this salted cup into a ZipLock bag and also put the hygrometer in the bag (NOT in the salted cup). Seal the ZipLock bag and let sit for 12 to 24 hours. At the end of this period of time, the hygrometer should read 75%. If it is more or less than 75%, that is how much it is "OFF". My digital read 72%..........so it is low by 3%.

Later, when you use the hygrometer, you remember that it read 3% low.

The Analog hygrometer that you purchased MIGHT have an adjustment screw on the back. IF so, you can immediately ADJUST the hygrometer (carefully) to the 75% after you "test" it.

Clear as mud?

-Junkmanme-

 

[muddstopper]

Are you using actual salt (ie. sodium chloide), or light salt (ie. potassium chloride). the humdity results will differ between the two products. Potassium chloride have a lower salt index than sodiumchloride. Store bought salt can be either product, so read the lable

 

[Junkmanme]

muddstopper,

I used "common table salt" (sodium chloride w/iodine). Potassium Chloride does not seem to be available "over-the-counter" around here. (Apparently the Gubmint thinks it is some sort of "problem". Another Gubmint "control" that I resent!)

-Junkmanme-

 

[tothemoon]

I have a question about thermometers.......do they have to be vertical to work correctly? Also, I saw in some pictures that in incubators, the thermometer is laid directly on top of the eggs, would this give an accurate reading even if it is ok to keep them horizontal?

 

[Junkmanme]

It is my "impression" that most, if not all, will work just the same horizontal as vertical, but I am no "expert" on this at all !

-Junkmanme-

 

[muddstopper]

Quote:
If you go to your super market you should be able to find Morton Lite Salt. Its usually in a light blue box. This is potassium chloride. Also if you go to your local lawn and garden center, you can purchase 0/0/60 fertilizer, this too is potassium chloride.

Your choice of common table salt is the correct source, altho the iodine it contains will also cause a % or two differencial in RH. I would look for tablesalt without the Iodine and make a comparison, your original reading of a couple of %points off might be incorrect. I would be interested to see just how much of a difference the three different products would make in calibrateing your hygrometer.

Note to self,

Self, check kitchen cabinets and see what types of salt You have on hand and do experiments calibrateing hygometers next week.

 

[muddstopper]

Quote:
Your digital thermometers use resistive sensors to check temperature. Changes in temperatures are signaled by the amount of electricity that can pass thru the temperature sensitive resitive wire. You can lay one of these type thermometers up, down or sideways and they should read the same. The mercury bulb type might be slightly affected by horizonal and vertical simply because of barometric pressure, but the diference in accuracy would be so minicule that it would be hard to even measure. Unless of course your thermometer was several yards long.

 

[Junkmanme]

muddstopper,

THAT is GOOD to know (about "Morton Lite Salt"). I have been wanting to get some Potassium Chloride for a few years.

APPRECIATE the info!

-Junkmanme-

 

[walkswithdog]

Worst inaccuracy in a springfield type hygrometer was 25%. I threw that one out. Most were 2 or 3 or 5% off. That first one all but killed my first hatch when I tried to get the hatch phase humidity high enough... sigh. Since I generally dry incubate now it's not as big a deal. They pip, I add water. They hatch in the next 24 -36 hours, done. Now that it's all pretty much a given unless something goes wrong, I'm a good bit more relaxed.

PS hey Old Man - I did end up just replacing the dying cabinet/bator fan with the GQF. It really most closely met the size, CFMs and power usage I was looking for. I'm going to see if I can rehab the old one by cleaning and oiling it up properly. But given it's heading toward 80 years old, maybe that will work, maybe not. Thanks for the help from you and Chis and Mudd.

 

[dragonchick]

Quote:
The hydrometer does have a screw on the back. I will set it later this week and see how it fairs. The quarter may have been a high price to pay if it doesn't work, but at least I will know how to calibrate.