wet bulb woes

[peachychick]

We were gifted with an older model gqf cabinet hatcher. It has the solid door and there's no time to get the acrylic before we'll need to use it for our next hatch. I'd like to figure out how to use the wet bulb located on the side below the thermometer. I know I need a wick or shoestring on the inside connected to the humidity pan. I have the instructions off GQF's site but don't understand the conversion chart.
We are hatching Marans and have basically had best luck dryhatching since last summer. Normally we try to keep it between 70-75%humidity at hatch. Can someone tell me what this would read on the wet bulb? Or explain what the numbers on the GQF chart mean?
Any help is greatly appreciated,
Kelli

 

[patandchickens]

Stromberg's hatching book says that 50-55% r.h. is 83-87 F wet-bulb temp, at 99.5.... or for 65%, wet bulb temp is 89-90 F.

For more info, http://en.wikipedia.org/wiki/Psychrometrics#Psychrometric_chart gives you a chart (click to enlarge) to look it up on.

Make sure you use distilled water for the wet-bulb wick, and use only a reasonably clean (not old and crusty) wick.

Good luck, have fun,

Pat