Moisture Meters

[Stephen1]

Hi everyone
What Moisture Meter is everyone using?
I am ordering an IDRY kiln this week and will need a better moiture meter than the one I have. 

[WDH]

My go to meter is the Delmhorst J-2000X.  With the long insulated pins. 

[scsmith42]

My go to meter is the Delmhorst J-2000X.  With the long insulated pins.

Me too.  I have a slide hammer with it for checking thicker planks and slabs.
My favorite is a Merlin that will read about 1.5" deep.  We use it all the time.

[WDH]

I also have a pinless Wagner MMC210 that is great for 4/4.

[YellowHammer]

Delmhorst J2000 with slide hammer.  Nothing fancy, just works. 
 
Has self calibration checks, and temp and species correction.  

[Busysawyer]

I am using the delmhorst j2000 as well. I'm having a little issue getting consistent readings. I'll try to explain. When I open the kiln door to check and see if the wood is ready to come out I adjust the temp setting on the meter to 145f. The air in the kiln is about 155f so I figure the temp of the wood around 145f. I haven't played around with the temp settings much yet. What is happening is I test right after opening the door and let's say I'm seeing 5-6% on the meter. I pull the load and stack it. Come back the next day, now the wood has been sitting on the heated barn for 24 hours. I adjust the meter to read at 70f. Now the readings are all coming back at 6-7%. Not a huge difference but my next day readings have consistently been about 2% higher. This has been the same for every species and thickness.  4/4 poplar,maple,red oak,sassafras and walnut.  6/4 , 8/4 , 12/4 and 16/4 walnut and maple as well.

[YellowHammer]

How deep are you probing?  Are you taking readings at various depths?  Check the calibration shunt of the meter to make sure it is reading correctly.  If you want to see what the effect of the temperature compensation is, just take successive reading while adjusting the temp setting.  It's a simple uncertainty analysis and will give you a better feel for the meter and how the adjustments effect the reading.  Of course, the truth is revealed by oven drying, which is by far the most accurate method to determine moisture content.  

What you are describing is commonly referred to as "rebound" where the wood isn't fully equalized, it is dried too fast or not long enough, and there is a moisture gradient in the wood at various depths or locations in the wood.  When removed from the kiln, it will, by itself, diffuse moisture, higher to lower.   That's why I like to "rest" my wood in the kiln for a day, after sterilization, to prevent or reduce the rebound effect and to insure everything is right with the stack.  It's not unusual for me to rerun for a day, to bring it down a second time.  

Not the same process but I liken it to "resting" a steak after coming off the grill.

I'm not sure this is the issue as supposedly vacuum kilns are relatively immune to inadequate equalization.  Did you ever run a prong test?  

[Busysawyer]

Yh, I have not ran a prong test yet. I'm not sure what probes came with my meter but I am burying them all the way in everytime I test. I'm not sure what the calibration shunt is, could you please elaborate.  My testing procedure is very basic. Set the number to whatever the species chart says, adjust temp to either 145f or 70f, bury probes in various locations. If I'm getting the 6-7% I'm looking for I cut about 6" off a couple boards and test the cut ends. I'm thinking eventually I will skip that last step due to the fact that no matter what board or where I test I'm getting very similar and consistent readings.

[WDH]

Consistency is good.  You can deal with consistent. 

[Stephen1]

Everybody seems to like to Delmhorst. I'll put that in the Christmas wish basket!

[GeneWengert-WoodDoc]

The temperature effect on pin meters is 1% for every 20 degrees away from 70 F.  It is an approximation.  For cold wood, add to the reading, and for hot, subtract.  

You should use the kiln temperature...the spot where the tips of the pins are is not affected by opening the door or cooling.

To get the average MC, drive the pins only 20 to 25% of the thickness of the lumber.

Do not take a meter into a kiln with high or even moderate humidity...the meter will be cool and will therefore condense moisture on the hardware and even inside the cable and affect the readings. 

The hammer probe referred to is the 26-ES probe at Delmhost.

Delmhost also makes a probe shaped like a large "T" that allows moisture measurement inside a stack of lumber that is on sticks.

[Escavader]

Wagner with the wand to check inside the packs.wagner pinless handheld at the planer mill.we have darn good luck with them