Slabs/Moisture Meter

[Tim M Tuttle]

Hey all,

I have some walnut slabs I've been drying for a little over a year. I bought a Lignomat Mini Ligno and from what I've read it seems those are only good for up to 5/4 stock. After some more research, the Lignomat SD looks to be quite a bit better meter (and more expensive). What do you all recommend for metering bigger stock like my 8/4 slabs?

Thanks

[John Kee]

Measure the slabs from both sides and that should give you idea. Typically on slabs you want a core reading to tell you what's going on especially when just air drying. I went for the Wagner a few years ago and its been consistent and found discrepancies much to the chagrin of a few wood sellers trying to sell kiln dried lumber that wasn't.

[Rod Sheridan]

I use a pin type measurement.

If I'm drying slabs I drive a couple of stainless steel finishing nails halfway into the slab near the middle.

Then I hook up some small wire and bring that out of the stack.

Once a week I measure the slab and record it, once it hasn't changed in a few weeks and it's low enough I stop air drying it.......Rod.

[mark mcfarlane]

Hey all,

... I bought a Lignomat Mini Ligno ...

Thanks

Tim, in case you didn't know, mini Lignos come with 5 and 10mm pins that are stored inside the unit. You have to remove the back cover.

[Lee Schierer]

Tim, in case you didn't know, mini Lignos come with 5 and 10mm pins that are stored inside the unit. You have to remove the back cover.

You will probably need to drill small holes slightly shorter than your pins, to get the longer pins to penetrate much below the surface.

[John Kee]

What reading are you currently getting with the Lignomat?

[Kevin Jenness]

To measure mc of thick wood with a pin meter you would ideally have pins that penetrate to the core to establish the moisture gradient. Rod suggests one method to achieve that. Some meters come with a slide hammer to drive the pins to depth, some woods are too hard to drive long pins without pre-drilling. You may not want pin holes in your finished piece. Measuring mc in a thick slab with short pins is a waste of time.

With a capacitance meter like the Lignomat SD the values are dependent on the assumed specific density of the sample and the depth range of the instrument relative to the sample thickness.

What species are you drying? Thickness? Drying conditions?

A simple way to monitor drying progress without elaborate equipment is periodic weighing with a scale. When the piece stops losing weight it has achieved equilibrium with the ambient humidity.

[Tim M Tuttle]

To measure mc of thick wood with a pin meter you would ideally have pins that penetrate to the core to establish the moisture gradient. Rod suggests one method to achieve that. Some meters come with a slide hammer to drive the pins to depth, some woods are too hard to drive long pins without pre-drilling. You may not want pin holes in your finished piece. Measuring mc in a thick slab with short pins is a waste of time.

With a capacitance meter like the Lignomat SD the values are dependent on the assumed specific density of the sample and the depth range of the instrument relative to the sample thickness.

What species are you drying? Thickness? Drying conditions?

A simple way to monitor drying progress without elaborate equipment is periodic weighing with a scale. When the piece stops losing weight it has achieved equilibrium with the ambient humidity.

I am drying walnut that right now is shade over 8/4. I am drying it in my basement. I used the small pins on my mini ligno and everywhere I tested showed 6% which is the lowest the meter goes. I dont really want to put holes in my wood so I am wondering if upgrading to the SD would be a better option.

[Tim M Tuttle]

What reading are you currently getting with the Lignomat?

6% with the small pins (that's the lowest reading it is able to give).

[Lee Schierer]

Another way to get a core reading is to slice off a piece from one end equivalent to half the thickness or more and then measure the center from the end.

[peter gagliardi]

Delmhorst J2000 with the auxiliary insulated 1 to 1 1/2” pins and slide hammer has been in my toolkit for my dry kiln for almost 20 years.

[Scott T Smith]

I use either Delmhorst with a slide hammer or a Merlin deep reading pinless meter. Both work great.

[Kevin Jenness]

I used the small pins on my mini ligno and everywhere I tested showed 6% which is the lowest the meter goes. I dont really want to put holes in my wood so I am wondering if upgrading to the SD would be a better option.

The measurements you are getting now say nothing about the core mc or moisture gradient. A capacitance meter will give you an average reading if it measures deep enough. It appears that the Lignomat SD measures to a depth of 3/4" which would not give you a core reading on 8/4. Like Scott and Peter I use a Delmhorst with a slide hammer, but it does scar the wood. If you can easily weigh one of the slabs periodically that is the lowest tech, no cost non-destructive testing I know of and accurate as well.

http://www.lignomatusa.com/meters/ligno-scanner-sd-dual-depth-moisture-meter/