Performed Moisture Content with VOM

[ColdNorCal]

Performed the moisture content per the Sticky and USFDept example using VOM. Measured Oak rounds that were cut last fall and split in April this year. They have been sitting in direct sun in the Sacramento area where temps range from 75-105 with low humidity for the past 6 months.

I split a 6-7 inch wedge in half and tried multiple times, in multiple areas, to get a reading but could not. Used new screws driven as deep as a 1/2" and as close as 3/8" apart and made sure, as best as possible, the screws were in the same grain. No reading. Infinity ohms registered even at 2,000k ohms scale.

Split a 10" round that was cut this April and sitting in the sun but not split. I measured with screws ~1" apart and 1/2" deep and measured about ~130K ohms.

The VOM is a craftsman and in very good shape with new battery. I dont have a high ohm resistor to verify the vom. I did use my body though. Resistance would fluctuate from 300-700k ohms depending on how hard I would hold the probes. This seems inline from what is on the internet.

Given all the threads and comments about how hard it is to dry oak, do these measurements seem plausible? Infinity, open circuit, resistance means extremely low moisture content?

 

[lsucet]

is good to have an alternative way of measurement but for the cost of a meter now a dates is easy to grab one and get more accurate idea of what is going on. just my opinion.

 

[begreen]

Wood dries more quickly in special conditions. And not all wood starts off with the same moisture content when green. It's possible that your local oak started off with a lower moisture content than say some white oak from a damp location back east. A Sacramento summer would be somewhat similar to a solar kiln, especially if there was good airflow through the stacks. So, it might be ok to burn, but we can't say for certain. If the wood is <20% moisture content it should burn ok. A moisture meter is cheap if you want to verify, but your testing has some validity.

We'd only be speculating on how dry the wood is, but here are some subjective tests you can do. Resplit the wood and press it up against your cheek. Damp wood will feel notably cooler than dry wood. Weight - wet wood is notably heavier, Sound - two damp splits banged together will go clunk; two dry splits banged together will produce a clear note, like klaves or two baseball bats banged together.

 

[TheAardvark]

I would just spend $20 on a moisture meter and be done with it.

 

[ColdNorCal]

Wood dries more quickly in special conditions. And not all wood starts off with the same moisture content when green. It's possible that your local oak started off with a lower moisture content than say some white oak from a damp location back east. A Sacramento summer would be somewhat similar to a solar kiln, especially if there was good airflow through the stacks. So, it might be ok to burn, but we can't say for certain. If the wood is <20% moisture content it should burn ok. A moisture meter is cheap if you want to verify, but your testing has some validity.

We'd only be speculating on how dry the wood is, but here are some subjective tests you can do. Resplit the wood and press it up against your cheek. Damp wood will feel notably cooler than dry wood. Weight - wet wood is notably heavier, Sound - two damp splits banged together will go clunk; two dry splits banged together will produce a clear note, like klaves or two baseball bats banged together.

Agreed, the findings do have some validity as the vom seemed to behave fine. The results were unexpected though given all the posts in other threads about seasoning oak.

The oak has not been stacked yet. The splits have been laid out in a large flat area, no shade, getting a suntan. Every several weeks I would turn the spits over for even sunning. lol

If money were to be spent, I'd rather spend it on something more useful like another vom, chain for saw or ?

 

[begreen]

This was discussed here about a decade ago. Scale should be at least 10M ohms. A Fluke industrial meter will read up to 50M ohms.
https://www.hearth.com/talk/threads/using-a-multimeter-to-measure-wood-moisture-level.40033/
another source using the forest service tables
https://www.instructables.com/id/Measure-the-Moisture-Content-of-Your-Firewood-With/
simple but reliable meter
(broken link removed)

 

[ColdNorCal]

Yes, that is the "sticky" I mentioned.

 

[begreen]

For proper testing the ohm range is too low, it should be at least 10,000K ohms. Still the wood may be passable, we can't tell remotely. Did it pass the other subjective tests?

 

[ColdNorCal]

The ohm range is too low, it should be at least 10,000K ohms. Still the wood may be passable, we can't tell remotely. Did you try the other subjective tests?

I just caught that... lol Given the highest value is 2,000k ohms and the vom never registered a reading, the resistance must be 2,000k ohms or higher. Which is good, I think...

I may look for another vom just out of curiosity.

Not yet.

 

[ben94122]

I think your multimeter is fine. My black oak got to 10-12% (fresh split face at room temperature, along the grain, pins fully seated). I had it split and stacked on pallets 3 rows deep in a shady but breezy spot for one California summer at 3500 feet elevation. I wouldn't be surprised if you drove enough of the water out of your wood to make it effectively non-conductive if you had it baking in the sun at sea level, turning occasionally as you describe above. Lots of the posters here are from the East coast or PNW where it rains every week or so all summer, and humidity is much higher.