Firewood moisture meters, and "wet basis" vs "dry basis"

[Stere]

My moiture meter was a £6.99 one off ebay.

 

Would be interesting to see the difference between its readings and the expensive ones.

 

Expensive ones have an inbuilt program for different wood species.

 

Extech MO230 Pocket Pin Moisture Psychrometer, Wood /Building Materials from Cole-Parmer United Kingdom

WWW.COLEPARMER.CO.UK

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Buy Extech MO230 Pocket Pin Moisture Psychrometer, Wood /Building Materials and more from our comprehensive...

 

Quote

Memory contains 3 wood groups and 4 building material groups with calibrations for approximately 150 species of wood and 19 building material types. Simultaneous digital readout of moisture content plus ambient temperature or humidity with analog bargraph display of moisture, Max moisture values, and programmable wet/dry indication Index Mode with programmable high and low values can be used to quickly locate moisture with comparative measurement 

Edited February 12, 2021 by Stere

[arboriculturist]

4 hours ago, Stere said:

My moiture meter was a £6.99 one off ebay.

 

Would be interesting to see the difference between its readings and the expensive ones.

 

Expensive ones have an inbuilt program for different wood species.

 

Extech MO230 Pocket Pin Moisture Psychrometer, Wood /Building Materials from Cole-Parmer United Kingdom

WWW.COLEPARMER.CO.UK

---

Buy Extech MO230 Pocket Pin Moisture Psychrometer, Wood /Building Materials and more from our comprehensive...

 

Still measures on 'Dry basis' though.

[Woodworks]

15 hours ago, carbs for arbs said:

 

 

I have been wondering whether a table exists that shows different species of wood and what adjustments to make to the reading for what species is being tested.   Does anyone know of such a table?  I guess it would be quite useless if you don't know what type of wood the meter is set-up/calibrated to in the first place, but it would be interesting to see nonetheless...  

 

 

There is a table in this link which my old Protimeter came with http://www.damp-meter-direct.co.uk/PDF/Articles/Wood-Calibration-Chart.pdf

 

[carbs for arbs]

Thanks @Woodworks - that's very helpful

[carbs for arbs]

I'm curious to hear people's thoughts on how much temperature plays a part, but I'm going to start a new thread on that otherwise it might get a bit buried in here and would need four pages of reading for anyone to get to it!  Hope that's within forum etiquette...  

 

Cheers

 

[daltontrees]

I have just read the whole thread and am none the wiser. No-one has explained what the difference is between wet and dry basis. Can someone spell it out please?

[Rough Hewn]

I have just read the whole thread and am none the wiser. No-one has explained what the difference is between wet and dry basis. Can someone spell it out please?

Same.
🤣[emoji106]

[Paul in the woods]

20 minutes ago, daltontrees said:

I have just read the whole thread and am none the wiser. No-one has explained what the difference is between wet and dry basis. Can someone spell it out please?

Wet basis is a measure of the water in a log, expressed as the weight of water as a percentage of the wet/unseasoned log. (i.e. wood and water)

 

Dry basis is a measure of the water in a log, expressed as the weight of water as a percentage of the completely dry log. (i.e. just the wood).

 

It gets confusing because firewood is measured on wet basis but timber for construction on dry basis.

 

Most, if not all, cheap meters seem to measure dry basis but they don't state this.

 

It is important due to the new firewood rules which somewhat strangely don't mention what basis they use but it appears to be wet basis.

 

Logs need to be 20% wet basis or under. 20% wet basis = 25% dry basis.

 

This becomes important as it seems you can air dry logs down to about 20% wet basis. If someone uses a cheap moisture meter they may think the logs are 25% and complain.

 

Realistically I would hope/expect some clarifications when the laws come in to force.

[Rough Hewn]

Wet basis is a measure of the water in a log, expressed as the weight of water as a percentage of the wet/unseasoned log. (i.e. wood and water)   Dry basis is a measure of the water in a log, expressed as the weight of water as a percentage of the completely dry log. (i.e. just the wood).   It gets confusing because firewood is measured on wet basis but timber for construction on dry basis.   Most, if not all, cheap meters seem to measure dry basis but they don't state this.   It is important due to the new firewood rules which somewhat strangely don't mention what basis they use but it appears to be wet basis.   Logs need to be 20% wet basis or under. 20% wet basis = 25% dry basis.   This becomes important as it seems you can air dry logs down to about 20% wet basis. If someone uses a cheap moisture meter they may think the logs are 25% and complain.   Realistically I would hope/expect some clarifications when the laws come in to force.

Still don’t understand.
Examples please
[emoji106]

[Woodworks]

1 minute ago, Paul in the woods said:

Wet basis is a measure of the water in a log, expressed as the weight of water as a percentage of the wet/unseasoned log. (i.e. wood and water)

 

Dry basis is a measure of the water in a log, expressed as the weight of water as a percentage of the completely dry log. (i.e. just the wood).

 

It gets confusing because firewood is measured on wet basis but timber for construction on dry basis.

 

Most, if not all, cheap meters seem to measure dry basis but they don't state this.

 

It is important due to the new firewood rules which somewhat strangely don't mention what basis they use but it appears to be wet basis.

 

Logs need to be 20% wet basis or under. 20% wet basis = 25% dry basis.

 

This becomes important as it seems you can air dry logs down to about 20% wet basis. If someone uses a cheap moisture meter they may think the logs are 25% and complain.

 

Realistically I would hope/expect some clarifications when the laws come in to force.

Can we have that excellent explanation pinned on the firewood forum?