OT: Wood Moisture Measurement

sczot

Member
Join Date
Nov 2017
Location
cz
Posts
79
hello all,


we have little side project cooperating with local University. They are reading resistence between two screws screwed into wood (cca 2cm away - less then one inch)
they want us to read and log values from like ten of this devices, which is easy.
Problem is they have no interest in values of resistnance, they want us to recalculate the values to moisture value.


however i have no luck in finding some tables with values for different wood types, and from what ive read on internet, values also changes depending on temperature. Whole wood moisture measurement looks like alchemy to me right now.



Is there try&fail cycle you have to go through while tunning, or is there somewhere to start from?


Obviously this is absolute uknown area for us (automotive based factory) we have just some friendly connection to Uni, so they asked for help.


Thank you in advance for any help.
 
Look for wood moisture testers, they require no screws.
the instrument probes are at a specified distance and it calculates the moisture content. It's been too long since I worked there and I cannot remember the brand name.

james
 
the problem is that measuring equipment is given (KTY 81-210 for temperature, and uknown measuring tool for resistance between screws - they will borrow it to us, but now we dont know it) :/ we can use datalogging part of our choice
 
Why? The university should be doing the research, not you

I worked on a project like this 38 years ago for Weyerhaeuser which is a major manufacturer of wood products and has lots of tree farms.

Weyerhaeuser did the research and provided the formulas for conversion.

The moisture detector should be non-contact. Back in the dark ages we used capacitance. The conversion from capacitance to moisture varied by specie of wood too.

I see these a saw dust festivals ( lumber shows ) all the time.

Why re-invent the wheel?
 
You're not going to like this option, but my final project out of University was actually measure humidity in cork, more specifically cork stoppers.

Some of the values were possible to decipher using a lab precision decade resistance box that we got to use as a favour for the company I worked with and the last bit of the range was done with access to a proper chem lab.

We got a bunch of samples with different humidities. Measured the resistance with our device in several points and the lab technician cut it up in bits, labelled them, weighed them, put them in a drying oven, weighed them again and gave us the humidity value to match our resistance reading.
 

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