moisture meter problem

[sparkus88]

Hi I bought a cheap moisture meter off ebay put when I tried in some wood it said 0% so I thought it was broke and returned it and bought a different one this one says 1%. Both of them had measuring ranges of 5-60% so I'm wondering if the wood is maybe just below 5% and thats why is reading 0-1%?

Mark

 

[CHJ]

What does it read if you place the probes across a dry finger? 18-20% maybe?

 

[sparkus88]

yeah around 20%

 

[marcros]

it is possible that the exposed surface itself is very low in moisture, ie below 5%. If it is similar to the cheap metre that I got from somewhere, it is probably measuring the moisture on the timber rather than in it, and is of questionable accuracy.

 

[CHJ]

yeah around 20%

Drill two small holes to match probe spacing in a scrap area as deep as your probes will reach, see what reading you get.
Or slice 50mm of the end off a length and see what reading you get.

 

[sparkus88]

I will try drilling holes tomorrow. I'm not expecting perfect accuracy just an idea.

 

[Harbo]

I have a cheap Axminster one that I use mainly as a guide as to when the timber has stopped drying out. I tend to buy timber from a local mill and store it for a few years.

Rod

 

[CHJ]

Can't expect absolute accuracy from the cheaper units, in fact I think it would be very much of a dark art to try and determine the true content throughout a substantial block of wood that had been home dried with any system, but I find the one I have very reliable for giving me an indication as to when it's safe to start turning and even when it's safe to move into a drier area without risk of undue splitting.

Even then it is more of a feel for the particular species, I can only conclude is based on passed experiences but I would be pushed to write a rough guide let alone a definitive one as to why I feel or find it safe to work a piece at a particular level.

Often if turning thin the action of cutting and finishing disperses a considerable amount of the residual moisture.

 

[jimi43]

Even with my Protimeter one only gets and estimated "absolute" reading and I do tend to use it for relative moisture content and drying progression and cessation also.

One thing that I made a mistake with early on in my understanding (basically until I read the handbook ), was to put the probes into the wood on the end grain rather than the long grain. You have to push the probes into the long grain for the reading to be "right" like this...

...makes sense when you think about it but some may not know this.

Also...as Chas points out...the reading varies with species groups..mine is calibrated for these groups and others are in a table published on the website...

Cheers

Jim