I have seen a few moisture detectors for lumber and was curious if I
could use an ohm-meter to do the same? Do commercial made moisture
meters have a selector switch for various wood species?
Are there tables for interpreting the conductivity of one wood specie
to another? (Or do I only need to standardize my ohm-meter to a
"known" dry sample before I use it to test the lumber I plan to use?)
Thanks in advance to those who reply(seriously or silly).
Marc

"marc rosen" wrote in message
oups.com...
I have seen a few moisture detectors for lumber and was curious if I
could use an ohm-meter to do the same? Do commercial made moisture
meters have a selector switch for various wood species?
Are there tables for interpreting the conductivity of one wood specie
to another? (Or do I only need to standardize my ohm-meter to a
"known" dry sample before I use it to test the lumber I plan to use?)
Thanks in advance to those who reply(seriously or silly).
Marc

Lots of resistance in wood, but yes, you can calibrate a megaohm range meter
to read what is there.

http://www.fpl.fs.fed.us/documnts/pdf1994/james94a.pdf
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr06.pdf

In article , "George" george@least wrote:

"marc rosen" wrote in message
roups.com...
I have seen a few moisture detectors for lumber and was curious if I
could use an ohm-meter to do the same? Do commercial made moisture
meters have a selector switch for various wood species?
Are there tables for interpreting the conductivity of one wood specie
to another? (Or do I only need to standardize my ohm-meter to a
"known" dry sample before I use it to test the lumber I plan to use?)
Thanks in advance to those who reply(seriously or silly).
Marc

Lots of resistance in wood, but yes, you can calibrate a megaohm range meter
to read what is there.

http://www.fpl.fs.fed.us/documnts/pdf1994/james94a.pdf
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr06.pdf

Waaaaay cool. Thanks for posting those links, George.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

Pin meters are a big disappointment. The problem is that you really
have to measure conductance, not conductivity, and that needs a
consistent arrangement of electrodes in the timber, not just a surface
contact. The only way to get any really useful measurements from one
are to use big pins and a slide-hammer to sink them repeatedly each
time. With that and a few bucks worth of electronic front-end meter,
then you're set. An FET front-end and moving-needle meter is easier to
stick a calibration scale to than a digital meter.

If you want rapid NDT measurement, go for a loss factor bridge (still
fairly easy to build, if you understand electronics at the "amateur
radio" level).

On the whole though, measure air humidity and allow time for your
timber to equilibriate. It's much more accurate (and useful) unless you
expend serious effort on your moisture meter.