What is best for testing moisture content of wood, a two pin or a four pin
tester?

Andy.



--
Posted via a free Usenet account from http://www.teranews.com

"handy-andy"

What is best for testing moisture content of wood, a two pin or a four pin
tester?


How about no pins...

http://www.wmsconsulting.co.uk/mmc205.htm

Roy

RzB wrote:
"handy-andy"

What is best for testing moisture content of wood, a two pin or a four pin
tester?


How about no pins...

http://www.wmsconsulting.co.uk/mmc205.htm

Roy

Good grief! That's $300 for a hobbyist grade moisture meter.

No wonder the Brits are so pale ... they're being bled to death!

Bill


--
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John Lennon


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In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

On 2006-12-25 05:08:44 +0000, Bill in Detroit said:

RzB wrote:
"handy-andy"

What is best for testing moisture content of wood, a two pin or a four
pin tester?


How about no pins...

http://www.wmsconsulting.co.uk/mmc205.htm

Roy

Good grief! That's $300 for a hobbyist grade moisture meter.

No wonder the Brits are so pale ... they're being bled to death!

Bill

It seems especially expensive because of the weakness of the dollar.

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

I am guessing, but do 4-pin meters work on the same principle as those
BFI bathroom scales?
Sort of "Does my beam look big in this" affair? ;-)
--

Graham.
%Profound_observation%

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

True enough for planks. With the TDT (Turn, Dry,Turn) process, a moisture
meter is absolutely unnecessary. The meter relies on continuous long grain,
something not found in many places on a standard bowl form. The base or
"foot" is the only place I can think of.

Better to stack such things to dry, pull when you think they should be, and
then weigh them. If they weigh basically the same after a week, they're
ready to turn. It's equilibrium, not absolute numbers that count.

Absolutes aren't even that important in flat work except as trend
indications. If the hygrometer says the wood should be at equilibrium at
12%, and the meter shows 18, you need to wait. Of course you still follow
good practice in construction, building loose with dry wood, tight with wet
to accommodate seasonal changes. For me, in a heated home, that means 14%
in summer and 6% or less in winter.

In article , Ian
Stirling wrote:
A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

You mean weight loss on drying?

--
Aidan
Aberdeen, Scotland
Written at Tue, 26 Dec 2006 00:00 GMT, but posted later.

In uk.d-i-y Graham wrote:

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

I am guessing, but do 4-pin meters work on the same principle as those
BFI bathroom scales?
Sort of "Does my beam look big in this" affair? ;-)

The basic theory of the two wire probes is similar to measuring the
springyness of a spring, with two springy probes.
It's hard to measure the springyness (resistance) of the spring,
seperately from the probes, which tend to vary a great deal.

If with the four wire probes, you apply a constant tension with one set,
and then measure with the other, you can get an accurate figure.

The body fat scales use a similar sort of idea - though they are
designed to accurately -sort-of- measure the resistance of the thighs.

In article ,
Bill in Detroit wrote:

....

Good grief! That's $300 for a hobbyist grade moisture meter.

No wonder the Brits are so pale ... they're being bled to death!


Try
http://www.harborfreight.com/cpi/cta...emnumber=93300
or http://www.harborfreight.com/cpi/cta...temnumber=2757
(which is what I have, I use it to compare known "dry" with un-known)

--
--------------------------------------------------------
Personal e-mail is the n7bsn but at amsat.org
This posting address is a spam-trap and seldom read
RV and Camping FAQ can be found at
http://www.ralphandellen.us/rv

"Ian Stirling" wrote in message
...
In uk.d-i-y Graham wrote:

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

I am guessing, but do 4-pin meters work on the same principle as those
BFI bathroom scales?
Sort of "Does my beam look big in this" affair? ;-)

The basic theory of the two wire probes is similar to measuring the
springyness of a spring, with two springy probes.
It's hard to measure the springyness (resistance) of the spring,
seperately from the probes, which tend to vary a great deal.

If with the four wire probes, you apply a constant tension with one set,
and then measure with the other, you can get an accurate figure.

The body fat scales use a similar sort of idea - though they are
designed to accurately -sort-of- measure the resistance of the thighs.

A Wheatstone bridge?
--

Graham.
%Profound_observation%

In uk.d-i-y Graham wrote:

"Ian Stirling" wrote in message
...
In uk.d-i-y Graham wrote:

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

I am guessing, but do 4-pin meters work on the same principle as those
BFI bathroom scales?
Sort of "Does my beam look big in this" affair? ;-)

The basic theory of the two wire probes is similar to measuring the
springyness of a spring, with two springy probes.
It's hard to measure the springyness (resistance) of the spring,
seperately from the probes, which tend to vary a great deal.

If with the four wire probes, you apply a constant tension with one set,
and then measure with the other, you can get an accurate figure.

The body fat scales use a similar sort of idea - though they are
designed to accurately -sort-of- measure the resistance of the thighs.

A Wheatstone bridge?

No, that's somthing slightly different.
It would work if you could guarantee that the two feet pads made
identical contact, but you can't.
http://en.wikipedia.org/wiki/Four-terminal_sensing is a not very good
article on it.
http://www.allaboutcircuits.com/vol_1/chpt_8/9.html may be more
revealing.

Graham wrote:


"Ian Stirling" wrote in message
...
In uk.d-i-y Graham wrote:

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

I am guessing, but do 4-pin meters work on the same principle as those
BFI bathroom scales?
Sort of "Does my beam look big in this" affair? ;-)

The basic theory of the two wire probes is similar to measuring the
springyness of a spring, with two springy probes.
It's hard to measure the springyness (resistance) of the spring,
seperately from the probes, which tend to vary a great deal.

If with the four wire probes, you apply a constant tension with one set,
and then measure with the other, you can get an accurate figure.

The body fat scales use a similar sort of idea - though they are
designed to accurately -sort-of- measure the resistance of the thighs.

A Wheatstone bridge?


Works for me - actually a resister,two small alligator clips, two brads, a
bit of wire and a multimeter.

Deb

"Graham" wrote in message
...

"Ian Stirling" wrote in message
...
In uk.d-i-y Graham wrote:

"Ian Stirling" wrote in message
...
In uk.d-i-y handy-andy wrote:
What is best for testing moisture content of wood, a two pin or a four
pin
tester?

Four pin will give more comparable results.
Two pin is much more dependant on probe condition, and contact with the
wood, four pin - ideally - should not depend on this.

A sharp plug cutter, an oven at 100C for an hour, and a sensitive scale
is of course the best way.

I am guessing, but do 4-pin meters work on the same principle as those
BFI bathroom scales?
Sort of "Does my beam look big in this" affair? ;-)

The basic theory of the two wire probes is similar to measuring the
springyness of a spring, with two springy probes.
It's hard to measure the springyness (resistance) of the spring,
seperately from the probes, which tend to vary a great deal.

If with the four wire probes, you apply a constant tension with one set,
and then measure with the other, you can get an accurate figure.

The body fat scales use a similar sort of idea - though they are
designed to accurately -sort-of- measure the resistance of the thighs.

A Wheatstone bridge?
--

Try these for answers. www.fpl.fs.fed.us/documnts/fplgtr/fplgtr06.pdf
www.fpl.fs.fed.us/documnts/fplrn/fplrn008.pdf

Andy Hall wrote:
On 2006-12-25 05:08:44 +0000, Bill in Detroit said:

RzB wrote:
"handy-andy"

What is best for testing moisture content of wood, a two pin or a
four pin tester?


How about no pins...

http://www.wmsconsulting.co.uk/mmc205.htm

Roy

Good grief! That's $300 for a hobbyist grade moisture meter.

No wonder the Brits are so pale ... they're being bled to death!

Bill

It seems especially expensive because of the weakness of the dollar.




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Even at a 1:1 ratio, it would still be expensive for hobbyist use. I'm
not going to get into a transatlantic whizzing contest, but simply note
that I got mine (2 pin hobbyist grade) for about $40 .. not even 20
pounds. The only obvious lack is that it doesn't shut itself off.

If those on the far side of the pond think that ~150 pounds is an okay
price to pay for a hobbyist grade moisture meter, then, by all means, be
my guest.

Bill
--
Make yourself an honest man, and then you may be sure that there is one
rascal less in the world.
Thomas Carlyle (1795 - 1881)


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