moisture meter?
 

Hi Group
I want to buy a high quality moisture meter to analyze my hull. What is the
best and what should I have to pay?
Thanks
Bruce

--
Shield Finishes and Nauticoat Marine Finish Systems
www.shieldfinishes.com

"Bruce on horizon" wrote

Hi Group
I want to buy a high quality moisture meter to analyze my hull. What is
the
best and what should I have to pay?
Thanks
Bruce

A decent induction or capacitance type (pinless) meter for wood is going to
cost about $200 but they are not all that good for hull surveys. They only
give you a relative idea of where the wet spots are so even a basic model
will do.

A real surveyors type meter is going to cost about twice as much but really
only gives you a relative difference to some known dry area. Using one is
more of an art than a science.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Yup, Glen has it right - moisture meters only give a 'corelation' to
moisture saturation. With such 'ionstrumentation' there is always the
question ofr calibration, resolution and accuracy/knowledge of the
operator ..... just like AN Y other instrument.

If you have any science/engineering or 'lab' background ...
There is another means to determine moisture saturation if you have a
sensitive 'balance' scale (the type used by chemists, etc. that can
read to .0001 grams): Use a desiccant (activated alumina or silica gel
and condition it by baking for 8 hours at 350 degrees (will be at -40
degrees dewpoint), let come to repeatable weight in the balance,
determine the mass, and put it under a film envelope securely taped to
the spot that you want to investigate, let sit for several days and
measure the moisture uptake with the balance. This is a direct method
and requires little 'interpretation'.

An easier 'correlation' method would be to used a known mass of silica
gel that has a special indicating dye, condition the silica gel as
above and simply measure the time that the gel turns from blue to red.

Seems like I recall seeing pictures from some surveyor somewhere that used
infrared film. I think he put heat lamps on the boat for awhile, then took
a picture. Variations in core due to core type, structure, and water
intrusion show up then you validate with drilling or a moisture meter. It's
been awhile, so forgive me if I'm wrong, but it could be interesting to try.

Brian D



"Glenn Ashmore" wrote in message
news:_NJOd.35487$EG1.18459@lakeread04...
"Bruce on horizon" wrote

Hi Group
I want to buy a high quality moisture meter to analyze my hull. What is
the
best and what should I have to pay?
Thanks
Bruce

A decent induction or capacitance type (pinless) meter for wood is going
to
cost about $200 but they are not all that good for hull surveys. They
only
give you a relative idea of where the wet spots are so even a basic model
will do.

A real surveyors type meter is going to cost about twice as much but
really
only gives you a relative difference to some known dry area. Using one is
more of an art than a science.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com