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wood moisture content

updated sun 26 sep 99

 

jim behan on wed 22 sep 99

What is meant by dry wood? Do any woodfirers measure
the moisture content of their wood or do they judge
'by eye'? Is there a benchmark? I've just had a
forgetable firing and feel I need more precision in
this area. Comments please.

===
>From : Jim Behan (Dolmen Pottery) 113, Green Rd., Carlow Ireland. e-mail dolmenp
website http://members.tripod.co.uk/jimbehan/index.html
__________________________________________________
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gari whelon on thu 23 sep 99

Hi Jim

I'm no expert so take my opinion for what its worth.

I've been firing the Tozan kilns for 4 or 5 years now and we have had
problems with wet wood at times.

I know of no scientific way to measure moisture.

We use a touch and judge method.

By holding split wood to your bare cheek, you can feel the difference
between high versus low moisture I believe. The wetter will either feel
damper or colder than the dry wood.

I'll be interested in seeing what other responses and suggestions you
receive. If you get private responses please share them.

Thanx

Gari Whelon
Nanaimo B.C.


At 02:19 PM 9/22/1999 EDT, jim behan wrote:
>----------------------------Original message----------------------------
>What is meant by dry wood? Do any woodfirers measure
>the moisture content of their wood or do they judge
>'by eye'? Is there a benchmark? I've just had a
>forgetable firing and feel I need more precision in
>this area. Comments please.
>
>===
>>From : Jim Behan (Dolmen Pottery) 113, Green Rd., Carlow Ireland. e-mail
dolmenp
>website http://members.tripod.co.uk/jimbehan/index.html
>__________________________________________________
>Do You Yahoo!?
>Bid and sell for free at http://auctions.yahoo.com
>
>

Charlie and Linda on fri 24 sep 99

> I know of no scientific way to measure moisture.
>
> We use a touch and judge method.
>
> By holding split wood to your bare cheek, you can feel the difference
> between high versus low moisture I believe. The wetter will either feel


There is an electronic hand held meter that has two prongs the you press
into wood and it will read out the moisture content. Works like a
voltmeter/circuit tester. The kiln dried red oak furnature factory
where I get our wood from has one. The owner was able to give me a read
out in 5 secs. Pretty nice but maybe too high tec for the most of us.

If you want one of these devices you could check with companies that
cater to the lumber industry. If anyone is really interested let me
know and I'll run down my catalog at the "other job" and let them know.

Charlie Riggs

4 more days until we deliever a show to a gallery. You know what I mean?
Getting great "naked raku" results thanks to you all.
Thank you, thank you.

Ray Aldridge on sat 25 sep 99

At 10:49 AM 9/23/99 EDT, you wrote:
>----------------------------Original message----------------------------
>Hi Jim
>
>I'm no expert so take my opinion for what its worth.
>
>I've been firing the Tozan kilns for 4 or 5 years now and we have had
>problems with wet wood at times.
>
>I know of no scientific way to measure moisture.
>

For what it's worth, marine surveyors use a "moisture meter" to measure the
amount of water absorbed by fiberglass hulls. Off hand, I can't think of
any reason why this wouldn't work on wood, but the meter is pretty
expensive, I'm told. I don't know what principle it uses, but it's a
nondestructive test-- the meter is simply moved from one part of the hull
to another.

Ray

John Baymore on sat 25 sep 99

------------------
(clip)

What is meant by dry wood? Do any woodfirers measure the moisture content
of their wood or do they judge 'by eye'?

(snip)

Jim,

Been firing with wood since 1968-69.

Always guaged by eye, feel, smell, and of course, age since cut, although
there certainly should be a way to use weight measure per cubic foot, since
places like the various agricultural extension services have nice charts of
the average weight of a =22dry=22 cubic foot of specific species of wood.

Weigh a =22dry=22 chunk of wood of the species involved of very specific
dimensions. This must be a dry as you can get it.... heated for long
periods in a hot oven (kiln dried...in wood parlance). Weigh a target
sample of the same dimensions of the wood in question. The difference in
weight is mostly (some different growth/cell factors will make this a
little off) the water content. Convert to a percentage. You then have a
rough water content figure for your stack of wood. Find what you like for
your firings....and then you can match it pretty well.

Forrest fire type people use =22fire sticks=22 to measure general fire =
danger.
They have specific pieces of wood laying around in the woods of which they
continiously monitor the weight. The lighter they are .... the higher the
fire danger (dryer wood catches fire more easily).

For kilns, like wood stoves, the typical =22rule of thumb=22 seems to be =
about
a year old....dried under cover. But that can vary a lot depending on
things like type of wood, size the wood is cut, how stacked, how well
protected from the elements, and the climate (typical humidity) that you
are in.

Also for certain situations some wood firers like to use =22wet=22 (green) =
wood
for certain PARTS of the firing. For temperature climb to stoneware
temps.... the woods GOTTA be dry.

Also.... the more marginal the kiln design, the more sensitive it will be
to the dryness of the wood being stoked.

Some of the Japanese I talked to seem to swear by red pine, dried 1 1/2
years. Over 2 years is no good..... they say the resins dry out too much.

If you are stoking it into a firebox where you have visual access to the
wood and you are getting a lot of sap sizzling and boiling out of the end
grain parts (early stages of the firing when you can see the =22cold ends=22
for a while).... it is pretty wet. Unfortunately, the totally subjective
phrase there is =22...a lot of....=22 =3Cg=3E. What exactly does that mean?=
I'd
have to show you what I mean =3Cg=3E.

BTW.... for reference..... I currently fire a noborigama and use pine and
hemlock.


Best,

..................john

John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA

603-654-2752
JBaymore=40compuserve.com
John.Baymore=40GSD-CO.COM

Corinne P. Null on sat 25 sep 99

Our house wouldn't hold paint, so the rep from the paint company came out
with one of these pronged gizmos and stuck it in the wood all around the
house. The cedar was so soaked we ended up tearing it all off and going
with vinyl. Being purists, it was difficult to switch to, yuk, (whisper)
plastic, but now that it's done it's a relief to think we'll never have to
paint it again. Whew.

Great little device, though.

Corinne Null
Bedford, New Hampshire
null@mediaone.net


----------------------------Original message----------------------------

There is an electronic hand held meter that has two prongs the you press
into wood and it will read out the moisture content.

Charlie Riggs