First, I don't own a moisture meter (haven't justified the purchase
yet). I was wandering, if my house is mainatained at 40% humidity, and
my garage is at from 50-60% humidity, how do I know when my bowls are
dry enough to finish? If I finish the bowls that have reached
equilibrium in my garage, they warp when I take them into the house. I
recently converted a refrigerator into a kiln and I'm measuring the
humidity in the refrigerator to try to establish a point at which I
think the bowls are dry. If I dry them to 40% humidity, shouldn't that
stop most of the movement I get when I take them into the house?
The kiln appears to be working well. No cracks. Humidity has dropped
from 85% to 70% since March 10 (this might be a little fast). I'm
using light bulbs on a thermostat to control the heat. Humidity is
being controlled via vents in the refrigerator (still learning how to
adjust these). I've tried to search the web for some information about
how long, how hot, how much ventilation, etc. I'm finding a mixed bag
of information (most are dealing with large commercial type kilns).
Any information you might provide would be appreciated.

Thanks,
JD

On Mar 16, 11:47 am, "JD" wrote:
First, I don't own a moisture meter (haven't justified the purchase
yet). I was wandering, if my house is mainatained at 40% humidity, and
my garage is at from 50-60% humidity, how do I know when my bowls are
dry enough to finish? If I finish the bowls that have reached
equilibrium in my garage, they warp when I take them into the house. I
recently converted a refrigerator into a kiln and I'm measuring the
humidity in the refrigerator to try to establish a point at which I
think the bowls are dry. If I dry them to 40% humidity, shouldn't that
stop most of the movement I get when I take them into the house?
The kiln appears to be working well. No cracks. Humidity has dropped
from 85% to 70% since March 10 (this might be a little fast). I'm
using light bulbs on a thermostat to control the heat. Humidity is
being controlled via vents in the refrigerator (still learning how to
adjust these). I've tried to search the web for some information about
how long, how hot, how much ventilation, etc. I'm finding a mixed bag
of information (most are dealing with large commercial type kilns).
Any information you might provide would be appreciated.

Thanks,
JD

I don't own a moisture meter either. I believe what you are looking
for is an average between 6% to 12% moisture content but without a
meter, you'll never know! I usually use the weighing method. I rough
turn my bowls and let them dry either on a shelf or in a paper bag if
I want to slow down the drying process a bit to minimize cracking.
After a few weeks, I weigh the piece and record the date and weight.
Back it goes on the shelf and I do it again after a few days and
record the changes. Depending on the size, shape, thickness, etc,
after a while, the weight stays the same. I then leave it for a few
days more and weigh it again. If there has been no change within a
month, I consider the wood to have reached an equilibrium and THAT is
what I am looking for. Numbers are great but they are all relative
which is why nobody can place a specific value on the dryness
required, they are all margins between this and that, based on species
and whether you live in the rain forest or not!

As to your refrigerator, any enclosure will work to dry wood providing
you can control ambiant temperature and proper air circulation. A
fridge is kind of small so if you are using a bulb to provide the
heat, a small wattage is probably what you want. Either way, fridge or
no fridge, a scale will tell you all you need to know.

When you have a moment to peruse the 2000+ replies, do a search for
"dry wood" on this site. There's some really good stuff in there from
people that are way more knowledgeable than I am.

Works for me.

Mike Courteau

http://www.toymakersite.com

"JD" wrote in message
oups.com...
First, I don't own a moisture meter (haven't justified the purchase
yet). I was wandering, if my house is mainatained at 40% humidity, and
my garage is at from 50-60% humidity, how do I know when my bowls are
dry enough to finish? If I finish the bowls that have reached
equilibrium in my garage, they warp when I take them into the house. I
recently converted a refrigerator into a kiln and I'm measuring the
humidity in the refrigerator to try to establish a point at which I
think the bowls are dry. If I dry them to 40% humidity, shouldn't that
stop most of the movement I get when I take them into the house?
The kiln appears to be working well. No cracks. Humidity has dropped
from 85% to 70% since March 10 (this might be a little fast). I'm
using light bulbs on a thermostat to control the heat. Humidity is
being controlled via vents in the refrigerator (still learning how to
adjust these). I've tried to search the web for some information about
how long, how hot, how much ventilation, etc. I'm finding a mixed bag
of information (most are dealing with large commercial type kilns).
Any information you might provide would be appreciated.


Wood is dry relatively - depending on relative humidity of the environment.
Wood loses and gains bulk with moisture loss and gain, so it'll always move.
The wood can take a "set" if you overdry it, so if you're up to the risk,
you can do that, and minimize subsequent range of movement.

If you have a hygrometer, and they're cheap, you can monitor the RH and use
the tables in
http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm chapter
three to see what the moisture content by weight really is. Equilibrium is
indicated by no weight change, but also depends on no change in the RH.
While you're reading, take a look at the average shrinkage values for the
various species of wood. It's a good indicator of when you need to take the
first weight. You can also use them to cut your time to equilibrium by
gaming the grain and contour and how thin you cut, as long as you're pretty
satisfied with the shape you've given to the rough piece. One piece of
information to keep in mind is that the tables are based on shrinkage from
the FSP of about 30% moisture to oven dry, or zero. You'll get about two
thirds the average figures on most configurations, because you're only going
to around 10%.

Note another reality, which is that wood contracts on itself, so cutting
with a broad bottom and nearly vertical sides will give you more shrink, and
more shrink stress than cutting with a narrower bottom and sloped sides.

Adding heat in a closed, or nearly closed environment will effectively lower
the relative humidity, because warm air can carry more volume of water. It
will also energize the process of unbonding, the release of water held by
hydrogen bonds to the wood itself. If you're going to use heat and
enclosure, I suggest that you spin things up to eject as much unbound water
as possible centrifugally, and even blow compressed air through to eject
more. This will get you to and through the FSP more rapidly, because the
minimum ventilation won't have to dilute and carry away so much water.

JD wrote:
First, I don't own a moisture meter (haven't justified the purchase
yet). I was wandering, if my house is mainatained at 40% humidity, and
my garage is at from 50-60% humidity, how do I know when my bowls are
dry enough to finish? If I finish the bowls that have reached
equilibrium in my garage, they warp when I take them into the house. I
recently converted a refrigerator into a kiln and I'm measuring the
humidity in the refrigerator to try to establish a point at which I
think the bowls are dry. If I dry them to 40% humidity, shouldn't that
stop most of the movement I get when I take them into the house?
The kiln appears to be working well. No cracks. Humidity has dropped
from 85% to 70% since March 10 (this might be a little fast). I'm
using light bulbs on a thermostat to control the heat. Humidity is
being controlled via vents in the refrigerator (still learning how to
adjust these). I've tried to search the web for some information about
how long, how hot, how much ventilation, etc. I'm finding a mixed bag
of information (most are dealing with large commercial type kilns).
Any information you might provide would be appreciated.

See http://www.alaska.net/~atftb/moisture.htm, and download the Excel
spreadsheet on that page. It'll help you determine the target temp and
humidity level to get your wood to a given EMC point.

HTH...

....Kevin
--
Kevin Miller
http://www.alaska.net/~atftb
Juneau, Alaska
Registered Linux User No: 307357

JD
I just take the "more is better" approach to the issue, which is another way
of saying I prefer to rough a bowl rather than finish turn. So I have a
stack of stuff that is every where from a couple of months to a few years
old on the drying stacks. By the time I get around to finish turning a bowl
blank, I has been on the shelf for at least a year so I figure it is as dry
as it will get. For a hobby turner like me, a hundred bowls or so ahead will
make sure I have a dry blank or three just waiting.

--
God bless and safe turning
Darrell Feltmate
Truro, NS Canada
www.aroundthewoods.com

"Kevin Miller" wrote in message
...
JD wrote:
First, I don't own a moisture meter (haven't justified the purchase
yet). I was wandering, if my house is mainatained at 40% humidity, and
my garage is at from 50-60% humidity, how do I know when my bowls are
dry enough to finish? If I finish the bowls that have reached
equilibrium in my garage, they warp when I take them into the house. I
recently converted a refrigerator into a kiln and I'm measuring the
humidity in the refrigerator to try to establish a point at which I
think the bowls are dry. If I dry them to 40% humidity, shouldn't that
stop most of the movement I get when I take them into the house?
The kiln appears to be working well. No cracks. Humidity has dropped
from 85% to 70% since March 10 (this might be a little fast). I'm
using light bulbs on a thermostat to control the heat. Humidity is
being controlled via vents in the refrigerator (still learning how to
adjust these). I've tried to search the web for some information about
how long, how hot, how much ventilation, etc. I'm finding a mixed bag
of information (most are dealing with large commercial type kilns).
Any information you might provide would be appreciated.

See http://www.alaska.net/~atftb/moisture.htm, and download the Excel
spreadsheet on that page. It'll help you determine the target temp and
humidity level to get your wood to a given EMC point.

HTH...

...Kevin
--
Kevin Miller
http://www.alaska.net/~atftb
Juneau, Alaska
Registered Linux User No: 307357

In article .com,
"JD" wrote:

First, I don't own a moisture meter (haven't justified the purchase
yet).

I got the following,
http://www.harborfreight.com/cpi/cta...temnumber=2757
testing suggests it is easily worth the money

--
--------------------------------------------------------
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

Hi JD

No moisture meter here either, I'm just not interested to see how
quickly I can get dry cracked and split turnings, just for trying to
speed the drying up.

My biggest concern is to keep whole what I just made, and that
involves more the slowing down of the drying rather than speeding it
up, especially in the initial first few weeks, after that I just let
it dry out in my cabin or in the shop, I trust my feeling of the wood,
if it is dry or not.

Also, unless it is a lidded box, the little changing of the shape of a
bowl does hardly ever matter if even at all visible.

Not only that, but it will change shape as air moisture changes in its
environment, over the course of its life.

Enjoy the turning of the wood and don't be so much in a rush to get it
done, slow down, things do need time to get done right.

http://homepage.mac.com/l.vanderloo/PhotoAlbum26.html


Have fun and take care
Leo Van Der Loo

On Mar 16, 11:47 am, "JD" wrote:
First, I don't own a moisture meter (haven't justified the purchase
yet). I was wandering, if my house is mainatained at 40% humidity, and
my garage is at from 50-60% humidity, how do I know when my bowls are
dry enough to finish? If I finish the bowls that have reached
equilibrium in my garage, they warp when I take them into the house. I
recently converted a refrigerator into a kiln and I'm measuring the
humidity in the refrigerator to try to establish a point at which I
think the bowls are dry. If I dry them to 40% humidity, shouldn't that
stop most of the movement I get when I take them into the house?
The kiln appears to be working well. No cracks. Humidity has dropped
from 85% to 70% since March 10 (this might be a little fast). I'm
using light bulbs on a thermostat to control the heat. Humidity is
being controlled via vents in the refrigerator (still learning how to
adjust these). I've tried to search the web for some information about
how long, how hot, how much ventilation, etc. I'm finding a mixed bag
of information (most are dealing with large commercial type kilns).
Any information you might provide would be appreciated.

Thanks,
JD