Hi,
I am relatively new to turning and am trying to build up a stock of wood
for bowl turning. I need some advice on how to deal with green and
semi-dry wood. Specifically:
- For bowl blanks that I purchase, I usually cut out a round piece and
seal the edges. About how would it take to dry like this? If I rough out
the bowl, would it dry faster? And should I still seal the roughed-out
bowl to prevent cracking?
- For green wood cut from downed trees, can I store it in the "half-log"
shape? How should it be sealed and stored?
- What's an acceptable moisture content for final turning?
Thanks for your help!

Hello James,

If you buy bowl blanks, cut them round and seal the edges, you can
expect it to take one year for each inch of thickness, plus one more
year for fairly thick pieces.

If you rough turn to a wall thickness of about ten percent of the
diameter; i.e., 1" wall thickness for a 10 inch bowl, they will
generally dry in about 3 to 6 months and be ready to final turn. If
you weigh them, say once a week or once a month and write down the
weight on the side of the bowl, when the weight hasn't changed from
the last weight you have reached moisture equilibram and it is time to
final turn and finish.

If you are making bowl blanks from a log that you have felled, I
recommend cutting the chunks about two inches longer than they are
wide to allow for checking in the ends. Cut out the pith and paint the
endgrain with a green wood sealer. Again, they will take about one
year per inch of thickness to dry. If you have time, rough turn them
and they will be ready to final turn in a few months.

I try to separate these pieces with little stickers of at least 1/4"
thickness. At one time, I had a supply of old laths that worked very
well. Store in a cool, dry, shady location and allow room for air
flow around the wood.

There are several other things that will help prevent cracking of
rough turned bowls: Turners Choice (CedarShield), Pentacryl, freezing,
boiling, and alcohol soaking. You can also microwave dry them if you
are in a great hurry to final turn the bowl.

Fred Holder
http://www.fholder.com

Hope this helps.

On May 15, 10:03 am, James Edward wrote:
Hi,
I am relatively new to turning and am trying to build up a stock of wood
for bowl turning. I need some advice on how to deal with green and
semi-dry wood. Specifically:
- For bowl blanks that I purchase, I usually cut out a round piece and
seal the edges. About how would it take to dry like this? If I rough out
the bowl, would it dry faster? And should I still seal the roughed-out
bowl to prevent cracking?
- For green wood cut from downed trees, can I store it in the "half-log"
shape? How should it be sealed and stored?
- What's an acceptable moisture content for final turning?
Thanks for your help!

"Fred Holder" wrote in message
oups.com...
Hello James,

If you buy bowl blanks, cut them round and seal the edges, you can
expect it to take one year for each inch of thickness, plus one more
year for fairly thick pieces.

If you rough turn to a wall thickness of about ten percent of the
diameter; i.e., 1" wall thickness for a 10 inch bowl, they will
generally dry in about 3 to 6 months and be ready to final turn. If
you weigh them, say once a week or once a month and write down the
weight on the side of the bowl, when the weight hasn't changed from
the last weight you have reached moisture equilibram and it is time to
final turn and finish.

If you cut to 10%, you will probably have a lot of restyle available. On a
heart up piece with reasonably straight grain you can cut your drying time
in half by going a bit thinner. Say your wood is cherry, with a tangential
shrink of 7%, you can certainly cut to that and have fudge room. Average
dimensional loss is less than a half an inch in a dozen down to 10%
moisture, so if you want half inch thick walls, cutting to 3/4 will do it.

Don't leave the bottom too broad, or you'll stress the end grain, possibly
splitting it open on the outside. As far as weighing, wait until you see
it's shrunk some, then weigh. Wait four-five days and weigh again. Stable
with its environment is all you need. If that's 15% where you live, it
makes little sense to heat and try to get it lower. It'll only come back.

Check out the _Wood Handbook_ at
http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm for
information on how wood dries, and what to expect in the way of shape
change.

Bulking agents can help stabilize the wood, but they won't "dry" it. That
takes dilution into the atmosphere.

For me, I like to turn green wood to final thickness, then let them
dry and warp, then sand and finish. I like the warped shapes.The down
side to warped bowls is sanding them. You need a power sander, and a
variable speed lathe, down to 50 rpm or less. They are almost
impossible to sand otherwise. Generally turn to 1/4 to 1/2 inch thick.
Dry slowly. I start out with them on the floor for several days, then
up on a shelf. Usually dry in a week or two. For tricky woods, like
fruit woods or madrone, I place them in paper bags for about a week
before putting them on the floor. A lot depends on where you are and
the relative humidity. Things dry a lot differently in Arizona than
they do here in Oregon. It may take trial and error. If it is
cracking, then you are drying too fast. If it is molding, then it is
drying too slow.
robo hippy

On May 15, 2:39 pm, "George" wrote:
"Fred Holder" wrote in message

oups.com...

Hello James,

If you buy bowl blanks, cut them round and seal the edges, you can
expect it to take one year for each inch of thickness, plus one more
year for fairly thick pieces.

If you rough turn to a wall thickness of about ten percent of the
diameter; i.e., 1" wall thickness for a 10 inch bowl, they will
generally dry in about 3 to 6 months and be ready to final turn. If
you weigh them, say once a week or once a month and write down the
weight on the side of the bowl, when the weight hasn't changed from
the last weight you have reached moisture equilibram and it is time to
final turn and finish.

If you cut to 10%, you will probably have a lot of restyle available. On a
heart up piece with reasonably straight grain you can cut your drying time
in half by going a bit thinner. Say your wood is cherry, with a tangential
shrink of 7%, you can certainly cut to that and have fudge room. Average
dimensional loss is less than a half an inch in a dozen down to 10%
moisture, so if you want half inch thick walls, cutting to 3/4 will do it.

Don't leave the bottom too broad, or you'll stress the end grain, possibly
splitting it open on the outside. As far as weighing, wait until you see
it's shrunk some, then weigh. Wait four-five days and weigh again. Stable
with its environment is all you need. If that's 15% where you live, it
makes little sense to heat and try to get it lower. It'll only come back.

Check out the _Wood Handbook_ athttp://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htmfor
information on how wood dries, and what to expect in the way of shape
change.

Bulking agents can help stabilize the wood, but they won't "dry" it. That
takes dilution into the atmosphere.

James
This might help
http://aroundthewoods.com/firewood.shtml
Any questions, just holler.
---
God bless and safe turning
Darrell Feltmate
Truro, NS
http://aroundthewoods.com
http://roundopinions.blogspot.com

"James Edward" wrote in message
...
Hi,
I am relatively new to turning and am trying to build up a stock of wood
for bowl turning. I need some advice on how to deal with green and
semi-dry wood. Specifically:
- For bowl blanks that I purchase, I usually cut out a round piece and
seal the edges. About how would it take to dry like this? If I rough out
the bowl, would it dry faster? And should I still seal the roughed-out
bowl to prevent cracking?
- For green wood cut from downed trees, can I store it in the "half-log"
shape? How should it be sealed and stored?
- What's an acceptable moisture content for final turning?
Thanks for your help!

Although it is a more advanced technique (than drying), some turners
actually encourage interior mold by adding shavings, soil and other
debris in monitored conditions. Google around for this and dont forget
to wear a mask when messing with mold.
happy turning,
Max!

On Tue, 15 May 2007 14:03:15 -0400, James Edward
wrote:

Hi,
I am relatively new to turning and am trying to build up a stock of wood
for bowl turning. I need some advice on how to deal with green and
semi-dry wood. Specifically:
- For bowl blanks that I purchase, I usually cut out a round piece and
seal the edges. About how would it take to dry like this? If I rough out
the bowl, would it dry faster? And should I still seal the roughed-out
bowl to prevent cracking?
- For green wood cut from downed trees, can I store it in the "half-log"
shape? How should it be sealed and stored?
- What's an acceptable moisture content for final turning?
Thanks for your help!

You've already gotten some very good advice, but I do it differently-
mainly because I'm impatient, and don't take kindly to rules.

Whether I've purchased a blank or just got a log from somewhere, I
don't do much to it until I'm ready to go. Since 99.99999% of my
turning stock is free, and not all that hard to come by, I let it just
do what it is going to do, and if it cracks or does something else
that is particularly nasty, it makes a good campfire in the backyard.

I store my logs with the bark on, and standing on end. If they are in
the yard, they generally will spalt like this without too much
encouragement, and if they're in the garage, it just keeps the water
weight from settling to one side so that the blank is relatively
balanced when I turn it. I do not split them and store half logs, and
if you ask me, I think that's important. The bark will keep the log
from drying too quickly- though the ends will crack. How much the
ends crack depends on the wood, but it's generally not more than 2-3"
with the stuff I've done this to.

When it's time to turn something, I cut off just what I need with the
chainsaw. That being said, I did cut up a lot of square blanks about
a year ago in the interest of experimentation, and put half of them in
the shed out of the sun, and half of them out in the yard unprotected.
The ones outside cracked, the ones in the shed are fine- make what you
will of that. They were all stickered to allow air to move freely
around the entire blank.

Here's where my technique really differs- I don't rough turn, dry, and
then finish turn. I almost always turn the piece to finished
dimensions in one shot. For this to work, it helps to turn your
pieces thin- 1/16" - 5/16" thick walls.

When I start to get a piece near it's final shape, I start *sanding*
it. What I'm really doing is using worn sandpaper to friction-heat
the turning with the lathe at a high speed. You don't want to burn
the wood, but hot is good. It can burn your fingers, so be careful.
I alternate between this and truing up the blank with a chisel until
I'm ready for the final sanding. By the time I get there, the wood is
obviously dry everywhere but the bottom, where the tenon is still
attached (you can see the color change as the wood dries out).

I then lower the speed to 300-600 rpm, and sand through the grits
until I'm happy with it. Yes, this can take a long time- I usually
spend as much or more time sanding than I do cutting. When it's
ready, I part off the piece, and sand the bottom until *it* is dry.

Then I finish it off the lathe- I used to do the finishing on the
machine, but I personally found it to just be too messy.

For what it's worth, I lose very few pieces to cracking using this
method- perhaps one in twenty. Even better, it allows me to whip
things out in an evening even though I didn't plan six months to a
year in advance. About two of every five pieces does warp to a
slightly obround shape, but it is usually still pleasing- provided the
pith runs parallel to the base, the distortion comes out even.

If I need something to be dimensionally stable, I either make a
segemented turning from kiln-dried lumber or simply laminate matching
flat lumber to make a blank. The way I see it, dimensional stability
is for utilitarian items, and does not need to have wonderful grain or
be made from one piece of wood. Those items that are mainly for
aestetic enjoyment are perfectly fine with a little distortion, IMO.
(and of course, some segmented turnings are amazing.)

All that being said, you might follow what I do exactly, and
experience a lot of failures. I generally turn maple, willow, and
yellow birch, with a handful of fruit woods in the mix when I can find
them, and they all behave themselves. A different climate or species
of wood may make all the difference, though!

In article ,
James Edward wrote:

Hi,
I am relatively new to turning and am trying to build up a stock of wood
for bowl turning. I need some advice on how to deal with green and
semi-dry wood. Specifically:
- For bowl blanks that I purchase, I usually cut out a round piece and
seal the edges. About how would it take to dry like this? If I rough out
the bowl, would it dry faster? And should I still seal the roughed-out
bowl to prevent cracking?
- For green wood cut from downed trees, can I store it in the "half-log"
shape? How should it be sealed and stored?
- What's an acceptable moisture content for final turning?
Thanks for your help!

In addition to Fred's fine advise, a wood dryer built out of a old steel
REFER (using a light bulb for a heat source) or a box built out of
insulating foam (again using a light blub). Me, if I need to hurry the
work, I use a microwave.

Just had a thought... what are the light-blub dryings going to do when
they "ban" the old style light blub?

--
--------------------------------------------------------
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 James, Many straight grain timbers left alone will crack with one
large radial split from bark to pith along the length of a short log. If
such a local timber is plentiful enough to allow for some loss
(transition to firewood) the green timber bark and all, can be cut into
short logs and left to split naturally and dry or spalt.

When you are ready to turn something or you are told to get rid of that
ugly mess, you can often get two reasonably equal turning halves by
splitting along the big crack and cutting off a couple of inches at the
ends. Not a 100% save with every log, but no method in dealing with
green logs is. For that matter, most everything we do in woodturning
must deal with probability.


Turn to Safety, Arch
Fortiter


http://community.webtv.net/almcc/MacsMusings

In article ,
(Arch) wrote:

Hi James, Many straight grain timbers left alone will crack with one
large radial split from bark to pith along the length of a short log.

But often the splits start out in different places at each end - a
considerable yield improvement at fairly low workload can be had by
making a single cut from bark to pith along the green log, providing a
pre-made "split" for nearly all of the shrinkage to accumulate in.

--
Cats, coffee, chocolate...vices to live by