DIYbanter - Turning Green Wood

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Turning Green Wood

I am new to turning and recently turned a bowl from green wood (fresh
cut, really fresh). Took it off the chuck and set it inside to dry out
a bit and it split badly. I have read that you can turn green wood,
but nothing about keeping it from splitting. Any suggestions for a
turning "greenie"?

Turning Green Wood

Get Michael O'Donnell's book "Turning Green Wood". It will give you all
the answers. It's a great book. To keep green wood from splitting you
can't let it dry out until you are done. You must keep it damp and you
must turn the walls thin and to a consistent thickness. Thin at top and
thick at bottom will guarantee splitting. Spray it with water if have
to to keep it moist while turning. Also, if you use fruit woods, they
are much more likely to split. This is not to say that the bowl won't
warp...it will but that is often the charm of turning green wood.

If you don't want splitting or warping, search out past threads about
alcohol, liquid detergent and microwaving rough turned bowls.

Turning Green Wood

Hi Morbius,

There are a couple things you can do to prevent splitting.
1. Turn the walls to a thin consistent thickness.
2. Do what is called twice turned bowls. First you shape the outside of the
bowl. Then start the hollowing process, until you have 3/4" - 1" wall
thickness.
Then remove the bowl from the lathe, and set it aside for a couple months
to dry. If you are in a dry climate you will want to place the blank in a
paper bag or wrap it in newspaper to slow the drying process. The blank will
be warped when dry. Don't worry that's natural.
3. When the black is dry, remount it on the lathe and reshape the outside.
Then finish the hollowing of the inside.
When done no more splitting or warping.

Good Luck.

Dan
"Moribus" wrote in message
oups.com...
I am new to turning and recently turned a bowl from green wood (fresh
cut, really fresh). Took it off the chuck and set it inside to dry out
a bit and it split badly. I have read that you can turn green wood,
but nothing about keeping it from splitting. Any suggestions for a
turning "greenie"?

Turning Green Wood

Moribus
on my web site I discuss turning from green wood to a finished bowl.

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

Turning Green Wood

"Moribus" wrote in message
oups.com...
I am new to turning and recently turned a bowl from green wood (fresh
cut, really fresh). Took it off the chuck and set it inside to dry out
a bit and it split badly. I have read that you can turn green wood,
but nothing about keeping it from splitting. Any suggestions for a
turning "greenie"?

Yep. http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm Read
chapter three with special attention.

1) Wood begins to warp once the moisture content is ~30 % by weight. Warp
causes checks which can lead to cracks.
2) It's radical difference in moisture content between interior and exterior
which we must avoid. Fully expanded fiber close to fully contracted equals
stress, which might exceed the strength of the material.
3) Wood eventually reaches equilibrium with the atmosphere, with relative
humidity directly correlating to moisture content. Tables in the text
should become a part of your wall in the shop.

Our task is to control the rate of surface loss to within the range of
interior replacement while the wood dries from 30% to around 10%. We do
this by controlling the relative humidity around the wood. Buy a
hygrometer, because, though there are many ways to control relative
humidity, they may be unnecessary. First know what your RH is, then decide
if you need to increase it by enclosing your piece.

I like paper tenting, because it's cheap, and paper is, after all, wood, and
becomes a new disposable outer layer.

You've also heard a couple of turner legends in the replies so far.

Magic potions, incantations and methods to prevent drying degrade exist only
in the minds of turners. Rest of the lumber industry controls the rate of
moisture loss and accepts that wood is anisotropic. Could be they're
wrong, but if you look at Fig 3-3 and then the construction lumber at Home
Depot, you'll see a remarkable coincidence. Your bowls will do the same, so
plan for it.

Turnings need to be uniformly thin. Not so. An eight-foot board dries at
the same rate as a 5 footer. Since the standard cross-grain bowl turning
normally has no point more than a couple of inches from open end grain, this
is the proper analogy.

Turning Green Wood

Moribus wrote:
I am new to turning and recently turned a bowl from green wood (fresh
cut, really fresh). Took it off the chuck and set it inside to dry out
a bit and it split badly. I have read that you can turn green wood,
but nothing about keeping it from splitting. Any suggestions for a
turning "greenie"?

What species of wood? Some behave better than others while drying.

A bowl that is being finished in one turning needs to be turned thin
enough that it can flex as it dries, rather than split. 6mm - 10mm
should be ok. OTOH, if you are doing a twice turned bowl to get a round
finish, the walls will have to be much thicker, in which case I seal the
endgrain areas with wax emulsion.

Taking the piece inside to dry was probably a mistake, depending on the
current climate where you live. It needs to dry slowly, starting in a
cool damp (high relative humidity) environment and later into warmer
drier environment. A hydrometer is a useful tool to have. I like to
start drying at over 70%RH and finish at less than 40%RH, or
thereabouts. It's not rocket science. If your climate is too dry for the
initial drying, you can increase it locally by wrapping in paper or
burying in wet shavings as someone else mentioned.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com - a blog for my customers
http://www.seafoamwoodturning.com/TheToolrest/ - a blog for woodturners

Turning Green Wood

Wow! All these big time, serious posts here full of real information.

All I was going to say was don't leave your piece in the chuck, as it
may easily rust it. Number the jaw positions on the piece, take it off
and put it in a plastic bag sealed tightly until you are ready to
return to it.

And read everything above.

Robert

Turning Green Wood

"Leif Thorvaldson" wrote in message
...

"Moribus" wrote in message
oups.com...
I am new to turning and recently turned a bowl from green wood (fresh
cut, really fresh). Took it off the chuck and set it inside to dry out
a bit and it split badly. I have read that you can turn green wood,
but nothing about keeping it from splitting. Any suggestions for a
turning "greenie"?

Think LDD!!*G*

Leif

Leif,does it matter what brand of LDD. I read you & Ron Kents articles on
this. TIA
Lyndell