wrote in message
oups.com...
I am presently rough turning some green bowls and I need to dry them
without checking. I understand the wall thickness should be about 10%
of the diameter of the bowl and that I have to control the drying rate.
I believe this can be done by placing the bowls in a cardboard box and
setting it aside for a few months. What I am not sure of is how the
bowls have to be packed in the box, how much airspace they need or if
small pieces like under five inch diameter need to be packed at all.
Any information and hints on curing this green wood before finish
turning would be helpfull. Thanks Rod


Perpetual question. My recommendation is to take a look at
http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm especially
chapters two and three. That'll give you a good handle on how wood dries.

A reply to someone growing hairy mildew on one turning , posted by me,
recalls the two important moisture content levels. Until the unbound water
(the stuff that hits the wall when you turn) is gone, leaving the wood at
~30% moisture, no fiber collapse due to dehydration takes place. This is
not to say that there isn't a difference between inner and out. Indeed,
control of this gradient is what drying is about. But feel free to fling
all the water you can, and wait for the surface to look dry before putting
the piece into a controlled environment.

The second figure is ~20% moisture content, where nasty black mildew, which
leaves lasting stains, doesn't grow. So bag, coat, or wrap as desired once
the surface seems dry, though you might want to just leave it alone if
you've a fairly high RH. Stay ahead of mildew with ventilation and
rewrapping as required.

Oh yes, when you look at the information suggested, take a look at the
volumetric shrinkage rates, then use them and your desired wall thickness to
determine how thick to leave a blank. Thicker it is, longer it takes, and
it doesn't seem linear.