Tom Nie said:

I didn't make myself clear. The solid part I was referring to was the lower
portion of the bowl between the two segmented layers at the top and the
segmented bottom.

Tom,

Actually, you were quite clear, I simply exhibited the far too common
Usenet trait of not paying complete attention to what you said.
It's been a really bad week...

I have seen what you describe...
Similar to this fine bowl by Kevin Neeley, I assume:

http://www.turnedwood.com/images/Bowl0745b.jpg

I have never tried it, and don't have any big dried blanks to work
with. That is one advantage of turning kiln fried woods. They are
already at a consistent moisture content, ergo the parts that make up
the bowl segments are also consistent. This ensures that
expansion/contraction should relatively predictable, and that
(hopefully) nothing should crack after a few seasons.

Turning a block of green wood and then trying to glue up with kiln
fried segments would require a considerable amount of time for drying
and equalization, or as the green blank dried, the segments would pop
off like a '69 Ford LTD hubcap.

I've never seen a 10" x 10" x 4" kiln fried butternut blank for sale,
and at the price of wood these days, I'm not sure I want to. Same
with Cherry, Maple, etc. When I turn large monolithic blanks, I
generally use green wood collected myself. Being relatively poor,
it's generally a requirement. :-|

I think the segmented bottom adds to the attractiveness of the piece. Just a
plain center/bottom bowl part seemed like it would add drama. I'm not an
arteeest so maybe my thought is goofy.

As demonstrated by the above referenced bowl, not goofy at all.
Expensive and time consuming perhaps, but looks good to me.

Now your feelings of disparate movement may still be your answer. I guess
you'd have to assemble your segments, then add to a solid blank, then turn
and hollow about like normal. Then add to your segmented bottom.

With dried woods and MC equalization, it should be doable, albeit at a
price. I still worry about the differing expansion characteristics of
the various parts. The large monolithic blank would expand greatly
cross grain in one direction, but the segmented rings would expand to
a lesser extent in all directions. I assume you would have to pay
particular attention to the expansion percentages of the chosen woods,
turn somewhat thin, and it might possibly require the use of veneer
layers and a pliable glue to offset the tendency of the pieces to
crack apart at the glue lines.

I'm certainly no expert, but that's my take on it all...

FWIW,


Greg G.