Hi Bruce
Boy, are you opening up a can of worms or at least a hollow form of bugs. I
have turned a lot of hollow forms and vases and rarely finish the inside,
especially of art pieces. In this I have followed the pattern of David
Ellsworth and John Jordan, as well as a host of others, so as to put myself
in good company. My understandng is wood moves with the addition and loss of
water, generally as a result of relative humidity in the air. The movement
of relatively dry wood in relatively even humidity fluctuations is small and
gradual while the circular form is inherently strong (witness the egg). In
addition the loss and gain is greater on the outside than the inside of the
form both because of smaller surface area and because of the enclosed air
mass. This allows us to get away with a finish on the outside and not the
inside without serious problems due to unequal movement and stresses.
I think.
Experience says it works :-)

--
God bless and safe turning
Darrell Feltmate
Truro, NS Canada
http://aroundthewoods.com
http://roundopinions.blogspot.com
"Bruce Ferguson" wrote in message
...
Darrell, a question. I see you don't finish the insides and I keep
reading about putting finish on both sides of a board so the wood will not
take up moisture on one side to cause warping or wood movement. This is
not true of hollow forms?

Bruce


Darrell Feltmate wrote:
I have the hollow form almost completed. The turning is done and the
bottom is sanded and signed, but I have to get a few coats of finish on
it for final pictures. Meantime I have some photos of the start of the
next burl vase. I should have them up sometime soon. Anyway the bottom is
at http://aroundthewoods.com/workinprog...uceburl10.html