Immediately plunge it into LDD and let it soak for a half a day. Remove,
drip dry, wipe with shop towel, remount and start turning. That ought to
take care of any potential cracking or warping. I am just wondering if you
might not be having problems between softer grain wood and harder grain.
The softer comes out easier and can leave a ripple effect. This was
discussed quite a few posts ago. The considered opinion was that it wasn't
from harmonic vibrations, but from the variation in softness between the
grains.

Leif
"Barry N. Turner" wrote in message
...
I am turning a bowl (about 6" in diameter by about 6" deep, side grain)
from
green Black Walnut. I have shaped the exterior of the bowl. When I
started
to power sand, I noticed that the outside of the bowl had several
concentric
ripples. These ripples are a bit too deep to remove by power sanding, but
have eluded removal with a bowl gouge or scraper. I have not hollowed the
bowl yet, so it shouldn't be moving too much.

I have tried taking a very fine cut with a sharp bowl gouge, but the new
surface had just as many ripples. What is going on here? I'm pretty new
to
green wood turning. Do I just need to rough the bowl and let it dry for a
couple of weeks before I proceed? Any suggestions will be much
appreciated.
Thanks.

Barry