The most recent issue of Woodturning Design has an article on getting a
perfectly flat surface on a platter. After using a straight edge to get it
as flat as possible, the author power sands. Before he sands though, he
makes some radial pencil lines and gives a quick sanding, this will show the
slight ripple remaining. I don't have the article with me, so I might not
have it 100% right.
Martin

"billh" wrote in message
...
Large flat surfaces such as on flat platters or plates are a challenge
without a doubt. I use a straightedge but that won't necessarily catch the
very small waviness that shows up when finished. You can try shining a
light
on the surface at a shallow angle and your sense of touch can be a help.
If
you can feel it you can see it - note these are also drywall sanding
techniques as well.

I find that power sanding is better than hand sanding. If you are also
referring to the bump that appears in the center of bowl bottoms, I find
power sanding to be a great help since there is sandpaper "movement"
produced by the turning disk. When you hand sand in the center there is
very
little movement since the workpiece radius is very small which means you
remove less material at the absolute center and increasingly more as the
radius increases for a given application of the paper.
Billh

"Keith Young" wrote in message
...
Hi

I,ve been turning bowls now for a few years off and on. One thing that
bothers me is that every now and then after i finish one i notice that i
didn,t turn the bottom flat ( if that was my purpose.) Its only after
the
finish is applied that this becomes obvious.Any suggestions.

Keith