How do yall flatten the bottom of bowls that are turned to finish green and let warp and dry?Remount and turn the bottom flat, or sand flat so it sits flat on table?
How do yall flatten the bottom of bowls that are turned to finish green and let warp and dry?Remount and turn the bottom flat, or sand flat so it sits flat on table?
Remount and turn flat. I use a jamb chuck and a live center to hold it. This leaves a 1/4" nub that I finally clip off with pliers. I then sand it off the lathe.
Also, I usually finish the bottom slightly concave.
I think Prashun's method is widely used and accepted. I typically use a wide sweep carving gouge to remove most of the nub to reduce sanding.
I've used John and Prshun's method, too. I've also sanded the flat by holding the bottom against a lathe-mounted sanding disk. The decision as to which to use is based mainly on how far out of flat the bottom is.
Grant
Ottawa ON
I leave a ring for the foot (bottom is hollow) when I turn the bowl. This makes it easy to level after drying because only a little bit of wood has to be removed.
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Sonny - I'm a newer turner too. This is what I have learned. Since you will probably need to turn inside and out use your chuck with standard (or larger) jaws for the jam chuck and center the bottom to your live-center at the tail. Clean up the tenon so it's round again with flat bottom (light cuts) and mount in the chuck. Now you can clean up inside then outside. After this use a vacuum chuck or cole jaws to hold the bowl and finish the bottom. May want to use the tail stock to hold till you get to the final nub.
(this is somewhat similar to discussed above)
Mike
I like the fairly narrow ring around the outside of the foot. When dry any uneveness can be easily removed without turning by flattening on a piece of sandpaper on a flat surface. (I have some 24" wide 220 grit for the occasional large sanding task.) The table saw top makes a good flat surface. If the sides of the ring are fairly steep for at least a little bit, removing a little wood this way does not make part of the foot visibly wider in places as it might if the sides had a shallow angle.
JKJ
I never bother with that. I use a recess, and don't turn that off either. Only person who commented on my bowls rocking was a ceramic artist. When you explain the warping part of the drying, and that is why it rocks, it still gets the 'oh, that's so organic!' comment...
robo hippy