It depends on the finish. If it needs a lot of leveling and smoothing like a CA finish it will be done completely on the lathe. Most of my bowl finishes are either oil/varnish blends, shellac or lacquer. They are applied off the lathe and hand buffed/rubbed. I do like to apply a BLO/wax finish on the lathe. Apply the BLO while slowly spinning the piece. let it soak in a little while. Then crank the lathe up as fast as the piece will allow and burnish the BLO into the wood with a soft cloth. The high heat helps it to oxidize faster. Then wait as long as a smoke/beer/potty break and apply the paste wax the same way. That will give you a nice satin gloss and a very smooth feel to the touch.
Dave
