The story with poly over Shellac is that water-based poly will not adhere well to most commercially prepared Shellac coatings due to the wax they contain. Poly that has a mineral spirit solvent base will, so whether or not you do is simply a matter of personal taste.
Hank Metz, "A Woodworker's Notebook" http://www.ameritech.net/users/hankm/index.htm Get it now with the "Open Ship" program: http://www.ameritech.net/users/hankm/vidorder.htm
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