Refinish Table Stain/Glue Advice Pls?

You cannot glue the crack together cause the wood is so old and has dried and shrunk. Apply some glue to the bottom to seal the crack and prevent further separation. Now stain your top. To get a good finish on the top, use Marine Spar Varnish cut 3 parts varnish to 2 parts mineral spirits. This makes a thinner, easier to spread finish without leaving brush marks. Lightly sand and apply three coats. You will end up with a glass smooth finish on the top.