I used to use the conference room table at work -- taped the backing quite tautly and then made the sandwich and pinned. It was a GREAT table: solid oak and seated twenty-four, so it just went on forever. In addition, the east wall was all window 3 feet from the floor on up! Great natural light! But the executive assistant decided to have the table surface completely sanded and refinished and now it is a total No-No to touch the thing much less stick a pin in it!! LOL The last quilt I pinned up was at the fabric shop in the classroom, but the tables are plastic and they're not very big. Another place to try: the public library has meeting rooms with big tables.