Same clay as bowl, no flocs added, yogurt consistancy, slip put through a 60 mesh screen then thumped on the table to remove air bubbles. Sherril tiny red kidney shaped rib, but any really flexible rib works. Slip done right after bowl thrown. Fast wheel with a slow hand movement or slow wheel with a faster hand movement, whatever works to get the design you are looking for. I prefer a looser spiral so usually pull through the slip with slight in and out movement. It's lots of fun, if you mess it up just start over again. For about a 16" or so diameter bowl I'll spread about 1/3 cup of slip in it then start in the middle and work outwards, removing a lot of the slip. There isn't much slip left between the lines.