This is the basic inlay slip recipe suggested by Steven Young Lee in his March 2010 article for Ceramic Arts Daily. The only difference is the 1:1 substitution of Glomax (a commercial calcinated kaolin) for the XX Sagger Clay originally in the article.
30 Grolleg 15 EPK 25 XX Sagger Clay or calcinated kaolin 15 Nepheline syenite 15 325 Flint
add: 4 Cobalt oxide 4 Manganese dioxide 6 Red iron oxide 2 Chrome oxide
I'm using this recipe as my base slip for exploring bisque fired line inlay this fall.