It is more difficult to get adhesives to bond to a polypropolene cone than to a standard paper cone. To deal with this, use a Very LIGHT grade sandpaper and scuff the edge of the cone that will attach to the foam to create a better bonding surface for the adhesives.
Cathy grew up in NY, moved to Florida in 1975 and graduated from the University of South Florida, with a degree in broadcasting. She and her husband Glenn started The Speaker Exchange in 1977. (Glenn later moved into Audio/Video sales and installations). In 1979, Cathy went to California for JBL speaker repair training and later received advanced training from Frank Spain, the then head of the Electro-Voice service department. She has continued to advance her audio education through many CES, NAMM, and CEDIA trade show classes.