FIMO PROFESSIONAL POLYMER MODELLING OVEN BAKE CLAY. 85g Fimo Professional Blocks. Mix and match to create almost any colour - works with full Fimo Range. To set, place in preheated over at 110°C for 30 minutes. Huge colour range to choose from. Fimo Professional is harder and more pliable than standard Fimo Soft. FIMO Professional Polymer Clay is a premium formula of polymer clay designed for use by professional artists, designers and jewellers.