FIMO is the oldest name in polymer clay. It goes back to 1939 in Germany — the name comes from Fifi Rehbinder, the dollmaker’s daughter who developed it — and Staedtler still makes it in Germany today.

FIMO Professional is the firm, densely pigmented member of the FIMO family, and it is what serious clayers reach for. It holds its shape and its detail through handling, and it cures exceptionally strong.

The True Colors mixing system. Professional is built around five pure mixing colors — yellow, red, magenta, green and blue — plus black and white. Staedtler publish the ratios, so a shade you mix today you can mix again next month and get the same result. That reproducibility is the whole reason the line exists, and it is what makes Professional the sensible choice if you sell your work.

Good for: caning and millefiori, mokume gane, Skinner blends, crisp cut shapes, and any piece that has to hold a fine edge.

Worth knowing: Professional is firmer than FIMO Soft and it wants proper conditioning before it behaves. That firmness is the point rather than a fault — it is what lets the clay keep an edge. If you would rather have clay that is ready to shape straight out of the pack, buy FIMO Soft instead.

Baking. FIMO cures at 230°F (110°C) for 30 minutes. That is considerably cooler than Sculpey, so if you have been baking Sculpey, do not carry the same oven setting over — too hot and FIMO scorches and darkens. Thicker pieces are happy with longer at the right temperature; there is no penalty for extra time. Most home ovens run well off their dial, so an oven thermometer is the single most useful thing you can add to your setup, and underbaking is the usual reason a finished piece turns out weak.

Specification. 2 oz (57 g) bar. Staedtler item 8040-23. Cures at 230°F (110°C) for 30 minutes.

Staedtler’s own page for FIMO Professional · Ginger Davis Allman’s polymer clay brand comparison at The Blue Bottle Tree