A medieval glass (dated from the beginning of the 16th century) decorated with prunts-a so-called Krautstrunk -- was restored. The glass came from the stores of the Museum of Arts in Duesseldorf. To complete the two missing parts of the side of the glass, colored polyester resin was poured between two wax plates which had been adhered to the glass by casting (3% methylethyl-ketone peroxide hardener). Since approximately half of the Krautstrunk had to be reconstructed, a wax pattern was made of the glass, from which a silicone rubber impression was made. After the wax pattern had been removed and a wax side had been prepared in the inside of the glass, polyester resin was filled into the gap between the adhered silicone rubber model and the wax side. The rim of the glass and the decorative glass filament of the Krautstrunk were reconstructed in the same way. Dental drills, abrasive paper and polish paste were used to remove all irregularities of the cast and helped to give the restored parts a glass-like look.