Mold Sealer S-31 is a semi-permanent mold sealer in the field of thermoset processing. It can be used for all types of resin and all kinds of processing, but especially for molds with highly porous surfaces. The operating temperature range of Mold Sealer S-31 is between room-temperature and +475°C. Processed correctly, Mold Sealer S-31 will leave a high gloss surface.