Shelf Life Shelf Life All GMS Composites prepreg systems are made to order. This ensures that customers receive fresh product with the maximum shelf life. Details on shelf life are available in individual GMS EP prepreg grade technical data sheets. Epoxy prepreg grades: To maintain the longest shelf life and tack life possible from date of manufacture, all epoxy prepregs should be kept by a fabricator as received in its sealed moisture proof bag and cold stored in a suitable freezer at a continuous temperature of ideally -18°C until needed. Storage in cold rooms at 0°C – 5°C is recommended where freezers are not available. Under ambient temperature conditions of 23°C, epoxy prepreg resins typically have a shelf life of around 3 – 8 weeks; this will vary depending on the specific prepreg grade and the amount of ambient temperature variation. BMI prepregs grades: GMS BP-190 high performance tooling prepreg, being BMI resin based, must be stored separately in a suitable cool room and kept at a constant temperature of between min. +1°C up to max. +5°C. Under these cool room storage conditions, GMS EP-190 tooling prepreg can be stored for over 6 months. To accuratelty monitor the ‘out life’ of a prepreg ( i.e. the maximum accumulated time allowed at room temperature between removal from the freezer and cure), it is recommended that a time sheet is kept to log the length of time a prepreg roll spends out of freezer storage and the ambient temperature at the time.