Post curing is a confusing subject for many people.  The majority of BJB materials are designed to cure at room temperature and will continue to improve physical properties over several days.  For some applications this may be sufficient but there are some instances where we need additional performance out of the same material. 

A post cure at elevated temperatures increases the level of cross-linking in two-component thermosetting systems.  In flexible materials this typically increases tear strength and tensile strength.  For rigid polyurethanes and epoxies the main improvement is an increase in the Heat Distortion Temperature (HDT) but you will also see a reduction in Cold Flow/Creep over time. 

Don't be fooled by claims that a thermosetting material does not have to be post cured; it's a half truth to say that.  The truth is you don't have to post cure, but don't expect the optimum performance properties stated on the Technical Data Sheet.  Even running a "mild" elevated temperature post cure can have benefits on the material.  We have many customers who do not want to subject their tools to extreme temperatures (above 150°F/65°C) so they run a mild post cure at 120°F/49°C to achieve a certain degree of improvement over a room temperature cure. 

Note that even silicone tools will improve physical properties and mold life if you run a post cure prior to putting the tool into service.  But be aware that high heat can swell silicones and may not be a suitable procedure for high tolerance tools.  Post curing is best done in a properly controlled parts oven (never a household oven).  Some materials can have undesirable results if subjected to extreme elevated temperatures (swelling, bubbles, deformation) so always check the recommended procedure on the Data Sheets or consult BJB's Technical Department.