Various means of modifying liquid epoxide-resin systems to adapt them for specific uses are illustrated. The use of coal tar as a cheap diluent is described and its effects on some electrical properties of two typical epoxide-resin compositions are shown.Some mechanical and electrical properties of systems containing a new flexible diepoxide resin are indicated. Such systems are of potential interest for the encapsulation of components where good resistance to moderate temperatures and thermal shock is required.The results of the formulation of doughs and powders from liquid epoxide-resin systems are shown by reference to dough moulding compositions, moulding powders and powders for application by the fluidized-bed technique.