“IWHITE” WHITE POLYURETHANE CASTING RESIN – Two-Component A + B. Description. Highly fluid WHITE polyurethane casting resin with high hardening properties, for all kinds of handcrafted creations and fast prototyping in the modelling branch. Thanks to its high-speed catalysis (30 minutes), you can quickly reproduce objects of all sizes in a perfect way. In the liquid state, the resin can be easily coloured with any compatible colouring paste. Furthermore, once hardened it can be coloured with acrylic colours.