Solid Colour Pastes

Solid colour paste is a concentrated pigment preparation used to give compatible epoxy resin strong, generally opaque colour. The pigment is dispersed throughout the resin rather than simply colouring its surface. This makes solid colour pastes useful for decorative castings, inlays, furniture and other resin projects where transparency is not required.

Solid colour paste is primarily used to create opaque or substantially opaque resin, while translucent dye adds colour while allowing more light to pass through the casting. A solid pigment is therefore suited to bold, defined colours and concealed backgrounds, whereas translucent dyes are better suited to glass-like effects where visual depth and transparency are important.

Measure the resin and hardener according to the epoxy manufacturer's specified ratio and mix them thoroughly. The pigment paste can then be incorporated according to the instructions for the particular resin and colourant, making sure it is evenly dispersed throughout the batch. Scrape the sides and bottom of the mixing container as required so that neither unmixed epoxy nor concentrated pigment remains.

The amount required varies with the concentration of the paste, resin system and desired opacity. Start with a small quantity, mix thoroughly and add more only if necessary. Always stay within the epoxy manufacturer's maximum recommended pigment or additive loading. If a particular colour needs to be reproduced later, measuring the pigment rather than estimating it by eye will give more consistent results.

Compatible pigment pastes can be combined to develop custom colours. For repeatable results, record the proportions used in successful test batches and scale them accurately for the final pour. Remember that the appearance of concentrated paste can differ from the colour produced when it is dispersed through epoxy, so assess a properly mixed sample rather than judging the pigment directly from its container.

Where all products are compatible with the epoxy system, mica powder can be combined with coloured resin to introduce metallic or pearlescent highlights. An opaque base colour can provide strong contrast behind reflective mica particles, although too much solid pigment may change the visibility of the mica effect. Small test batches are useful for finding a suitable balance between opacity, colour and shimmer.

Excessive quantities of additives can interfere with the intended properties of some epoxy systems, particularly where a pigment paste contains components other than dry pigment. Adding more colour is therefore not always better. Follow the resin and pigment manufacturers' recommended loading rates and use a sufficiently concentrated colourant when strong opacity is required rather than exceeding those limits.