How Do I Colour Polyurethane Casting Resin Effectively?

Choosing Your Colouring Method

There are two main ways to add colour to polyurethane resin: tinting the liquid resin before pouring, or painting the cured surface. Directly mixing compatible dye concentrates into the liquid resin produces even, translucent or opaque colour throughout. Alcohol-based inks, such as Jacquard Pinata, can add vibrant effects, but it’s important to use them sparingly to preserve the resin’s properties.

If you prefer to add details or effects after your casting has cured, acrylic paints and alcohol inks work well on sanded, fully hardened resin. Always make sure the surface is clean and dry to ensure good adhesion.

Step-by-Step: Mixing Colour Into Polyurethane Resin

• First, measure your A and B resin components accurately and mix thoroughly according to your chosen resin’s instructions.
• Before pouring, add a few drops of resin-compatible dye or ink, mixing slowly to prevent bubbles. Avoid over-colouring, as excess pigment can affect curing or reduce strength.
• Test your colour on a small batch or sample piece so you can adjust before committing to a full pour.

For high-detail projects, like using IWhite Polyurethane Casting Resin, careful mixing ensures smooth, bubble-free results.

When Consistent Colour Matters

Colouring polyurethane resin is especially important when making jewellery, prototypes, miniatures, or replacement parts that require a precise or uniform finish. Mixing the colour into the resin is best for pieces that need to look polished and professional right out of the mould, while painting is ideal for artistic finishes, gradients, or post-cure corrections.