First, know that nothing is UV stable. Nothing will stop the effects of UV on these materials; the best you can do is delay it.
- Adding a UV Inhibitor: Smooth-On makes a product called Sun Devil that will be effective in delaying the effects of UV light on cured urethane rubber or plastic.
- Coloring Option: A way to achieve a uniform color and/or minimize the effects of UV would be to add UVO color pigment to the liquid urethane rubber or plastic product (A+B) and mix thoroughly. UVO pigment contains UV inhibitors that will aid in delaying the effects of UV light.
- Painting Option: Painting a cured urethane plastic casting with an acrylic or enamel paint will delay the effects of UV light on the casting. (Note; you cannot use acrylic or enamel paints to paint a cured flexible rubber casting).
- Use a urethane rubber or plastic product that already has a UV inhibitor in it. Smooth-On offers materials (such as Clear Flex Urethane Rubbers and Crystal Clear Urethane Plastics) that have UV inhibitors added as part of the formulation.
Related FAQ: The color of my urethane rubber is different compared to the last batch. Is there something wrong with the material? Will it perform the same as the last batch I received?