This was a tough decision we had to make. We chose black because of its superior properties over brown or green material. The tests showed that Black Viton compared to Green or Brown Viton, with all parameters constant except for the color, is favorable. It has higher strength, better stability and better elastic properties originally (brand new), and also after exposure to extreme situations that cause material fatigue. It also possesses higher resistance to surface damage.
The production of any color material is feasible but requires the addition of pigments and other chemicals which by definition change the elastomer’s physical characteristics. As divers we are all highly sensitive to quality issues. We would be very reluctant to compromise any amount of quality for the sake of being able to identify Viton by color.
Furthermore we should be aware that nitrile-type and other materials may indeed be produced in green or brown or any other color we can imagine. If we judge only by color then there is a great risk of falling into errors. We have chosen to sacrifice the easy identification by color for getting the benefit of the best possible quality. The graphs below compare the characteristics within a range of DuPont’s Viton Elastomers (reference below). You will identify the superiority of black elastomer with regards to Tensile strength, elongation characteristics and stability overheat exposure:
