Yes you can add small amounts of materials like sand to achieve a specific finished result, but we recommend you use our powder additives instead. Some materials will damage your gun, and often settle to the bottom of the sprayed material resulting in no benefit. If an extremely coarse product is desired, we recommend you broadcast a fine layer after the base coat has partially cured. The resulting product could also be top coated after to encapsulate the sand or other material.
You can control flexibility as standard, soft, or hard and employ simple spray techniques obtain a rough to smoother surface using our powdered products without the need to add sand or other general materials. SL&C tech support is available 24 x 7 to help.