RustSeal Satin Black (and all matte sheens of RustSeal) are heavily pigmented. It is critically important to get all of the matting agents mixed back into suspension using a mechanical mixer attached to a drill (like the KBS Hurricane Paint Mixer) or at least a paint stir stick. Effective stirring/mixing includes repeatedly touching bottom of can and lifting to disperse any settled pigments and/or matting agents.
If RustSeal is not mixed well before each application and occasionally during application, the finish can turn out glossier than desired.
Be sure to also apply RustSeal in THIN COATS ONLY to allow for a nice matte finish.
If RustSeal is applied in medium or heavy coats, the finish can turn out glossier than desired.
If a more matte finish is desired, you can reduce RustSeal 20% with KBS #1 Thinner or Xylene to produce a more matte finish.
When RustSeal Satin Black is first applied, it can appear glossier than expected, but RustSeal Satin Black will matte down as it cures. Always wait for the full cure (24 hours) to evaluate the matte finish of RustSeal.
RustSeal Link -> https://www.kbs-coatings.com/rustseal
RustSeal Application Directions Link -> https://www.kbs-coatings.com/rustseal-directions