Best Floats for Applying Color Hardener

A resin hand float (top left) is often the tool of choice for working in color
hardener, vs. a magnesium float (bottom right).

Question:
Why is it recommended to use wood or resin floats when applying dry-shake color hardener?

Answer:
Wood and resin floats leave a rougher surface than magnesium or aluminum floats. The rougher concrete surface allows for more uniform moisture migration. Color hardener needs this surface moisture to react, or “wet out.” The hardener also needs to be worked into the concrete. The rougher surface of a wood or resin float provides better dispersion of the hardener and works it into the surface more evenly and consistently than a metal float. That said, using wood or resin floats to apply color hardener is considered best practice, not a hard-and-fast rule. There are many applicators who use metal floats successfully.