Coloring Concrete,
Release Agents
Here’s some expert advice on how to choose between liquid and powdered release agents for your decorative concrete stamping applications. Also included are tips on applying the release agents, removing them after stamping, and storage.
by John Strieder
to keep it from sticking to a stamp, there are two ways to go: liquid or powder. Each has advantages, but each also causes problems.
Contractors who use powder release must wash it off afterward, while liquid evaporates on its own, an extremely handy feature to consider when stamping indoors or near a pool. But powder release agents are the only ones that come with color. Liquid release agents are colorless.
So, for a decorative concrete contractor, the choice can be a tough one.
Powder or 'cast-on" release agents have the consistency of baby powder, which allows them to resist both wet concrete and rubber stamp but gives them the tendency to get all over everything else.
They're typically made with paraffin, which resists adhesion to many surfaces. The fine grit of the powder repels water, as well as damp concrete. Powders are typically colored, but can also be white, which leaves no tint behind after the release is washed away.
When a stamp presses into a layer of powder release, the powder will be pressed most heavily into the edges of joints, cracks and pattern lines, thereby creating shading. The paraffin-based particles carry particles of dye, which are absorbed by the moisture in the concrete, explains George Lacker, owner of GLC3 Concrete, a contracting firm based in Plantation, Fla. After the paraffin material is hosed off, the dye remains. "It's pretty much like staining it," Lacker says.
Applying two or three levels of powder release on top of each other before stamping creates all sorts of possibilities for natural-looking effects, such as the multicolored look of natural stone. "It leaves a lot of colors and mottling that looks fairly natural," says Clark Branum, technical director at Brickform Products. "When washing off powder, contractors can control how much of each color to take and leave."
According to Steve Johnson, marketing and product development, ready-mix division, for Solomon Colors, powder has no equal in the multicolor effects department. "Powder release is the fastest method to get multiple colors," he says.
But powder releases are also messy. Hanging clouds of the fine dust will settle in nostrils and on clothes, walls and furniture.
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