What Is Dry Tamped Cast Stone

Cast Stone is a form of precast concrete that is intended to simulate the look, texture and colors of natural stone. It is made from a refined mixture of natural and manufactured sands, white Portland cement and iron oxide colors. Whereas typical precast concrete (wet cast) is cast into forms in a semi-liquid state and left overnight to set, Dry Tamped Cast Stone is made from a "dry' zero slump mix, tamped into molds and immediately removed from the mold. Instead of one piece per day per mold  with wet cast, dry tamping allows multiple pieces per day from the same mold. The production per day is determined by the piece size and complexity. Up to 80 simple 16" x 16" medallions or 30 balusters per day is typical from an efficient motivated tamping station of 2 people.

This is a typical  24" x 24"pier cap wrapping around a steel post. The cap is made in 2 identical pieces. One tamping station could produce 50 halves per day.

This 24" Tall (600MM) baluster with
a rebar thru the center can be tamped
by one man. Using one mold he can make
at least 30 per day.

Wet Cast Cast Stone?
The definition of Cast Stone does not imply that to be "Cast Stone" the product must be dry tamped. The definition is that cast stone must resemble natural stone. Many producers make both wet cast and dry tamped and mix them on the same project.  Most architects picture precast as a gray concrete product with a smooth surface, an "as cast" finish with "bug holes" much like car wheel stops. To produce wet cast Cast Stone the mix design, sand/aggregate color, cement type and vibration process all contribute to a surface  that has few if any "bug holes". In most cases the surface film of cement is removed by light sandblasting or acid etching to allow the sand/aggregate color and texture to show. This is what gives the stone look. (See Sprint)

Producer Credits:  Pier Cap-Architectural Art Stone    Balusters: Continental Cast Stone

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