One of our architectural precast customers wants to remove a thin skin from the surface of narrow bands on cladding panels. He wants a surface effect that's similar to that achieved by light abrasive blasting, but masking off the larger areas that won't lose the skin will be time-consuming. Is there an alternative to abrasive blasting?
Try light scaling to remove the surface skin. A new publication by the Precast/Prestressed Concrete Institute, Collection of Ideas on the Production of Architectural Precast Concrete (APC 1-98), gives the following description of this process. "Scaling is the lightest texture in bushhammered finishes. It is achieved by passing a triple-pronged scaler (originally developed to remove scale from steel prior to painting) singly or in gangs over the surface to remove only a thin skin. A single-head scaler is lightweight and can be readily manipulated by one person. No texture as such is brought out by this technique, although some aggregate is exposed and fractured in the process." You can purchase APC 1-98, which is an excellent source of useful production information, for a $15 member price or a $30 nonmember price, by calling PCI at 312-786-0300.