BEECK Etching Fluid reliably removes sinter skin, a vitreous glossy high-tension and impermeable accumulation of binder on the surface of felted and floated lime and lime-cement renders. An unremoved sinter skin is a substrate defect according to VOB/C and poses the risk of stress-induced spalling, for example during driving rain. The gas-tight sinter layer also disrupts the carbonation and recrystallisation of "healthy" lime renders and plasters. They become worn and crumbly underneath the glass-hard layer. Creating a stress-free, porous and firm, surface zone is particularly important for pore deep, permanent silicification of active silicate paints such as BEECK Pure Crystalline and Beeckosil. At the same time, a uniformly absorbent homogeneous surface is created by the etching, which makes it possible to apply smooth, seamless and stain-free mineral coatings.
The acid neutralises within a few minutes on the highly alkaline substrate. Rinsing with water is therefore not for neutralisation purposes, but instead to remove exposed textural and aggregate particles on the surface of the render. Especially in interior areas, these can also be removed from the plaster with a stiff broom before coating.