What Are the Essentials of GRC Decorative Panel Sanding: A Complete Analysis from Tool Selection to Operating Techniques

Details determine quality, and craftsmanship creates classics—the grinding process of GRC decorative panels is a perfect fusion of material and art.

In the field of architectural decoration, GRC (Glass Fiber Reinforced Concrete), with its advantages of light weight, high strength, and rich shaping possibilities, has become the preferred material for high-end projects such as grand theaters, commercial complexes, and landmark buildings. As a critical step in the production of GRC decorative panels, the grinding process directly affects the product's surface texture, installation precision, and durability. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group will provide an in-depth analysis of the core points of the GRC decorative panel grinding process from three dimensions—tool selection, operating techniques, and quality control—offering professional solutions for designers and owners.

### I. Scientific Selection of Grinding Tools for GRC Decorative Panels: Balancing Efficiency and Precision

The selection of grinding tools is the foundation of process success and must be precisely matched to the material characteristics of GRC decorative panels (including the glass fiber reinforcement layer and cement-based matrix) and surface requirements (such as stone-like textures and smoothness). In production, Qinglong adopts a three-tier tool system: in the rough grinding stage, 80-120 grit diamond grinding wheel discs are used to quickly remove air bubbles, burrs, and mold marks from the component surface, while for special-shaped lines (such as Roman columns and cornice lines), handheld angle grinders are used to ensure uniform grinding of curved surfaces; in the medium grinding stage, 240-400 grit resin abrasive discs are used, focusing on treating scratches left after rough grinding and improving surface flatness—at this stage, orbital sanders can be used in combination to improve the grinding efficiency of large-area panels; in the fine grinding stage, 600-800 grit sponge sandpaper is used to achieve a mirror finish through manual or mechanical polishing, especially suitable for scenes with extremely high visual texture requirements, such as commercial building exteriors and museum walls. It is worth noting that the tool rotation speed must be controlled at 800-1500 rpm to avoid overheating and carbonization of the GRC surface caused by high-speed friction, which would compromise the material strength.

### II. Grinding Operation Techniques for GRC Decorative Panels: Standardized Processes and Craftsmanship Details

Standardized operating procedures are the core of ensuring grinding quality. Drawing on 28 years of construction experience, Qinglong has developed the “Three Fixeds and Three Checks” operation method: the “Three Fixeds” mean fixing the direction (grinding in a unified direction along the texture or as required by the design), fixing the force (applying uniform pressure of 1.5-2 kg to avoid excessive local grinding that causes thickness deviation), and fixing the area (dividing the surface into 30cm×30cm grinding units to prevent missed or repeated grinding); the “Three Checks” mean checking flatness (measured with a 2-meter straightedge, with error ≤2mm/m), checking glossiness (using a gloss meter, controlled at 30-70 GU according to design requirements), and checking edge and corner integrity (arc radius deviation ≤1mm). For complex-shaped GRC components such as double-curved surfaces and openwork reliefs, Qinglong uses 3D scanning technology to pre-generate grinding paths, combined with robot-assisted grinding, to ensure that every detail accurately reproduces the design drawings. In addition, the grinding environment must be kept dry and well-ventilated to prevent dust accumulation from affecting the surface finish, and operators must wear dust masks and gloves, practicing the “safety first” production philosophy.

### III. Grinding Quality Control for GRC Decorative Panels: Full-Chain Quality Control and Industry Standard Practices

As a participating drafting unit of the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), Qinglong has established a strict grinding quality traceability system. Each GRC decorative panel must undergo three inspections after grinding: the initial inspection involves surface defect self-checks by the production team; the re-inspection uses dedicated lighting (checking for scratches and color differences under 500 lux strong light); and the final inspection is conducted by the quality control department, which tests surface hardness (≥65 Shore D) in accordance with GB/T 2567-2008 Test Methods for Properties of Resin Castings. For GRC products exported to overseas projects in Malaysia, Australia, and other countries, the products must additionally meet the freeze-thaw resistance and abrasion resistance requirements of ASTM C1185 Standard Specification for Glass Fiber Reinforced Concrete Products. Through the closed-loop management of “production-grinding-inspection,” Qinglong keeps the defect rate of the grinding process below 0.5%, ensuring that its products satisfy both designers' aesthetic pursuits and the safety standards of building structures.

The grinding process is the key to the transformation of GRC decorative panels from “industrial products” to “architectural artworks.” Supported by 28 years of technical accumulation, Qinglong Group seamlessly integrates deepened design, manufacturing, and construction installation. Through scientific tool selection, standardized operating procedures, and rigorous quality control, it provides customers with GRC solutions that combine aesthetics and durability. Going forward, Qinglong will continue to uphold the principle of “meticulous work and the pursuit of excellence,” deepen innovation in the UHPC/GRC/GRG/GRP niche segments, and continuously empower its mission of “creating beautiful architecture.”