What Matters in the Sanding Process for GRC Decorative Panels? Key Steps and Quality Control Points Explained

In the field of architectural decoration, details determine quality, and the grinding process of GRC decorative panels is a core step that determines the final presentation. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group deeply understands the importance of the grinding process to project quality. This article provides an in-depth analysis of the key steps and quality control points of the GRC decorative panel grinding process, offering a professional process reference for designers and owners.

### Core Value of the GRC Decorative Panel Grinding Process and Industry Standards GRC (Glass Fiber Reinforced Concrete), with its advantages of light weight, high strength and flexible shaping, is widely used in high-end projects such as grand theaters, commercial complexes and landmark buildings. The grinding process not only affects the surface flatness and aesthetics of decorative panels, but also directly relates to the adhesion and durability of subsequent coatings. The Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), which Qinglong Group participated in formulating, clearly stipulates that the surface roughness of GRC decorative panels must be controlled within Ra2.5-Ra6.3μm, with no obvious sand holes, air bubbles or exposed fibers. This standard has become an important basis for industry quality control.

### Key Steps: Full-Process Control from Rough Grinding to Fine Finishing **1. Initial Grinding: Basic Contour Shaping** After demolding, GRC components must first undergo initial grinding with 80-120 grit sandpaper or grinding wheels, focusing on mold joint marks, flash and surface protrusions. At this stage, attention must be paid to applying uniform force to avoid thickness deviation caused by excessive local grinding. Qinglong's production base uses automated grinding equipment combined with manual calibration, ensuring that initial grinding efficiency is increased by 30% while errors are controlled within ±0.5mm. **2. Intermediate Grinding: Fine Leveling and Defect Repair** Use 180-240 grit sandpaper for a second surface grinding, focusing on eliminating initial grinding marks and repairing defects such as air holes and cracks. Qinglong's original 'layered filling method'—repairing layer by layer with GRC repair mortar of the same mix ratio—ensures that repaired areas bond tightly with the base material, preventing later cracking. This step requires real-time monitoring of surface flatness through 3D scanning technology to ensure errors do not exceed 1mm/m. **3. Fine Grinding: Texture and Gloss Shaping** Select 320-600 grit sandpaper for fine grinding according to design requirements. Stone-imitation components must retain their natural texture, while mirror-finish components must achieve a mirror-like fineness. Qinglong has developed specialized grinding tools for different finish effects: flexible grinding heads for special-shaped components and mechanical track grinding for straight lines, ensuring grinding uniformity per square meter is raised to over 98%. **4. Dust Removal and Quality Inspection: Details Determine Success or Failure** After grinding, high-pressure dust removal must be performed to clear surface dust and avoid affecting coating adhesion. Quality inspection adopts a 'double inspection system': first checking for surface defects under strong light, then conducting quantitative testing with a roughness meter to ensure compliance with Qinglong's internal control standards (10% higher than industry standards).

### Quality Control Points: Comprehensive Assurance from Raw Materials to Process **1. Material Compatibility Control** The fiber content and cement grade of the GRC base material directly affect the grinding result. Qinglong uses high-purity alkali-resistant glass fiber (content ≥5%) and rapid-hardening sulphoaluminate cement to ensure component strength reaches over 20MPa, avoiding 'chipping' and 'sand rising' during grinding. **2. Environmental Temperature and Humidity Management** The grinding environment must maintain a temperature of 15-25°C and humidity of 50%-70%. Excessively high humidity easily clogs sandpaper, while too low a temperature affects the curing of repair materials. Qinglong's production workshop is equipped with an intelligent environmental control system, maintaining constant temperature and humidity year-round to guarantee process stability. **3. Personnel Skill Standardization** All grinding workers must pass Qinglong's 'three-tier training system' (theoretical assessment + hands-on practice + project mentoring) and proficiently master the grinding parameters for different components. For example, hyperbolic GRC components require a grinding technique of 'from inside outward with spiral progression' to avoid surface cracking caused by stress concentration.

### Qinglong's Process Advantages: Technical Empowerment Built on 28 Years of Experience As a national high-tech enterprise and a drafting unit of GRC standards, Qinglong integrates its full-chain advantages into the grinding process: optimizing component shapes through BIM technology at the detailed design stage to reduce grinding difficulty; using automated production lines in production to ensure grinding precision; and providing integrated 'grinding-coating' services during construction and installation to avoid cross-operation contamination. From the GRC curtain wall of the Dongguan Women and Children's Activity Center to the translucent concrete project at Century Plaza on Nanjing East Road, Qinglong's grinding process has always followed the attitude of 'meticulousness and constant improvement', endowing buildings with delicate texture and lasting vitality.

The grinding process is the key transformation of GRC decorative panels from 'industrial products' to 'works of art'. Choosing a manufacturer with full-chain strength not only provides technical assurance but also achieves a perfect unity of design creativity and engineering implementation. With 28 years of professional experience, Qinglong Group is willing to provide a one-stop solution for every project, from detailed design to after-sales maintenance, to jointly create beautiful architecture.