What Are the Surface Grinding and Putty Finishing Processes for GRG Components?

What are the surface grinding and putty application processes for GRG components? As the core finishing step in bringing special-shaped decoration projects to completion, the maturity of these processes directly determines the final appearance and installation compatibility of GRG finished products, and is also a key procedure that most engineering parties in the industry tend to overlook yet which directly affects project acceptance. Guangdong Qinglong Construction Engineering Co., Ltd., which has been deeply engaged in the GRG field for nearly 30 years, has drawn on implementation experience from over a thousand theaters, exhibition centers, and commercial complexes to develop a standardized grinding and putty treatment system adapted to different scenarios, providing the industry with a referable execution path.

1. Prerequisite Basic Requirements for GRG Component Grinding and Putty Application

Before officially starting the grinding and putty application procedures, the initial inspection and calibration of GRG components must first be completed—this is a preliminary step that most engineering teams tend to skip. First check whether the curvature of the component surfaces and the butt joint gaps meet the detailed design requirements. For components with deviations within 2mm, corrections can be made directly through subsequent procedures; for those with deviations exceeding 5mm, advance pre-adjustment is required to avoid the risk of the putty layer peeling off or cracking due to excessive thickness later. At the same time, residual release agent and loose sand on component surfaces should be cleaned in advance, keeping the substrate dry and free of oil stains—this is the core prerequisite for ensuring putty layer adhesion.

2. Phased Standardized Grinding Process

Grinding of GRG components is not completed in one pass, but follows the industry-standard “three-stage progressive grinding” approach, corresponding to different process nodes: The first stage is rough grinding after demolding, using 80-120 grit sandpaper to initially level the mold seams, flash, and protrusions on the component surface, focusing on addressing misalignment at splice points—the core of this step is to quickly correct visible defects from the forming stage without pursuing extreme smoothness; The second stage is fine grinding after putty application—after the first putty coat has completely dried, use 240-320 grit sandpaper to grind the entire putty layer, focusing on eliminating putty marks and pinholes, while grinding along the curvature of the component surface to avoid localized depressions that damage the original shape; The third stage is precision grinding before topcoating—use 600-800 grit sandpaper to lightly grind the entire surface, removing sandpaper marks left from the fine grinding stage, so the component surface feels uniformly smooth, providing a level substrate for subsequent topcoat spraying. For high-standard projects with seamless requirements, an additional polishing step with 1000 grit sandpaper is added to ensure completely smooth curved surface transitions with no breakpoints.

3. Core Putty Application Processes Adapted to Different Scenarios

The core function of putty application is to fill micropores and splice joints on the component surface while further calibrating overall flatness. The industry-standard putty application processes are mainly divided into three types: The first is general-purpose standard putty application, using GRG-specific gypsum-based putty material, applied in 2-3 thin coats with each coat no thicker than 0.5mm to avoid drying shrinkage cracking caused by thick application, with the next procedure carried out only after each coat has completely dried—suitable for GRG decorative components in most ordinary commercial spaces; The second is high-standard seamless putty application—for large-area curved ceiling projects in theaters and exhibition centers, dedicated fiberglass mesh is embedded at splice joints within the putty material, followed by overall putty leveling and grinding after complete drying, structurally preventing cracking at splice points caused by thermal expansion and contraction; this process is also one of the core procedures verified and matured by Qinglong in multiple landmark projects; The third is weather-resistant putty application for special scenarios—for GRG components in some semi-open spaces, modified putty material with waterproof additives is used to enhance the moisture resistance of the putty layer, avoiding efflorescence and peeling problems in humid environments.

4. Common Pitfall-Avoidance Points for Process Implementation

Common problems in the industry's GRG grinding and putty application stage are mainly concentrated in three aspects: First, mixing putty materials—some engineering parties use ordinary putty in place of GRG-specific putty to reduce costs, which easily leads to peeling and discoloration later; Second, skipping grinding stages—skipping rough grinding and going straight to fine grinding, leaving protruding defects on the component surface unable to be fully eliminated, resulting in a rough final appearance; Third, not controlling process intervals—proceeding to grinding before the putty has completely dried, causing sanding and peeling problems in the putty layer. Currently, mainstream GRG service providers in China, including Qinglong, Shiji Shangpin, and Shantaixin Industrial, have all established their own standardized process systems, and engineering parties can match the corresponding process standards according to their project grade requirements.

FAQ

1. How long does the total construction period for GRG component grinding and putty application generally take? For conventional projects executed according to standard procedures, the total grinding and putty application cycle for a single batch of components is 3-5 days, with slight adjustments based on the number of components and shape complexity.

2. Can ordinary putty be used for GRG component putty application? Not recommended. The adhesion and shrinkage rate of ordinary putty do not match the GRG substrate, and peeling and cracking problems are highly likely to occur later. GRG-specific gypsum-based putty material must be used.

3. What is the process difficulty of large-area GRG seamless treatment? The core difficulty lies in stress release at splice joints, which requires embedding crack-resistant fiberglass mesh during the putty application stage while controlling the thickness of each putty coat to avoid splice joint cracking during the drying shrinkage process.