Office Chair Base Polishing

Polishing the base of an office chair requires following standardized steps to ensure a flat surface and protect the material properties. The specific operations are as follows:

I. Preliminary Preparation and Cleaning

Thoroughly clean the base surface before polishing:

1. Remove Impurities: Use a stiff brush or scraper to eliminate dust, oil stains, old, cracked coatings, and loose burrs. This prevents impurities from scratching the workpiece or clogging the sandpaper during the polishing process.
2. Clean and Dry: Wipe the surface repeatedly with a damp, wrung-out cloth to ensure no cleaning agent residue remains. Then, place it in a well-ventilated area to dry completely. If the wood moisture content is too high, burrs may form during polishing, affecting subsequent treatment results.

II. Tool and Sandpaper Selection

Choose sandpaper grits based on the base material (taking wood as an example):

1. Rough Polishing Stage: Use 80 - 120 grit sandpaper to focus on removing old paint layers, raised burrs, or severe scratches. If the old paint is thick, first use 80 grit sandpaper to quickly polish perpendicular to the wood grain, then switch to 120 grit for fine polishing along the grain.
2. Medium Polishing Stage: Switch to 240 - 320 grit sandpaper to smooth out the marks left by rough polishing and achieve an initial flat surface. Control the force during this stage to avoid excessive polishing that thins the wood.
3. Fine Polishing Stage: Use 400 - 600 grit sandpaper for fine polishing to enhance surface smoothness. For a higher gloss, add 800 - 1000 grit sandpaper for further treatment.
   Simplified Plan: You can also directly prepare three types of sandpaper: 80 grit (for removing old paint), 240 grit (for refinement), and 400 grit (for polishing), and polish step by step in order.

III. Polishing Operation Techniques

1. Polishing Along the Grain: Always operate along the wood grain direction. Polishing horizontally will leave hard-to-clean scratches, affecting the coating's adhesion. For example, when polishing worn areas on chair legs, lightly polish in a circular motion along the grain with uniform force, avoiding prolonged停留 (lingering) in local areas to prevent depressions.
2. Curved Surface Handling: When encountering curved parts (such as chair leg corners), wrap the sandpaper around a small wooden block or rubber block and polish along the contour. This ensures a smooth and natural curve and avoids an uneven surface caused by direct hand pressure.
3. Zonal Polishing: First, handle large flat areas, then deal with details such as edges and corners. This ensures consistent overall flatness.

IV. Final Treatment and Protection

1. Clean the Surface: Wipe off the dust with a clean soft cloth or microfiber cloth. If dust remains, it will affect the adhesion and gloss of subsequent coatings.
2. Coating Protection: Apply a thin layer of wood wax oil or varnish. Wood wax oil can penetrate the wood to form a protective layer, while varnish provides stronger wear resistance and brightens the color.
3. Safety Protection: Wear a dust mask throughout the polishing process and keep the room well-ventilated. Avoid inhaling dust, which can cause respiratory diseases.