Individuals not involved in the production of hardware accessories may not be aware that the painting process for sofa legs involves numerous steps, with a high likelihood of issues arising during the painting process. These issues are typically caused by improper handling of the primer or base coat, inadequate control during the painting process, poor working conditions, and variations in the paint composition.

 

If problems are detected during the painting process, production can be halted, and immediate appropriate measures can be taken. Depending on the nature of the issue, it may be addressed after the painting process for the hardware accessories is complete.

 

 

Common Causes and Solutions for Defects in Hardware Accessories Surface Painting:

 

1. Color Seepage or Bleed-through During Processing

Color seepage or bleed-through refers to the failure of the color coat to fully cover the original paint color, or the color of old paint films or primer layers seeping through the topcoat, altering the color. Red and yellow paint layers are more prone to bleed-through.

 

Cause: Sedimentation of the color coat. After dilution, if the paint is not thoroughly stirred, pigments can settle at the bottom of the container, leading to an excessive resin content and lighter color in the sprayed paint.

 

Solution: For minor seepage, apply sufficient paint to cover; for severe cases, sand off the affected area and repaint.

 

2. Cracking of Body Filler or Mid-coat Primer During Processing

Cracks in the body filler or mid-coat primer areas can cause the topcoat to crack as well.

 

Cause: Applying body filler or mid-coat primer too thickly, without allowing adequate drying time between layers, resulting in a surface that appears dry but has a soft underlayer, leading to cracking. Apply in thin layers with sufficient drying time between each.

 

Solution: Thoroughly sand the cracked area, reapply body filler, and repaint with primer and topcoat, ensuring ample drying time between layers.

 

 

3. Fine Cracking During Processing

The paint surface loses its luster, and many fine cracks appear on the topcoat, resembling the dried mud cracks in a parched pond, often triangular, star-shaped, or irregularly radiating.

 

Cause: Excessively thick paint layers, causing stress concentration and cracking. Apply thinner coats and allow sufficient drying time between layers.

 

Solution: If fine cracks cannot be removed by sanding and polishing, sand the cracked area smooth, and if severe, strip down to the metal layer and repaint.

 

4. Linear Cracking During Processing

Obvious linear cracks penetrate the surface of the topcoat, with cracks being relatively parallel, commonly seen on black or other dark-colored paint surfaces.

 

Cause: Using coarse sandpaper during the metal surface treatment of sofa legs. Gradually use finer sandpaper for sanding.

 

Solution: Choose the correct mid-coat primer and topcoat. If cracks occur, sand the surface smooth with fine sandpaper, expose the inner coat, and repaint with the correct thinner.

 

 

5. Wrinkling During Processing

During painting or while the paint film dries, wrinkles or deformations appear on the surface of the topcoat, commonly seen in alkyd paint repair work.

 

Cause: Inappropriate drying methods leading to uneven paint drying. Avoid painting in workshops with inappropriate temperatures or significant temperature fluctuations.

 

Solution: After the paint is fully dried, remove the wrinkled surface and repaint.

 

6. Paint Surface Puckering During Processing

Also known as orange peel, it refers to the swelling of certain areas during painting or paint film drying, forming bumps.

 

Cause: Using the wrong thinner. Using a volatile paint thinner in enamel can promote the lifting of internal paint layers.

 

Solution: Sand the defective area smooth without breaking through, then repaint.

 

7. Paint Dripping During Processing

The coating becomes thicker in some areas, sagging due to gravity, commonly seen on surfaces that are placed vertically or sprayed vertically.

 

Cause: Incorrect use of thinners, such as slow-drying thinners or excessive amounts.

 

Solution: For minor sagging, sand the defective area after the paint dries, then wax and polish. For severe sagging, sand the area and repaint.

 

8. Wet Prints or Subsurface Wax Traces

The outline of the underlying contamination area is visible from the paint surface, or there are various shaped matte spots.

 

Cause: Inadequate cleaning of the underlying surface before painting, such as uncleaned grease or wax.

 

Solution: If wet prints are obvious, sand off the paint layer and repaint.

 

9. Water Stain Marks During Processing

White or yellow corroded spots appear on the paint surface, commonly seen on surfaces perpendicular to sunlight, such as the roof or hood.

 

Cause: Contact with water droplets, especially water with high mineral content, when the paint layer is not fully dried. The water droplets mix with the solvent in the paint and penetrate the surface, leaving water marks.

 

Solution: If there is a thick wax layer on the paint surface, clean thoroughly with a solvent and then polish. Choose a polisher based on the depth of the water stains, and repeat the cleaning and polishing process if severe. In extreme cases, sand with fine sandpaper and repaint.

 

10.Dust on Surface During Processing

After the topcoat is sprayed, foreign objects or dirt spots, such as dust or dirt trapped in the paint film, appear on the paint surface.

 

Cause: The painting workshop is unclean, such as the floor of the paint booth not having filter cotton laid, or the ceiling filter cotton not being replaced for a long time.

 

Solution: Keep the painting workshop clean, regularly replace the filter cotton in the paint booth, and strictly prohibit sanding body filler in the paint booth.