Valve Powder Coating

Surface Finish Options Overview

Characteristics of Valves

Valves typically have the following characteristics:

Thick and uneven walls

Irregular shapes

Rough surfaces

High thermal inertia, leading to slow temperature rise

Severe collisions during handling

Due to these characteristics, using conventional powder coatings often results in various issues. Our company has developed a specialized powder coating for valves through material selection and experimentation. This valve-specific powder coating not only offers the usual decorative appeal but also has the following outstanding features:

Excellent Adhesion, Impact Resistance, and Surface Scratch Resistance: The coating will not be damaged during normal handling and collisions of valves.

Low-Temperature Curing: The baking conditions are 160°C for 15-20 minutes or 180°C for 10 minutes. Compared to conventional powder coatings that require 180°C for 15-20 minutes, this coating improves spraying efficiency and saves energy.

High-Gloss Coating: The high-gloss powder coating for valves has excellent leveling properties, no sagging, good coverage, and excellent edge coverage. The coating thickness can be around 100 µm.

Defoaming for Cast Iron Valves: This coating effectively addresses defoaming issues for cast iron valves.

Improved Powder Transfer and Coverage: By adjusting the powder particle size and introducing new materials in the formulation, the Faraday cage effect is mitigated, resulting in better powder transfer and larger coating area.

Customizable Gloss and Texture: The coating can be tailored to meet customer requirements for various gloss levels and textures.

Powder and Coating Performance Results

Applications

Valves

Other industrial components with similar characteristics

FAQ

1. What is Powder Coating?

Powder coating is a dry finishing process used to apply a protective and decorative coating on metal or other surfaces. Instead of using liquid paint, fine powder particles (usually made of polyester, epoxy, or hybrid resins) are electrostatically charged and sprayed onto a conductive surface. The coated object is then baked in an oven, where the powder melts, flows, and cures into a smooth, durable finish.

Key features:

Durable, hard finish

Resistant to scratches, corrosion, and UV

Environmentally friendly (no VOCs)

2. Benefits of Powder Coating

Powder coating offers several advantages over traditional liquid painting:

Durability: Resistant to chipping, scratching, fading, and wear.

Corrosion Protection: Provides excellent protection against rust and chemicals.

Environmentally Friendly: No volatile organic compounds (VOCs) and minimal waste.

Efficiency: Overspray can be collected and reused, up to 99% material utilization.

Uniform Finish: Smooth, even coating without runs or drips.

Cost-Effective: Single-coat systems can achieve high film thickness, reducing labor and energy.

Aesthetic Variety: Wide range of colors, textures, and effects.

3. What Temperature to Cure Powder Coating

The curing temperature depends on the type of powder used:

Epoxy powder: ~160–200°C (320–392°F)

Polyester powder: ~180–210°C (356–410°F)

Hybrid (Epoxy-Polyester) powder: ~180–200°C (356–392°F)

Typical curing time: 10–20 minutes depending on thickness and oven type.

Always follow the powder manufacturer’s specifications for best results.

4. Process for Powder Coating

The powder coating process usually follows these steps:

Surface Preparation:

Clean the surface thoroughly (remove oil, grease, rust, or dirt)

Methods: chemical cleaning, sandblasting, or phosphating

Pre-Treatment:

Apply a conversion coating or primer if needed to improve adhesion

Powder Application:

Spray the powder using an electrostatic spray gun or fluidized bed

Curing:

Bake the coated object in an oven at the recommended temperature for the powder type

The powder melts and forms a continuous, smooth film

Cooling & Inspection:

Let the coated item cool

Inspect for defects, uniform coverage, and desired thickness

5. How to Spray Powder Coat

Equipment Needed:

Electrostatic spray gun

Compressed air supply

Powder feed hopper or container

Grounding of the object

Steps:

Ground the object: Ensures the charged powder is attracted to the surface.

Spray evenly: Hold the gun 6–12 inches from the surface, moving in smooth, overlapping strokes.

Apply sufficient powder: Ensure full coverage without excessive buildup.

Cure immediately: Transfer the sprayed item to the curing oven to fuse the powder into a solid coating.

Tips:

Maintain consistent speed and distance while spraying.

Use proper ventilation to reduce airborne powder accumulation.

Test a small area to check film thickness and color before full application.