ASTM D823-18 Standard Practices for Producing Films: Essential Guidelines for Paint and Coating Thickness Testing

[vc_row][vc_column][vc_column_text css=””]Paint testing requires precise methods to evaluate quality and performance. The ASTM D823-18 standard practices provide essential guidelines for creating uniform thickness films of paint and coatings on test panels. These practices help you achieve consistent, reliable results when testing paint properties, durability, and appearance.

The current version of these practices, approved in June 2022, builds on decades of paint testing expertise dating back to 1945. When you need to evaluate paint or coating performance, following standardized methods ensures your test results are valid and comparable across different laboratories.

Key Takeaways

• Paint films must have uniform thickness on test panels to get accurate results
• Standardized testing methods ensure consistent quality control across the industry
• The D823-18 practices cover everything from panel preparation to proper application techniques

Scope and Applicability

ASTM D823-18 provides five different practices for creating films of uniform thickness on test panels. You can use these methods when testing paints, coatings, and similar products.

The practices include:

• Practice A: Automated spray machine application
• Practice B: Motor-driven dip coater application
• Practice C: Motor-driven blade film application
• Practice D: Hand-held spray gun application

Spray applications are particularly important when evaluating metallic coatings for properties like gloss and color. These methods help you achieve consistent results in both factory and field testing.

Each practice gives you specific instructions to create uniform coating thickness. This helps ensure your test results are reliable and repeatable.

These methods follow international standards established by ASTM International. The practices have been refined since their original approval in 1945.

You should choose the practice that best matches your coating type and application method. For spray coatings, Practice A or D will give you the most accurate results.

Test Panel Preparation

ASTM D823 requires proper test panel preparation to ensure accurate and consistent coating film thickness measurements.

Clean your test panels thoroughly with appropriate solvents to remove all traces of oil, grease, and contaminants. Use a lint-free cloth for cleaning and allow panels to dry completely.

For metal panels, you may need to apply a surface treatment or primer according to the coating manufacturer’s specifications. This helps with proper adhesion and uniform film formation.

Position your panels on a level surface before applying any coatings. The panels must be perfectly horizontal to achieve uniform thickness distribution.

Required Panel Conditions:

• Clean and dry surface
• Free from defects or damage
• Proper temperature (typically room temperature)
• Level positioning
• Correct dimensions for test method

Check the coating thickness measuring device calibration before starting. You can use either metric (SI) or imperial units, but maintain consistency throughout your testing process.

Store prepared panels in a controlled environment until you’re ready to apply the coating. Avoid touching the test surface with bare hands after cleaning.

Film Application Techniques

ASTM D823-18 specifies five distinct methods for applying uniform coating films to test panels. Each technique offers unique advantages for achieving precise film thickness control.

Motor-Driven Dip Coater Application

The motor-driven dip coater provides consistent coating thickness through mechanical immersion and withdrawal. You’ll need to set the withdrawal speed between 6 and 12 inches per minute for optimal results.

The panel must be clean and positioned vertically in the dip coater. Temperature control is essential – maintain coating materials at 73.5°F ± 3.5°F.

Key benefits include:

• Excellent thickness uniformity
• Minimal operator variation
• Suitable for high-volume testing

Hand-Held Spray Gun Application

Spray application requires careful control of distance, pressure, and speed. Keep the spray gun 6-8 inches from the panel surface at a 90-degree angle.

Essential parameters:

• Air pressure: 40-60 psi
• Gun speed: Consistent pace
• Pattern overlap: 50%

Make multiple passes for desired thickness. Allow each pass to flash off before applying the next coat.

Automated Spray Machine Application

Automated spray systems deliver the highest consistency in film application. The machine controls speed, distance, and pattern automatically.

Programming requirements:

• Spray pattern width
• Gun traverse speed
• Number of passes
• Flash-off time

This method reduces human error and provides excellent reproducibility between test panels.

Motor-Driven Blade Film Application

The blade applicator creates precise film thickness through mechanical drawing. Set the gap height to your target film thickness plus 50%.

Critical factors:

• Draw-down speed
• Blade pressure
• Material viscosity
• Surface levelness

Clean the blade between applications to prevent thickness variations.

Hand-Held Blade Film Application

Manual blade application uses draw-down bars or applicators. Select the appropriate gap clearance for your target film thickness.

Tips for success:

• Use steady pressure
• Maintain constant speed
• Draw in one direction only
• Keep blade angle at 45 degrees

This method works well for quick tests but requires practice for consistent results.

Tools and Equipment

Proper tools help create uniform paint and coating thickness on test panels. Precise application methods ensure consistent results for quality testing and evaluation.

Wire-Wound Drawdown Bars

Wire-wound drawdown bars create precise film thickness for paint and coating applications. You can select bars with different wire diameters to control coating depth from 0.5 to 10 mils.

The bars consist of stainless steel wire wrapped tightly around a steel rod. The space between wire coils determines how much coating passes underneath during application.

To use these bars effectively, you must maintain a steady application speed of about 6 inches per second. Clean the bars thoroughly after each use to prevent coating buildup.

Automatic Spray Equipment

Automatic spray systems provide consistent coating application across test panels. You can adjust spray pressure, distance, and speed to achieve your desired film thickness.

The equipment includes pressure regulators, fluid tips, and automated movement controls. Set spray gun height between 6-12 inches from the panel surface for optimal coverage.

Digital controls let you save specific settings for different coating materials. This ensures reproducible results across multiple test panels.

Regular maintenance of spray tips and filters prevents clogging and ensures uniform application. Clean all equipment components after each use with appropriate solvents.

Quality Control and Appearance

The uniform thickness of paint films directly affects their appearance and performance. You can achieve optimal results by maintaining strict quality control during application.

When applying paint films to test panels, your coating thickness must stay within ±10% of the specified value. ASTM D823 practices help ensure consistent film formation across test surfaces.

You should inspect the dried film for these visual defects:

• Orange peel texture
• Runs or sags
• Uneven coverage
• Bubbles or pinholes
• Surface irregularities

The optical properties of your paint film depend heavily on proper thickness control. A uniform film will display consistent gloss, color, and hiding power across the entire surface.

Monitor the application conditions carefully:

• Room temperature: 23°C ± 2°C
• Relative humidity: 50% ± 5%
• Clean, dust-free environment
• Level application surface

Your finished test panels need smooth, even coverage without visible defects. Check the surface under good lighting from multiple angles to spot any inconsistencies.

Regular calibration of your application equipment helps maintain precise film thickness control. Clean equipment thoroughly between uses to prevent contamination.

Safety and Environmental Considerations

When working with paints and coatings, you must follow proper safety protocols to protect yourself and the environment. Always wear appropriate personal protective equipment (PPE), including safety goggles, gloves, and respiratory protection.

Ensure your workspace has adequate ventilation and safety measures in place. This helps control exposure to volatile organic compounds (VOCs) and other potentially harmful substances.

Keep a spill kit nearby and know the proper procedures for handling chemical spills. Store all materials according to manufacturer guidelines and local regulations.

Dispose of waste materials properly. Many paints and coatings are considered hazardous waste and need special handling. Check your local regulations for proper disposal methods.

Clean your equipment and work area with appropriate cleaning agents. Prevent paint and coating materials from entering drains or water systems.

Keep safety data sheets (SDS) readily available for all materials you use. These documents contain important safety information and emergency procedures.

Key Safety Items:

• Protective eyewear
• Chemical-resistant gloves
• Proper respiratory protection
• Protective clothing
• Emergency eyewash station
• First aid kit

Never eat, drink, or smoke while handling coating materials. If you experience dizziness, headaches, or other symptoms, leave the area immediately and seek fresh air.

Global Standards and Trade

ASTM D823-18 plays a vital role in international trade by providing standardized testing methods for paint and coating thickness. When you follow these standards, you ensure your products meet global quality requirements.

The standard helps eliminate technical barriers to trade by creating a common language for paint testing across borders. Your products can more easily enter new markets when they comply with internationally recognized standards.

Testing labs around the world use these practices to verify coating thickness uniformity. This creates consistency whether you’re testing samples in Asia, Europe, or North America.

Այն five standardized practices for film application give you multiple options that align with different regional requirements and equipment availability. This flexibility helps manufacturers adapt while maintaining compliance.

Your quality control process becomes more reliable when using these globally accepted methods. Trade partners trust results from ASTM standards because they’re developed through international consensus.

Remember to check if your target markets specifically reference ASTM D823 in their import requirements. Some regions may have additional or alternative standards you need to follow.

Frequently Asked Questions

ASTM D823-18 provides five distinct practices for creating uniform coating films on test panels, including automated spray, dip coating, and manual methods. Each practice requires specific equipment, safety measures, and environmental controls to achieve reliable results.

How can I properly apply coatings to test panels in accordance with ASTM D823-18?

You must first select the appropriate application method from the five available practices based on your coating type and intended use. Automatic Film Application and Automated spray application work best for evaluating metallic coatings and appearance properties.

Clean and prepare your test panels according to the standard specifications. Maintain consistent application speed and distance when spraying.

Check the coating viscosity and adjust it to match the manufacturer’s recommendations before application.

What equipment is required to perform the practices outlined in ASTM D823-18?

For automated spray application, you need a spray booth, automated spray machine, and air pressure regulators.

Այն dip coating method requires a motor-driven dip coater and timing controls.

You’ll need temperature and humidity monitoring devices for all methods to ensure proper environmental conditions.

Can you explain the key differences between ASTM D823-18 and ASTM D3258?

ASTM D823-18 focuses specifically on creating uniform thickness films for testing purposes using five distinct application methods.

ASTM D3258 deals with porosity testing and substrate evaluation rather than film application techniques.

What are the safety considerations when conducting film application as per ASTM D823-18?

Use proper ventilation systems and wear appropriate personal protective equipment, including respirators and chemical-resistant gloves.

Keep fire extinguishers nearby when working with flammable coatings.

Monitor air quality and maintain proper airflow in the application area.

How do the film thickness requirements differ for various coatings in ASTM D823-18?

Film thickness requirements vary based on the coating type and its intended end-use. Follow the coating manufacturer’s recommended thickness specifications.

Measure wet film thickness during application using appropriate gauges. Check dry film thickness after curing.

What are the recommended conditions for curing and drying coatings under ASTM D823-18?

Maintain temperature between 23°C ± 2°C (73.5°F ± 3.5°F) during the curing process.

Keep relative humidity at 50% ± 5% throughout the drying period.

Allow adequate air circulation while avoiding direct air flow onto the coating surface.[/vc_column_text][/vc_column][/vc_row]