ASTM D823-18(2022)

Overview

ASTM D823-18(2022) is a widely recognized international standard developed by ASTM International, covering the procedures for producing films of uniform thickness from paint, coatings, and related products on test panels. This standard ensures that the integrity and comparability of laboratory tests for coatings are maintained by providing detailed practices for consistent film application on various substrates.

Uniform film thickness is critical for assessing properties such as gloss, color, adhesion, and durability of coatings. The standard is essential for manufacturers, quality control professionals, and researchers working with coatings intended for spray applications, especially those involving metallic finishes where appearance properties are paramount.

Key Topics

ASTM D823-18(2022) outlines five primary practices for applying coatings to achieve uniform film thickness:

• Automated Spray Machine Application: Uses programmable machinery to move panels or spray guns at controlled speeds for consistent spray coverage.
• Motor-Driven Dip Coater Application: Employs automated devices to withdraw panels from coating baths at a set rate, suitable for flow-out coatings.
• Motor-Driven Blade Film Application: Utilizes a mechanized applicator blade moving at a constant rate for precise film formation.
• Hand-Held Spray Gun Application: Relies on skilled manual application using spray guns, commonly used in field and factory environments.
• Hand-Held Blade Film Application: Involves manually drawn applicator blades for flexibility in sample preparation.

The standard also references alternate techniques such as wire-wound drawdown bars, and provides detailed guidance on apparatus setup, panel preparation, application procedures, and key reporting requirements (e.g., thickness, environmental conditions, equipment parameters).

Applications

ASTM D823-18(2022) is valuable across a range of industries and laboratory settings focused on paints and coatings development, testing, and quality control. Typical applications include:

• Product Development: Ensures reproducible film thickness for accurate comparisons in R&D of new coatings, including metallic and appearance-dependent products.
• Quality Control: Facilitates reliable in-house or third-party validation of coatings' physical properties by minimizing film thickness variability.
• Conformance Testing: Enables repeatable panel preparation for gloss, color, and performance evaluations in compliance with industry standards.
• Comparative Performance Analysis: Supports consistent substrate conditioning and film formation for side-by-side comparison of different formulations or manufacturing processes.

These practices help address challenges such as orange peel or spray wave effects, and are especially crucial when appearance and performance must be closely matched to customer or regulatory requirements.

Related Standards

ASTM D823-18(2022) is closely aligned with several other key ASTM standards used in the coatings and materials industry:

• ASTM D1005: Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
• ASTM D1212: Test Methods for Measurement of Wet Film Thickness of Organic Coatings
• ASTM D3924: Specification for Standard Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials
• ASTM D4147: Practice for Applying Coil Coatings Using Wire-Wound Drawdown Bars
• ASTM D4285: Test Method for Indicating Oil or Water in Compressed Air
• ASTM D4414: Practice for Measurement of Wet Film Thickness by Notch Gages
• ASTM D7091: Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings

Compliance with ASTM D823-18(2022) helps organizations demonstrate commitment to quality, reproducibility, and international best practices in coatings testing. Using referenced standards alongside D823 facilitates comprehensive evaluation and documentation for regulatory or customer acceptance.

Keywords: ASTM D823, uniform film thickness, paint testing, coatings quality control, test panels, spray application, dip coater, blade applicator, laboratory standards, coatings industry.