Dry Film Thickness Testing

Dry Film Thickness Testing

Dry film thickness (DFT) testing measures the thickness of coatings applied to metal surfaces. Proper coating thickness is essential for corrosion protection, appearance, and performance. DFT testing ensures that coatings meet specified requirements without being too thin (inadequate protection) or too thick (waste and potential failure).

Service Details

Dry film thickness is measured after the coating has fully cured. The measurement method depends on the type of substrate (ferrous or non-ferrous) and the coating material.

Dry Film Thickness Testing Methods

• Magnetic Method – Used for non-magnetic coatings (paint, plastic, anodizing) on ferrous (magnetic) substrates. A permanent magnet or electromagnetic probe measures the attractive force or magnetic flux density, which changes with coating thickness.

• Eddy Current Method – Used for non-conductive coatings on non-ferrous (non-magnetic) conductive substrates. A probe generates a high-frequency magnetic field that induces eddy currents in the substrate. The coating thickness affects the eddy current flow.

• Ultrasonic Method – Used for thick or multiple-layer coatings on any substrate. Sound waves reflect from coating-substrate interfaces.

Common Standards

• SSPC-PA 2 – Coating thickness measurement on steel substrates

• ISO 19840 – Coating thickness measurement on rough surfaces

• ASTM D7091 – Magnetic and eddy current methods

• ISO 2808 – Various methods for paint and varnish thickness

Applications

Dry film thickness testing is used in:

• Pipeline and structural steel coating inspection

• Marine and shipbuilding coating verification

• Storage tank and pressure vessel lining inspection

• Automotive and aerospace coating quality control

• Bridge and infrastructure coating assessment

Our Dry Film Thickness Testing Capabilities

Our facility is equipped with:

• Digital magnetic DFT gauges for ferrous substrates

• Eddy current DFT gauges for non-ferrous substrates

• Dual-technology gauges (magnetic and eddy current)

• High-range gauges for thick coatings (up to 5 mm)

• Statistical reporting and data logging

We perform DFT testing on:

• Epoxy, polyurethane, and other paint coatings

• Galvanizing and zinc-rich coatings

• Powder coatings

• Anodizing and plating

• Tank linings and pipe coatings

All dry film thickness testing is performed following SSPC, ISO, and ASTM standards.

Contact Us

Phone: +91-9811159123

Email: info@mayankndtengg.com