What WFT and DFT Mean

Wet-film thickness (WFT) is measured shortly after application while the coating is still wet. Dry-film thickness (DFT) is the cured coating thickness remaining after volatile material leaves the film.

Volume Solids Connect the Two

Product data sheets list volume solids and recommended thickness ranges. A simplified planning relationship is WFT = target DFT divided by the decimal volume-solids value. Field adjustments must follow the manufacturer’s current guidance and account for approved thinning.

Why One Reading Is Not Enough

Complex geometry, welds, edges, pitting and spray technique create variation. Inspection plans define gauge calibration, measurement frequency, spot readings, acceptance ranges and how inaccessible areas are handled.

Measure During Application

WFT checks help the applicator correct technique before the film cures. DFT readings document the completed coat or system. Readings should be tied to the asset area, coat, date and instrument.

Edges and Stripe Coats

Edges, welds, bolts and irregular surfaces are vulnerable to thin film. Specifications may require stripe coating before full-coat application to improve coverage at these details.

When Thickness Is Outside Range

Repairs depend on the product, cure state, location and owner requirements. Do not assume an extra coat solves every low reading or that a high reading is acceptable. Review the approved repair procedure and recoat window.