Application Apply it right. Protect it better.
Selecting the right coating is only part of the job. DFT, WFT, recoat interval, temperature, dew point and humidity all decide whether the specified system actually performs.
Selecting the right coating is only part of the job.
Application conditions, coating thickness, drying time and environmental conditions can all affect the final performance of a coating system.
01What is DFT?Dry Film Thickness
DFT stands for Dry Film Thickness. It is the thickness of a coating after it has dried or cured.
DFT is important because the specified coating thickness is usually linked to the expected protection and performance of the coating system.
DFT is normally checked using a suitable coating thickness gauge.
The goal is not the thickest coating. It is the correct coating thickness.
02What is WFT?Wet Film Thickness
WFT stands for Wet Film Thickness. It is the thickness of the coating immediately after application, before it dries or cures.
WFT can help applicators control the amount of coating being applied and achieve the required final DFT.
Why does it matter?
If too little coating is applied, the final dry film may be below specification. If too much is applied, excessive thickness may create application or curing problems.
WFT can be checked during application using a suitable wet film thickness gauge.
Control the wet film to achieve the right dry film.
03Why does recoat interval matter?Timing between coats matters
The recoat interval is the period between applying one coating layer and the next. Every coating product has recommended recoat conditions, which can vary depending on temperature, humidity, coating thickness and other factors.
What should you do?
Always follow the product’s specified minimum and maximum recoat intervals and consider the actual site conditions.
Good coating application is also about good timing.
04How does temperature affect painting?Temperature changes how coatings behave
Temperature can influence coating viscosity, drying, curing, solvent evaporation and application performance.
What should be considered?
Check:
Air Temperature · Surface Temperature · Product Temperature · Humidity · Dew Point
Always follow the coating manufacturer’s recommended application temperature range.
The right coating applied under the wrong conditions can still fail.
05What is dew point?Understanding condensation risk
The dew point is the temperature at which air becomes saturated with moisture and condensation can begin to form. For coating application, this is important because condensation on the substrate can interfere with coating adhesion and contribute to corrosion.
Why does it matter?
A steel surface may look dry but still be cold enough for moisture to condense on it. This can happen particularly when the surface temperature approaches the dew point.
What should be checked?
Before coating, assess:
Air Temperature · Surface Temperature · Relative Humidity · Dew Point
Many coating specifications require the substrate temperature to remain sufficiently above the dew point during application. A commonly used guideline is around 3°C above the dew point, but the coating specification and manufacturer’s requirements should always take priority.
If moisture can form on the surface, it is not ready for coating.
06How does humidity affect coating application?Moisture in the air can affect coating performance
Relative humidity (RH) describes the amount of moisture in the air relative to the maximum amount the air can hold at a particular temperature. High humidity can affect drying and curing, depending on the coating type.
What can happen?
High humidity may contribute to:
- Slower drying
- Slower curing
- Condensation on the substrate
- Poor appearance
- Reduced adhesion
- Blushing or other defects for certain coating types
Does every coating react the same way?
No. Water-based and solvent-based coatings can respond differently to humidity, and specific product requirements should always be followed.
What should be done?
Monitor:
Relative Humidity · Air Temperature · Surface Temperature · Dew Point
If conditions are outside the specified range, coating application may need to be delayed or controlled.
Good coating performance depends on controlling the environment, not just the product.
UNF application checkBefore you start painting
Surface
Is the substrate properly prepared and clean?
Temperature
Are the air, surface and product temperatures suitable?
Humidity
Is relative humidity within the specified range?
Dew point
Is the surface sufficiently above the dew point?
WFT
Is the correct wet film thickness being applied?
Recoat
Is the previous coat ready for recoating?
DFT
Has the final dry film thickness been checked?
The right product. The right conditions. The right application.
A coating system can only perform as intended when the surface, environment, application method and coating thickness are properly controlled.
Good coating performance is not just what you apply. It’s how, when and where you apply it.
Protecting What Matters. Built to Last.