Tack-free Time (TFT)
Definition - What does Tack-free Time (TFT) mean?
Tack-free time (TFT) is a measure of a surface cure time during the application of a substance such as a coating or sealant. It is the time at which the coating is deemed to be properly adhered and capable of providing maximum protection to a surface without being disrupted or damaged.
A coating's tack-free time is important to note as it assists in scheduling and planning maintenance operations of large industrial units that must run concurrently. For example, a processing plant may have several pieces of equipment - pipes, tanks, and cyclones, amongst others, that must be protected from corrosion. During plant maintenance shut down, an understanding of the tack-free time as it pertains to each surface to be coated is vital to quickly resuming plant operations and enhancing output efficiency.
Corrosionpedia explains Tack-free Time (TFT)
Once a sealant reaches a state of sufficient resistance to damage due to contact or handling, the tack-free time has been reached. This applies to substances such as coatings and foams too. In test environments the tack-free time can be stated as simply the point where a film applied to a surface simply no longer feels sticky to the touch.