Drying Guide: Touch Dry Hard Dry Full Cure
The coatings industry uses a variety of terms to describe the ‘drying’ & ‘curing’ process of paints, sealants & inks. It is important to understand the difference between the terms ‘Touch Dry’, ‘Hard Dry’ & ‘Full Cure’, that are often quoted in our literature.
It is important to understand the difference between the terms ‘Touch Dry’, ‘Hard Dry’ & ‘Full Cure’, that are often quoted in our literature. These times have been determined in the laboratory using a typical dry film thickness, the ambient temperature quoted in the relevant product data sheet, and the appropriate test method (normally ISO).
The surface drying state of a coating when Ballotini (small glass spheres) can be lightly brushed away without damaging the surface of the coating (ISO 1517 – 1973)
The condition of the film in which it is dry throughout its thickness (ISO 9117-1990)
In practice, the coating has reached a stage of its drying process where it will withstand pressure and can be worked on and machined, if required.
The coating has reached its full chemical / mechanical properties and will resist and perform as per the properties outlined in the relevant product data sheet / specification document
It is important to note that the drying & curing times achieved in practice may show some slight fluctuations, particularly when climatic conditions (substrate temperature & the ambient air temperature) vary and especially when there are variations in the film thickness applied.