Knowledge Base

Cure times

The time taken for StarFix adhesives, coatings and sealers to cure

Every product in the StarFix range has been formulated to provide the ideal balance between working time and rapid strength development, helping installers work efficiently without compromising long-term performance. Depending on the product, cure characteristics such as liquid working time, skin formation, tack-free time, through-cure and full cure have been carefully engineered to suit their intended application.

The guide below provides typical cure times for each StarFix product under standard laboratory conditions of 20°C and 40–60% relative humidity. These values should be used as a general reference, as actual cure rates will vary depending on substrate temperature, ambient temperature, humidity, film thickness and ventilation.

Our technical team is always available to provide advice where installation conditions fall outside normal operating environments, ensuring you achieve the optimum performance from every StarFix product.

StarFix adhesives and extreme temperature/humidity:

StarFix adhesives cure by reacting with atmospheric moisture. Under normal conditions, increasing temperature and relative humidity will accelerate the curing process. However, as ambient and substrate temperatures reach 30°C or above, the curing behavior may become significantly slower. Whilst these conditions are not common in the UK, the frequency of above average temperatures is increasing.

❶ At temperatures in excess of 30°C, the time taken to reach full cure can be significantly increased.
❷ At temperatures in excess of 30°C, the viscosity of the adhesive can drop below the minimum specification.

At elevated temperatures, moisture present on the pedestal adhesive surface can react very rapidly, causing the formation of a partially cured surface skin. This skin can restrict the further diffusion of atmospheric moisture into the bulk of the adhesive, reducing the rate at which the underlying material cures. In addition, high temperatures can lower the relative humidity immediately adjacent to warm substrates, reducing the amount of moisture available to sustain the curing reaction.

As a result, although the pedestal adhesive may become surface dry relatively quickly, the development of full cure and the expected mechanical properties (T42. Swing-bag test) may take longer than would normally be expected. For optimum performance, application is recommended at substrate and ambient temperatures between 5°C and 25°C with adequate ventilation and a relative humidity of 40–70%. Where temperatures exceed 30°C, additional curing time should be allowed before testing or the bonded pedestals are placed into service. If the adhesive has been used in the described, extreme temperature/humidity conditions and has not reached full cure after 48 hours then a fine mist of water can be sprayed onto the adhesive surface to increase the rate of cure.