Feeling hot and bothered? It’s not always the temperature or humidity, it’s the dew point. Not only does it affect people, but it also affects paint!
So, what is dew point and what does it do?
Dew point is the temperature at which the air becomes saturated with water vapour, causing precipitation to occur in for of, condensation, fog dew, etc. it is the temperature at which the air can no longer retain the moisture it contains, and the excess moisture condenses into liquid form.
For most of us, in warm sultry weather, it’s not unusual to feel hot and bothered, sticky, feeling hotter for longer. this is because the present atmospheric moisture in hot temperatures can slow the body’s ability to cool down.
For painters and companies who rely on coatings in their manufacturing process, the dew point can present a real headache.
Dew point can affect the way paint cures and dries. When painting below dew point, moisture can condense on the surface while it is still drying. This leads to a surface defects such as a milky, patchy appearance once cured, blistering, delamination, loss of adhesion, or it could even prevent the paint from curing at all.
To avoid dew point related issues with paint, there is several things that can be done. For most coatings it is recommended to paint at least 3 degrees above dew point.
It is important to ensure the surface being painted and the surrounding air is a temperature above dew point, when in an enclosed space use dehumidifiers and heaters to control the environment and maintain a constant temperature and humidity level.
To avoid issues related to dew point and paint, it is important to ensure that the surface being painted and the air surrounding it are at a temperature above the dew point. This can be achieved by controlling the environment in which the paint is applied, such as by using dehumidifiers or heaters to maintain a consistent temperature and humidity level.
Examples of dew point:
#1.
– Temp: 35C
– Relative Humidity: 95%
– Dew Point: 33
It is not recommended to paint in these conditions.
#2.
– Temp: 20C
– Relative Humidity: 75%
– Dew point: 13
It is ok to paint in these conditions.
#3.
– Temp: 10C
– Relative Humidity: 80%
– Dew point: 5
It is ok to paint in these conditions.
Whilst it may not always be possible to paint 3 degrees above the dew point, specific coatings can be used for these applications. Consult with the team at A&I Coatings, 1800 819 585, to determine what is the best course of action or products to use in these circumstances.
