Thinking Thursday - What you need to know about water-based film formation

During the process of film formation, which is the water evaporating from the coating film, both temperature and humidity in your environment are some of the factors that affect the formation of a water-based coating.  Application of a water-based product to a surface whose temperature is above or below 50 to 80 degrees F could cause the coating to have poor durability. 

Temperature is only one of the external factors affecting the proper cure time.  Also the relative humidity in your finish area at the time of application can either accelerate or retard the rate of drying.  If it’s low humidity, the final coat will have poor flow.  You will trap air bubbles which will result in an unsmooth slightly milky appearance.  If its high in humidity the coating will take more time to cure.  The coating will also not cure properly and the end result is it does not come to full hardness and durability. 

Air movement will also hurt or help film forming.  The applied surface should not be exposed to any strong drafts.  Too much rapid air and loss of water from the film will hurt the final appearance. 

In summary to use water-based products, ideally you want your room temperature to be 60 to 80 degrees F and the humidity to be around 40 to 65%.  Besides room temperature and humidity, the coating should also be at 60-80 degrees F before applying.  Anything outside of these numbers can affect the final coating.

Written by Dr. John Cox at Aqua Coat.