Secret of Chalk Resistant Paint
Secret to Selecting a Chalk Resistant Paint
Paint chalk is nothing more than broken down resin and pigment. A film of paint is basically like a very thick double decker sandwich (resin - pigment- resin - pigment - resin - pigment.......). A freshly painted surface has resin at the surface. You can prove this easily. After the paint dries, rub your finger across it. You will not have any pigment on your finger, it will be clean. However, do this same thing to a painted surface that has weathered outside for several years. Generally, you will get a film of pigment on your finger. The industry calls this chalk. The protective resin has broken down and left the pigment exposed. Thus, the key to chalk resistant paints is to purchase one that has quality resins and a high content of these resins. Since we already know that the resins are one of the most expensive ingredients in paint, you will probably pay a higher price for a chalk resistant paint. Beware of inexpensive paints and the claims they make!
To select a chalk resistant paint, you will need some very basic math skills. Most paint manufacturers list the contents of the paint on the side of each can. The contents are generally shown as two categories: PIGMENTS & VEHICLE. They are generally expressed as a percentage of the total volume. These categories are usually broken down again. The PIGMENTS will list various compounds which make up the pigments. The VEHICLE will list the amount of resin, any additives, and amount of solvent. Your mission is actually quite simple. To begin with, look for a paint that has a high vehicle percentage. Then, look to see if the resins comprise approximately 30 -35% of the total of the VEHICLE. If both of these values are high, you will be selecting a paint that has a very high total resin content. That is the secret.
Remember, the resin in the paint holds everything together. A high quality resin will resist breakdown. Also, the higher the ratio is between resin to pigment means that the pigment particles will be surrounded by that much more resin. This will make it harder for the pigment to get to the surface, where it appears as 'chalk'.