Handling the Transition to Latex Paint

Handling the Transition to Latex Paint

Soon the mandate for low-VOC traffic paints is going to result in most of the pavement marking industry converting to latex and new technology traffic paints. You may have done so already. More likely, you will do so this year. Although it's not an easy process, by understanding how latex paint is different from alkyd paint you can minimize the headaches involved in the transition.

Latex paint dries when exposed to air or water.

New technology latex traffic paints dry as quickly, if not more quickly, than solvent-based paints. Latex paints are formulated to begin drying as soon as the pH of the paint is altered. In practice, this means that the paint will dry if exposed to air or water—in fact, latex traffic paint can dry under water.

In practice, this means that the only thing you want in your paint system is paint. If you need to flush your system, immediately put paint through the system to push out all the water. When you stop painting at the end of the day or over the weekend, fill the system and close it up. And avoid blowing your tanks, which introduces air into your paint lines and begins the drying process.

Once dry, latex paint is harder to remove since the cure and drying is not reversible because you are no longer using any solvent. Therefore, unlike alkyd paints, it cannot be easily re-dissolved by introducing more solvent.

Latex paint is incompatible with most metals except stainless steel.

Because of the chemistry of the emulsion in latex traffic paints, use of any metal other than stainless steel will cause an electro-magnetic reaction to occur. The paint will begin to set up, in much the same way that jello sets up in your refrigerator. The longer the paint is exposed to the metal, the harder it sets, until the line is completely plugged. These plugs will form anywhere the metal is present, resulting in multiple blockages throughout the paint system.

In some applications plastics and other materials can be used, but copper, brass, carbon steel and aluminum must be avoided.

Airless Systems usually work better.

The latest latex traffic paints have a high percentage of solids, so good quality paints can sometimes be a little harder to push than alkyd paints. For this reason, high-pressure airless systems seem to be made for latex paint, because the paint pumps easily handle even the thickest and heaviest of paints.

Also, keep in mind that latex paint begins drying instantly when exposed to air, so the atomizing air will contribute to paint drying at the guns and in the nozzles.

Latex paint does not mix with alkyd paint.

Latex and alkyd traffic paints are not compatible, so proper procedures must be followed to switch from alkyd to latex paint or vice versa. Our research and development team has developed a fool-proof four step process that has proved to be trouble-free. The same process is recommended for short and long-term storage as well. If you would like a copy of this procedure, contact Greg or Rob at 800-373-4016.