PPG’s Spectracron SEP Primer Reduces Flash Times

Cuts drying while also maintaining corrosion resistance.


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Watching paint dry just got more exciting, especially if you coat in the agriculture, construction and heavy equipment industries.

PPG’s Spectracron SEP wet-on-wet epoxy primer—designed specifically for heavy-duty OEMs—is formulated to reduce flash times (drying times) to only two minutes. Industry-typical flash times are between 10 and 45 minutes, and there is a growing need for flash times below five minutes to increase throughput and decrease paint costs. Shorter flash times means lower costs, simplified stock and reduced inventory.

“There is a need to shorten these flash times much below 10 minutes. We’re starting to see a lot more of five minutes, two minutes,” Scott Laney, PPG’s liquid coatings product manager, says. “You have to create a product to fit the specific application conditions of the facility. That was why this product is innovative; it had a very short wet-on-wet flash time.”

But PPG had to also consider product performance, as well as the selection of raw materials that must be incorporated. The primer was formulated with performance in mind, Laney says,  with the goal of increasing production rates without sacrificing the quality of the finish. This primer had to meet the requirements of the applicator, while also maintaining performance.


Application Method

Conventional air, airless, or air-assisted spray

Flash Time

5 minutes

Time at Temp

30 minutes

Oven Temp

180° F


22–28 sec # 2 EZ Zahn Cup (77°F)

Dry Film Per Coat

1.5–2.0 mils

Shelf Life

12 months (closed container)

Solids % by Weight

59.2 +/- 2 %

Solids % by Vol

41.4 +/- 2 %


“Keeping the corrosion resistance is always the key,” Laney says. “Though you try to formulate the product to meet these application conditions, you also have to maintain the performance of the product that you’re trying to improve. You can’t fit the application with detrimental effects to performance.”

PPG’s Spectracron SEP is also designed to provide a finish without solvent-pop or soak-in issues. Typically, reduced flash times cause “pimpling” in the finish, because the solvents do not escape from the film prior to the second coat.

“You overcome this by using different formulations and techniques to eliminate, avoid and improve this pop-resistance and level of sag,” Laney says. “To get sufficient coverage of a primer or topcoat, you need a good product with robust application that provides good sag and pop-resistance at a very high film thickness.”


Photograph courtesy of PPG.

Spectracron SEP also includes a number of operational benefits, including reduced VOC emissions without the use of exempt solvents, which are a list of solvents that coatings companies allow to be put into the paint that don’t have any effect on VOCs. The primer is available in green or buff colors, as well as specialty colors for specific applications.

Originally published in the November 2015 issue.