The Max Recoat Window Is Real Too

The Wet Edge, No. 006. Short field notes for coating crews.

Most crews watch the minimum recoat time. It's the maximum that gets forgotten, usually because the job got pushed.

A lot of two-component coatings, epoxies especially, bond best to the next coat while the first one is still curing. Wait too long and the surface gets hard and slick enough that the next coat sits on top instead of biting in. That's why data sheets list a maximum recoat, and why many of them tell you to abrade before recoating if you miss it.

The window varies a lot from product to product. Tnemec's Series N69 epoxy, for example, calls for scarifying or an epoxy tie-coat after 60 days. Other products close much sooner, so the window from your last job doesn't carry over.

Why it matters: intercoat adhesion failures don't show up at punch list. They show up months later when the topcoat lets go in sheets, and that's a warranty conversation nobody wants. A scuff-sanding pass on a missed window costs a day. Stripping a failed topcoat costs a lot more.

The practical move: when the schedule slips, pull the data sheet for the coat that's already on and write the max recoat date on the job board. If you're past it, abrade per the data sheet, or call the manufacturer before you put on another coat.

Bottom line

The max recoat window is as real as the minimum. Miss it and the next coat may not bond, so abrade per the data sheet before you recoat.

Further reading: Tnemec Series N69 Hi-Build Epoxoline II.

Talk to a consultant. Questions on a job? Atlantic Coating Consultants supports contractors in PA, NJ, DE, MD, DC, WV and OH with product recommendations, field support and crew training. Call 484-644-5303 or email atlantic@tnemec.com.