Problem Solving Forum
July 12 - July 16, 2021
What is the recommended coating system and procedure for repairing deteriorated inorganic zinc/epoxy/polyurethane 3-coat systems? Does the repair system or procedure vary with the degree of deterioration and if so, how?
Selected Answers
From
Parthasaradhi Napa of Severnglocon india ltd on
July 20, 2021:
First should be informed and consideration in pain ...read more
First should be informed and consideration in paint manufacturers,they can decide the procedure.
From
Neil Pittman of Lake Superior Consulting on
July 14, 2021:
In general, the best system to replace a deteriora ...read more
In general, the best system to replace a deteriorating coating system is what was applied originally. This may not follow that rule, though. If the original coating (parent system) has had a good service life (i.e. it was the right coating system for the service environment) then in this case it may be more appropriate to use an organic zinc primer with an epoxy midcoat and a polyurethane topcoat. It is common to use organic zinc primers in repair situations as organic zinc is generally more tolerant of application environment, and ties into organic zinc well. There is no hard and fast rule as to what percentage of the substrate has deteriorating coating before you move to using an organic zinc primer, but if I would call it a "repair" and not a "recoat" I'd specify organic zinc.
If the original coating manufacturer is known, then a recommendation from them on which of their organic zinc primers to use will be helpful.