Selected Answers

From trevor neale of TF Warren Group on June 8, 2015:
Rodney White really has the correct answer to the ...read more Rodney White really has the correct answer to the question.Without the answers to the many questions, the chances of a successful repaint are very limited.

From Warren Brand of Chicago Corrosion Group on June 5, 2015:
 Tom, the material that I’m thinking of, whic ...read more  Tom, the material that I’m thinking of, which I have not personally vetted for bridges, but have specified elsewhere, has an anticipated service life in excess of 20 years when, of course, applied properly.

From Tom Schwerdt of Active Transportation Advocates on June 4, 2015:
Warren, if that's the same “soft” coating I'm thin ...read more Warren, if that's the same “soft” coating I'm thinking of, I heard some DOT guys from the Northeast extolling its virtues as a maintenance coating during their presentation. Upon further query, it turned out they were happy with a 5-year lifespan of the rehab, way too short for me.

From Jim Boyce of Insl-x Products Corp on May 29, 2015:
Although many systems could be applied, my initial ...read more Although many systems could be applied, my initial thought leans toward a "super low viscosity" epoxy, followed by an epoxy intermediate and a 2K urethane if long-term gloss and color are important.

From Rodney White of Independent Consultant on May 29, 2015:
It depends on answers to these questions. What is ...read more It depends on answers to these questions. What is the current coating system? What is the condition of the current system? Where is the tank situated? What are the prevailing weather conditions? What does the tank contain? Is there a chance of spillage? What type of prep is permitted? Will the tank be recoated by "sometime" painters, or will a professional company be engaged to do the work? What is the budget for the rehabilitation? What is the expected duty cycle once completed? There are far too many questions to be answered to arrive at a single, "pat" answer.

From rON Lewis of Corrosion Management Ltd on May 29, 2015:
The most common would be to overcoat whatever is t ...read more The most common would be to overcoat whatever is there with an alkyd of any type. Wrong, yes, but that is what most situations will receive. Epoxy is ok if the owner accepts this idea and the failing base coat accepts this. Let's go back to the original question about"rehabbing the exterior of above-ground storage tanks?" Depends on what's on the tank now, and what will be compatible, assuming the base coat is not removed before coating (re-coating). Now you need to be ready to read past midnight to find a coating solution that assures quality and economy. Let's face it, "In the common light of the matter, this is what keeps coating manufacturers and applicators in business (with or without the consultant's or owner's comments). Put it on, and for better or most often WORSE, the results remain about the same, no matter where the parking lot or highway is.

From Anthony Asmar of gulf silicone on May 29, 2015:
After preparing the surface to Sa2 1/2, apply two ...read more After preparing the surface to Sa2 1/2, apply two coats of zinc- rich primer at 125 microns DFT. This system will be sufficient  to protect the exterior shell of storage tank.

From Warren Brand of Chicago Corrosion Group on May 28, 2015:
Tough question. I would say the most common would ...read more Tough question. I would say the most common would be an epoxy base coat (with or without a zinc-rich primer) followed by a polyurethane top coat. However, there are many, many different systems out there that are one- and two-coat systems (saving labor costs by reducing an application step over a three-coat  system) and may have a higher total installed cost, but exceptional long service life and easy repairability. I want to stay away from product names, but there's also a system out there that is surface-tolerant and easy to apply (one coat) and has an exceptionally long service life. And maintenance is simple. However, it has a dull and lackluster appearance and remains "soft," thus being prone to damage from physical contact. Many other things must be considered as well, such as  the weather during application, condition of steel (new or existing), use of insulation (CUI issues), proximity to sensitive assets (parking lot or highway, requiring a dry-fall system), etc.