Carboline’s Technical Service team is often contacted by contractors, owners and specifiers looking for corrosion-resistant coating systems with high-performance characteristics for small carbon steel structures in exterior environments. These projects can range from replacing a section of pipe at a wastewater facility or industrial plant, to installing bollards for crash protection at a commercial property and replacing cleats on a dock at a marina.
For most of these projects, the coatings are applied in the shop environment, where long cure times can be problematic. Due to the small scale of these substrates, size can be a “nuisance” for the applicator to provide a high-performance coating system due to recoat limitations of specified products. After all, the last thing an applicator wants is a small job that requires several days to coat as a result of application parameters.
There are a variety of quick turn three-coat systems that are specifically designed to remedy this problem. When applied over a steel surface that has been commercial blast cleaned according to NACE’s SSPC-SP 6 standards, these coating systems will provide excellent long-term corrosion protection, as well as color and gloss retention properties.
| SYSTEM 1: Field-Applied Coating System | ||||
|---|---|---|---|---|
| Phase | Coating | DFT | Recoat at 75°F (23°C) | Recoat at 50°F (10°C) |
| Primer | Carbozinc 859 | 3-5 mils (75-125 µ) | 30 minutes | 2 hours |
| Intermediate | Carboguard 635 | 3-5 mils (75-125 µ) | 45 minutes | 1 hour |
| Finish | Carbothane OR Carboxane series |
Carbothane: 3-5 mils (75-125 µ) Carboxane: 3-5 mils (75-125 µ) |
Recoat window is only a concern if multiple coats are required to reach full hiding for field applications. If recoat of the finish is crucial, we recommend the use of System 2. | |
| SYSTEM 2: Shop-Applied Coating System | ||||
|---|---|---|---|---|
| Phase | Coating | DFT | Recoat at 75°F (23°C) | Recoat at 50°F (10°C) |
| Primer | Carbozinc 859 | 3-5 mils (75-125 µ) | 30 minutes | 2 hours |
| Intermediate | Carboguard 8922 | 1.5-2 mils (38-50 µ) | 5 minutes | 30 Minutes |
| Finish | Carbothane 8815 | 3-5 mils (75-125 µ) | Dry to Touch – 75°F (23°C): 25 minutes Dry to Handle – 75°F (23°C): 1.5 hours |
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These quick turn three-coat systems offer the option for a one-day application of a three-coat zinc/epoxy/urethane high-performance coating system on small steel structures. The field-applied coating system (System 1) uses a more typical approach with coatings that employs a quick recoat interval. In contrast, the shop-applied coating system (System 2) uses industrial coatings specifically designed for “wet-on-wet” applications typically found in the OEM industry. In addition, System 2 has been specifically tested for performance using these accelerated application times.
These advantages allow applicators to move units through their shops at a significantly quicker turnaround time. In the case of fieldwork, it also eliminates the need for applicators to return to the same job site for several days to paint a small substrate. Ultimately, this will increase productivity on project sites and throughput in shop applications by limiting the downtime associated with waiting for the coatings to cure.
