The Difference between Coil and Extrusion Coatings
Metal architecture around the world uses PVDF coatings to create head-turning facade designs.
Take the Anaheim Regional Transportation Center for example. The design team chose 70% PVDF Fluropon coatings in Silver to finish the exterior metal wall panels. The time-tested coatings help preserve the metal panels and create a sheen finish on the transportation hub.
This is just one example of PVDF coatings in our everyday lives. These coatings are used to finish metal building products such as fabricated panels, curtain wall and gutters. Different projects call for specific coating formulas to meet performance and design requirements.
Two main coating types are used to finish metal building products: coil and extrusion coatings.
The biggest difference between coil and extrusion coatings is how and when they are applied. Coil coatings are applied to coiled sheets of metal before it is formed, while extrusion coatings are spray applied after the aluminum extrusion has been formed.
This article explains the processes for coil and extrusion coatings, provides case studies for each and overviews typical end uses.
Example of Coil Coating Application - Metal Wall Panels
Example of Extrusion Coating Application - Window Systems
Coil Coating Application
The coil coating process starts with a flat metal sheet that is continuously fed into a coil coating line for nearly non-stop operation. Coating systems vary, but a three-step coating system will include a pre-treatment, a prime coat, and a top coat.
Once the process is complete, coils are ready to be formed into metal building products such as roofing panels or gutters.
Extrusion Coating Application
While coil coatings are applied to metal before it is formed, extrusion coatings are spray applied after metal has been formed. Shop-applied coatings are specially formulated to adhere to metal substrates and resist wear and tear throughout the manufacturing process.
The most common application of extrusion coatings is for projects that have to do with the arrangement and design of fenestrations in a surface of buildings, such as windows and doors. These types of metal building products include storefronts, curtain wall, skylight framing and exterior sun shades.
Architecture that Uses Extrusion Coatings
The stunning Absolute Towers are located in Mississauga, a neighbouring city to Toronto. The facade creation used extrusion panels finished with a PVDF coating in Pewter. The build was complex and required Sherwin-Williams to deliver batches of coating in various sizes—all with consistent formulas—to accommodate construction stages. All in all, coating the metal panels that clad the Absolute Towers took one and a half years, and it was worth it. Read more about the project in our case study.
Common applications for extrusion coatings are:
- Door frames
- Soffit & fascia
- Curtain wall
- Wall panels
Architecture that Uses Coil Coatings
An array of blues creates an aquatic-inspired design on the Lumberton Municipal Utility District. Metal wall panels clad the facade finished in a 70% PVDF resin-based coating. The colors used for this project include Deep Blue Sea, Arabian Blue, Slate Blue, Fashion Gray and Chromium Gray. Water management has never looked as good as it does on this Texas-based operations center. Read the full case study online.
Common applications for coil coatings are:
- Roof panels
- Wall panels
- Soffit & fascia
When it comes to the science behind coil and extrusion coatings, leave it to the lab to recommend the best formulas for a specific project at hand. The limitless combination of colors, finishes and special effects makes determining the appropriate coating choice an in-depth process. But the best place you can start is by browsing our online color library of more than 50,000 color swatches to find a hue or two that work best for your next project.