Epoxy vs Polyurethane Which Finish Should I Use

Image: The effects of chalking when a hand is rubbed against a degrading epoxy surface.

While both epoxies and polyurethanes can be used as finishes, they have differences when it comes to performance and function. Here is a comparison of epoxy vs. polyurethane to help you choose the best finish.

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Epoxy Coatings

While there are a number of different types of epoxy coatings available, in general, they consist of a two-part coating: one part resin, the other part hardener. The two components are thoroughly mixed in the required quantities and then applied to a surface and allowed to cure in accordance with the manufacturer’s instructions. Different formulas can produce different results, depending on the functional use required of the coating.

Epoxies are excellent in three key areas:

Adhesion

Epoxies are generally excellent at adhering to a well prepared surface.

Build and Thickness

Epoxies can generally be applied at high dry film thicknesses with no loss of performance.

Performance

Once the epoxy finish cures, you have a durable surface that has excellent electrical, thermal and chemical resistance.

The Downsides

However, you will find epoxies to be UV sensitive, which means exposure to sunlight will cause them to chalk.

Polyurethane Coatings

Although polyurethanes are generally of a lower dry film thickness than their epoxy counterparts, they do offer some unique advantages.

UV Stability

Polyurethanes offer excellent UV-resistance. Using them as a finish coat on top of an epoxy will protect the underlying epoxy from degrading.

Finishes

With polyurethanes, you also have the benefit of a broad range of aesthetic finishes, including satin, semi-gloss and high-gloss.

The best choice is not one over the other, but rather to use both together to achieve your desired results. Epoxy primers and build coats are perfect for adhering to a well prepared surface, while polyurethane topcoats offer the perfect enhanced protection and performance.

Here at KUE Group, we are committed to offering industry-leading steel surface preparation and coating and lining technology. To find out more about our services, please contact us today.

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