CUI is a common term used for corrosion under insulation. Corrosion on insulated tanks is a big threat to safety, productivity, and the bottom line. The right protective coating is crucial.

We will be comparing the EonCoat CUI Coating vs. Polymeric CUI Coatings in this note and we will break them down into 2 sections.

  1. Surface Preparation
  2. Coating Application

Surface Preparation

To prepare the surface for either of the two coatings it generally needs to be grit blasted, though if no old coating or mill scale is present, and rust has tightly adhered then EonCoat can be applied directly to the rust. The Polymeric CUI Coating Systems requires a more extensive blast than EonCoat. A near-white metal blast (SSPC 10) is required for polymeric coatings to properly adhere. Once the blast has been performed, the coating needs to be applied immediately before flash rust occurs, or a surface treatment must be applied to hold the blast. If it were to rain before the application is complete the entire process would have to start all over again.

EonCoat CUI only needs a surface prep of NACE 3 / SSPC-SP 6. It can also be applied directly to surface rust and does not require you to hold the blast. EonCoat CUI Coating can be applied in any humidity, even rain as long as it is not directly on the substrate. Less Abrasive used to sandblast surface & less clean up time.


Worker sandblasting a steel asset

Coating Application

For the Polymeric CUI Coating Systems holding the blast is crucial. The slightest bit of surface rust will compromise the coating. Multiple coats are required and usually long cure times. This translates to cost and long downtimes.

EonCoat CUI can be applied directly to surface rust and can be sprayed on. Unlike the Polymeric CUI Coating System. The actual application of the coatings is quicker. EonCoat CUI is also a one-coat system that cures in under 15 minutes. You have fewer coats to apply and you have much less time waiting around for it to cure. This leads to lower application costs and less downtime.


An insulated tank being prepared for service.

Summary of Polymeric CUI Coating Systems

Before EonCoat CUI was available. Companies used Polymeric CUI Coating Systems. If you’ve used traditional liquid polymeric CUI coating systems, you are familiar with their major limitations, namely:

  • They require extensive surface preparation and lengthy downtime to apply
  • They are susceptible to abrasion, temperature changes, and exposure to the elements
  • They need to be inspected and re-applied on a regular basis.

Why is EonCoat CUI Coating Better?

EonCoat reduces application time by about 50% thanks to its unique spray method and fast-curing properties. Once applied, EonCoat’s proprietary dual-layer formula eliminates the need for re-application. All you need is a single coat of EonCoat to protect your carbon steel assets for the life of the asset.

EonCoat CUI will reduce the time you spend maintaining your insulated tanks, cut down on corrosion monitoring and re-application costs, and maximize safety, protection, and uptime.

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