8 January 2025

Application of a hard coat system to the tanks of a floating sheerleg

Treatment of voids in floating sheerleg with nC Corrosion Passivator direct to rust coating system

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Date:

11-2024

Location project:

Rotterdam

Client:

Maritime service provider

Application:

Floating sheerleg

Product(s):

nC Corrosion Passivator Hard Coat System

Preparation:

High-pressure washing

Application method:

Spraying

During weeks 47-50 of 2024, six voids of a floating sheerleg were treated with a hard coat system specifically developed for direct application to rust, consisting of:

nC Corrosion Passivator Primer WET
nC Protect EP Undercoat
nC Protect EP Heavy Duty

Project Details – Floating sheerleg

Treated surface: 6 voids of the floating sheerleg.
Surface area: 1.550
Project duration: 3 weeks

Direct - to - rust application coating system nC Corrosion Passivator

Pre-Treatment of the voids of the floating sheerleg

Using 500 bar high-pressure washing is essential to thoroughly clean the tanks and remove any loose coating and loose rust. It is not necessary to dry the surface with heaters after high pressure washing.

To minimize project time, a direct-over-rust solution was chosen that can be applied to damp, corroded surfaces, reducing the waiting time after high-pressure washing. The most suitable passivator for this is the nC Corrosie Passivator – Primer WET. It is free from harmful solvents and, through capillary action, penetrates deeper into any existing rust or pores in the steel.

Application Process – Hard Coat – nC Corrosion Passivator

After the pretreatment procedures, the coating system can be applied directly to the (clean) corroded surface. In total 3 layers of coating have been applied:

Layer 1: nC Corrosion Passivator Primer WET
Layer 2: nC Protect EP Undercoat
Layer 3: nC Protect EP Heavy Duty

Direct - to - rust application of nC Corrosion Passivator Coating system

nC Corrosion Passivator WET

A corrosion passivator developed for consistently wet or damp surfaces. It should only be applied to metal surfaces that are moist, wet, corroded, or have flash rust. This product can be directly applied to rust, effectively stopping the corrosion process. It creates a stable surface that can be coated with any one- or two-component metal primers or topcoats.

nC Protect EP Undercoat

An epoxy-based primer with a combination of anticorrosive pigments, specifically developed to be compatible with nC Corrosion Passivator Primer.

nC Protect EP Heavy Duty

High Solid epoxy-based topcoat, designed for enhanced durability and corrosion protection.

This direct-over-rust system meets the requirements for corrosion category C5 (medium) according to ISO 12944-6.

Results – Treatment of the voids of the Floating Sheerleg

As shown in the pictures, the voids are now protected with a 4-layer coating system. On December 13, 2024, an extensive coating thickness measurement was conducted in the voids by nC Protect to confirm project completion. Overall, the coating has been applied cleanly and provides uniform coverage, which will result in a long term protection of the voids against corrosion.

nC Protect - nC Corrosion Passivator - Treatment corrosion in tanks

Conclusion – Tank conservation Floating Sheerleg

Traditional tank conservation involves the time-consuming pre-treatment of tanks through abrasive blasting. The use of Corrosion Passivator Primer WET enabled a direct-over-rust coating system that meets ISO C5 (Medium) standards. This approach reduced the project duration to just 3 weeks, resulting in significant savings for the client in both downtime and costs.