Case Study: E.H. Hassell & Sons
Case Study: E.H. Hassell & Sons

Case Study: E.H. Hassell & Sons

Traditional Marine Specification Productivity limitations and QC issues

Kortec have been supplying protective coatings to E.H. Hassell & Sons Ltd since 2007. We upgraded their system a number of times through to 2011 as their client increased their coating service life expectations — finally requesting “in excess of 15 years in a marine environment” (ISO12944 C5M-High). This was achieved using a traditional marine specification at the client’s request, involving a two-pack epoxy zinc rich primer, plus a two-pack epoxy zinc phosphate midcoat, followed by a two-pack polyurethane topcoat. This system had a total Dry Film Thickness (DFT) of 330 microns.


Due to the size/weight of the fabrications they produce, and the lack of any forced drying facilities, only one coating could applied per day to ensure it was sufficiently dry before lifting it back into the spray area for the next coat to be applied. This meant that the overall coating process took three days, and the topcoat took another two days to dry, before it was hard enough to assemble the various sections on the sixth day. 

EHH were also experiencing an unwanted level of Quality Control (QC) rejections from their client, which significantly impacted on the efficiency of their production schedules. Due to the complexity of the structures they produce, it was not easy to apply the coatings to the full DFT specified, and therefore additional coats had to be manually applied after assembly in critical areas. 

In other areas, large sections were bolted together under high torque, and where the high film thickness of the system combined with the extensive and brittle epoxy coatings, the paint was cracking around the bolt heads. This again required manual remedial work, making it difficult to reproduce the full system and thereby compromising the level of protection in areas with a high corrosion potential. 

EHH were managing to work within these constraints until their client advised them that they would need to be able to double the production output in order to fulfil potential orders on time. This was clearly not going to be practical with their current coating system and so they asked Kortec to assist them in carrying out a full review of their coating specification and process. 

Analysis - Open discussion with fabricator and client 

It quickly became apparent that it was essential to include both EHH and their client in the coating system review to ensure that any proposal met the requirements of both companies. We obtained defined specification from the client regarding their expectations of long term durability and QC standards, as well as gaining a clear understanding of the production process times that EHH needed to work to. 

Having discussed these requirements with our suppliers, we gave a joint presentation to both companies, supported by product test reports and physical test panels showing the results of salt spray and UV exposure tests. We were then able to respond to any queries, and established full agreement to the proposed system. 

Implementation - Product trials and system assessment 

The coating system selected uses products manufactured by Libert Paints (Belgium) for whom Kortec is the UK Distributor. It is a hybrid system based on a single-pack moisture cured polyurethane zinc rich primer, followed by two coats of a two-pack polyurethane primer/finish coating applied “wet-on-wet”. This met the criteria set in the following ways: 

DAY 1: Single-pack moisture cured polyurethane zinc rich primer applied. 

DAY 2: Two coats of a two-pack polyurethane primer/finish coating applied. 

No need to move items out of the booth between coats; minimising handling time. 

DAY 3: Through dry and ready for assembly. 

RESULT: Potential to double productivity achieved. 

Overall DFT required is only 190 microns (40% reduction) and all coatings are flexible polyurethane resins. 

RESULT: DFT specification consistently achievable. Coating compression issue reduced from approx. 80% failure to 5-10%. 

Test results showed 1440 hours resistance to salt spray and minimal colour/gloss change after 1500 UV testing. 

RESULT: Client specification for ISO 12944 C5 Marine – High (15+ Years) achieved. 

Training And Monitoring

Product application training was provided to ensure the applicators were confident in obtaining the optimum performance from the coatings. 

Wet and dry film thickness testing was undertaken to help applicators achieve the specified levels. 

Liaison with the Production Manager enabled us to monitor the increase in productivity. 

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