Cold curing beats welding for yacht windows

Louise Davis

It comes as no surprise that there are common problems associated with the harsh natures of conditions in the marine industry. For the most part, issues are caused by corrosion or erosion after years of operation. Usually, types of marine maintenance can fall into two categories. The first being at sea, typically with a small-scale repair or an emergency repair such as a leak. The other category being in dry dock. The characteristics of dry dock maintenance tend to be larger applications, in areas that can’t be accessed whilst out at sea, such as the propulsion system. On rare occasions however, we can also find problems occurring during the manufacturing stages. 

This was the case when the structure of a luxury yacht (designed by a top sports car manufacturer) had already been built, with a sudden change in the type of glass chosen for the windows. The window profiles were not compatible with the glass thickness. Lower thickness of glass required greater thickness of the metal window profile. A material would need to be able to be applied at a thickness of 1 – 1.5 cm (0.39 – 0.59 in) on to vertical frames.

This type of failure would clearly not be acceptable to such a prestigious design. It was therefore highly important that the problem could be solved with precision and taking as little time as possible in order to avoid any delay in the delivery.

The application needed to take place inside the 135ft/41.1m catamaran design. The $58 million craft features 472 square meters of interior space, accommodating 10 passengers and 10 crew members. There were 2 major affected zones in need of a solution. One of which was 148 linear metres long with a width of 5cm. The other being 68 metres long with a width of 10cm.

A solution was needed that would be capable of building up vertical surfaces to the required thickness without sagging. Traditional welding repair methods were considered but had a potential of damaging wood furnishings and interiors near the windows, as well as being expensive. Other work on the yacht was also taking place at the same time, meaning lack of space had to be considered. Therefore, the nature of welding would not have been suitable.

The customer turned to cold-applied metal rebuilding options. Materials from several manufacturers were considered and the decision was made based on slump resistance, as some vertical surfaces needed to be built up to 2.5cm.

Belzona 1121 (Super XL-Metal), a multi-purpose durable repair composite, was selected for the metal rebuilding. This would offer the use of moulds being a 100% solids epoxy material.  

The surface of the window profiles were initially prepared using a hand tool. As mentioned, precisely measured formers needed to be created for the alignment of the windows. Wooden formers were cut out, with Belzona 9411 (Release Agent) being applied for later removal once the material had cured. The material was worked into the surface of the former for a smooth finish. The material was then built up to achieve the correct thickness. The former with the material was then applied directly to the surface of the window profiles and pressed with clamps to ensure the best possible finish. Once cured, the formers were then removed and lightly abraded for an optimum finish.

The exact dimensions and geometry of the window profiles needed were able to be achieved, which was the fundamental part of the application, allowing the window glass to be fitted. The application was also able to be completed within the given deadline. 

This unique example illustrates a very common problem in a wide range of industries. Cold curing epoxy composites for metal rebuilding solutions are easy to apply, require no hot work and dramatically reduce downtime.


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