Marine: Epoxy infusion on a grand scale: “We decided to go with a fully epoxy boat.”
Production Director Dave Skene of Solution Motor Cruisers is currently building a 60ft powerboat, known as the Solution60, conceived by Ray Davis and world-leading yacht designer Bill Dixon. Modern composite production techniques – including constructing the hull using epoxy infusion methods – have shaped his whole approach to this substantial project.
“I consider myself a modern boatbuilder,” says Dave Skene, who has spent nearly 40 years in marine construction since training as a carpenter and joiner. “I want to use the highest level of technology possible to make sure the product is as good as it can be.”
For much of his career, Dave’s commitment to innovation has led him to use WEST SYSTEM® epoxy and PRO-SET® epoxy products. His own company, Skene Yacht Services, specialised in building custom yachts, wooden hulls and hand-laid, swept-plank teak decks. Epoxy is central to all of these, whether it’s used in conjunction with glass cloth to provide an abrasion resistant sheathing on a wood epoxy hull or to provide strong, long-lasting adhesion between teak planks and substrates like fibreglass.
However, when Dave was asked to be part of an ambitious new plan to create a limited run of 60ft powerboats based on a design by Bill Dixon he was introduced to the latest production technique that he hadn’t used before – resin infusion with epoxy. As Solution60 has developed, it’s become one of the UK’s largest epoxy infusion projects.
Resin infusion: the basics
Resin infusion isn’t a new process – it was being used in aviation manufacturing in the 1970s but was also used in trials to produce polyester glassfibre boats principally to reduce the styrene emissions when hand laminating with polyester resin.
Resin infusion with epoxy involves dry laminating composite materials in a mould and then sealing the mould with an impermeable bag. A vacuum is then created, drawing the epoxy into and through the laminate using a distribution network of transport mesh, channelled core, pipes and manifolds. The pressure differential that the vacuum creates allows atmospheric air pressure to literally push the epoxy under the vacuum bag and infuse the dry composite stack with minimal air voids. This can produce exquisite quality epoxy composite laminates.
This sets it apart from the traditional hand laminating technique used during vacuum bag boat construction – where composite materials have epoxy applied by hand and a vacuum bag and numerous consumable materials applied so that when a vacuum is created air is drawn out of the structure during the curing process and equal pressure is applied over the laminate to ensure thorough consolidation of the composite materials.
The traditional process is a race against time –the working time of the epoxy is critical to enable sufficient wet out of the fabric and to allow the consolidation pressure from the vacuum bag to be effective. Air bubbles – which create structural weakness – are often left behind.
The full thickness of the laminate may be impossible to complete within the working time of the resin system. Structural core materials and additional areas of laminate may need to be applied in another laminating process.
Less mess, less waste
Resin infusion transforms this process. There is no need for hand-application of the epoxy, because materials are laid out and compressed when they’re dry. You can work on larger areas, by creating a large vacuum area and adding additional tubes. The epoxy content can be finely controlled – which means there is less waste and less weight. As you can reposition materials at any point before the resin is added, time pressures are no longer an issue. Very importantly the full laminate stack including core materials can be constructed in one process.
For Dave and his team, the process has been a revelation. “Now instead of becoming a messy laminating workshop, you can become a clean workshop,” he says. “I laminated a deck the other day wearing trousers, a shirt and a tie. You don’t even need gloves! You only require gloves when mixing the epoxy resin and hardener.
“We’re using a range of PRO-SET products – including PRO-SET INF 114 epoxy resin and 210/213 hardeners for infusion. It’s better for people’s welfare. It’s better for the environment. There is no waste. It saves time labour-wise. It creates a lighter boat, because you use the exact amount of resin you need and no more. And you get exactly the result you want.”
Having not used epoxy infusion before working on the Solution60 project, Dave sought advice from various experts, including David Johnson from West System International. He also studied the use of epoxy infusion in projects across Europe – from aircraft wings to windmill blades – and looked at how to optimise resin flow during infusion.
This research led to a number of innovations. A highly configurable heating system was introduced to the hull molds, featuring 84 programmable fields to support accurate infusion flows and post-curing. Tests were completed using PRO-SET epoxies to optimise the pot life, working time and gel times of the epoxy to suit the exact infusion flow time. The decision was taken to extend the use of epoxy to all Solution60 moulds – and beyond.
“We decided after listening to all of the expert advice to go with epoxy molds, as well as an epoxy-infused hull,” Dave says. “All of our molds use epoxy. And as time progressed, we’ve decided to go with what I call a fully epoxy boat – including decking and interiors.”
The decision to create moulds using epoxy was partly inspired by Dave’s previous experience combining various WEST SYSTEM epoxies.
“Everything is compatible, everything goes together,” he says. “You could choose to build an epoxy hull, a vinylester deck and polyester interior, and then glue them all together.
“But by using epoxy for everything – for infusion, laying up, or whatever else you use it for – it’s all the same material. The WEST SYSTEM epoxies are designed to work together, so it creates a stronger bond, and reduces the chance for human error because everyone is using the same products for every process.”
The current plan is for the first Solution60 boat to take to the water in the spring of 2015. “We plan to try and produce three or four boats a year,” Dave says. “They’re very luxurious and fully equipped. We don’t expect people to have to ask for extras.”
“What’s interesting about these boats,” he adds, “is that they have a slightly different design in the hull and they’re slightly wider than some powerboats, which creates more stability. So they’re very safe, but still cruise at speeds of 22 knots and can reach 29 knots. They don’t hang around.”
One of the first boats will be available for charter – and while many early passengers may be unaware of the role epoxy has played in their voyage, Dave considers it central to his team’s work.
“Epoxy is one of the best products you can get for marine construction,” he says. “It saves weight. It prevents water ingress. It has a huge range of uses.
“I think some boatbuilders can be a bit short-sighted and they use other materials to save costs,” he says, “rather than using the best available products on their boats.”
“But using epoxy means our boats will last longer than theirs and it’ll have a lot less problems. We don’t want any warranty issues. These are luxury boats, built to last – and epoxy is a big part of that.”