“When I was tasked with building and installing a new wheel at a historic water mill, I wanted to do it right. I’m proud of what we achieved, and the new wheel isn’t just beautiful – it will also last for decades,” says Tony Gray, Trust Joiner at the National Trust for Jersey.
Quétival Mill in St. Peter, Jersey, dates back to 1309, with the current mill building constructed in the 18th Century. After a major fire, the National Trust acquired the property and fully renovated it in the 1970s.
When the mill was originally restored, the Trust installed a new mill wheel but this needed replacing by 2003. Unfortunately, the replacement wheel, which was made of Pitch Pine, lasted just 12 years and needed replacing again in 2015.
As I’m the Trust Joiner for the National Trust for Jersey, the project to replace the wheel was my responsibility and I wanted to make sure that the new one would last for decades to come.
Choosing durable, environmentally friendly materials
After lots of research and consultation with experts, I decided to build the new wheel from Accoya timber, which is basically Monterrey Pine that’s treated with a process called Acetylation.
Monterey Pine is grown sustainably in California and other places and the only by-product from the treatment process is vinegar. That means the material was a good fit with our environmentally friendly outlook. The other great thing about Accoya is that it’s extremely durable and resistant to water and insect attack, so it really was the perfect choice for the new wheel.
Strength and durability with WEST SYSTEM epoxy
To glue the different elements of the mill wheel together, I chose WEST SYSTEM® epoxy products. These create bonds that are extremely strong, durable and water resistant. All that makes it ideal for a mill wheel that sits on the damp north side of an old mill building and frequently has water flowing over it.
WEST SYSTEM epoxy was critical to the success of the project because of the large number of wooden components that needed gluing together. Each rim of the wheel, for example, is made up of three laminates of 12 wooden pieces – that’s 36 pieces each side and 72 in total for the two rims. There are also buckets on the wheel, each with multiple wooden components, as well as eight spokes radiating out from the original iron drive shaft.
Mitigating build risks
We were very aware that such a large, complex wheel posed certain construction risks. It was possible, for example, that the glued bonds would not be strong enough to support such a large, heavy structure. In the end, we were able to mitigate this risk by working with experts from West System International, who provided advice and guidance for the project.
Specifically, they helped us to devise tests using the glue on samples in advance of the project and this process showed us that WEST SYSTEM bonds are extremely strong – perhaps even stronger than the wood itself.
We knew that gluing Accoya timber is tricky because of the acidity of the wood. West System International really helped with this by advising us on which products we should use and how we should mix them. The final solution was WEST SYSTEM 105 Epoxy Resin® with WEST SYSTEM 206 Slow Hardener®, plus a very light colloidal silica powder that brings the mix to a kind of tomato ketchup consistency and gives the bonds a huge amount of additional strength.
We used a two-stage process for the gluing which involved wetting the edges of the timber first with mixed epoxy . We then applied a mix that included the WEST SYSTEM® 406 Colloidal Silica to produce a thickened epoxy mix and put a layer of that on one side. It was then just a question of squeezing the timbers together firmly enough to bring them into position but without squeezing out the epoxy mix!
Water resistance for decades of use
Because of the inherent water-resistance of Accoya timber and the WEST SYSTEM epoxy bonds we didn’t need to epoxy coat the wheel, which would have added a lot of unnecessary weight and cost. Instead, we simply painted the wheel with four coats of water-resistant stain. With this as the only coating, the wheel will last for decades, even in the dampest conditions and with frequent use.
Protecting Jersey’s heritage with WEST SYSTEM epoxy
It’s been a great experience working with WEST SYSTEM epoxy products on the mill wheel and we’re very proud of the results we’ve achieved. It’s just one example of how the National Trust for Jersey is using extremely innovative technologies and approaches to restore very old buildings and sites to protect the island’s heritage.
The project has also shown me lots more possibilities for working with epoxy at the Trust. There was some product left over and I used it to restore a piece of Victorian furniture, for example. I’m now also using WEST SYSTEM products to laminate some doors for some Trust-owned Victorian houses on the island to make them as strong and as stable as possible.
West System International has also shared some literature with us on using WEST SYSTEM epoxy to restore listed buildings, so we’re also looking into that as another possible application in the future. Maybe one of our future projects with WEST SYSTEM epoxy will make it into Epoxycraft – watch this space!
To see the new wood and epoxy mill wheel in action, watch the YouTube video.
For more information or to contact the National Trust for Jersey, visit http://nationaltrust.je/