How we combine modern technology with traditional production methods

All Haddonstone cast stonework products are made to order and are hand crafted at our own Northamptonshire manufactory. This ensures we maintain full control from start to finish, so only the highest quality products reach our clients.

Our production methods involve various processes, from mould making and packing, to de-moulding, and vapour curing. It can also include adding structural reinforcement and taking advantage of new technology innovations such as 3D modelling. These new ways of working have enabled us to meet changing client demands and improve production efficiencies.

But how do we bridge the traditional craftsmanship, that is so important to our production, with the benefits of new technology?

What is the ‘traditional’ way of working with cast stone materials?

Haddonstone manufactures three high-specification cast stone material options to suit a broad range of unique requirements. These are:

• Haddonstone (semi-dry cast limestone)
• TecStone (wet-cast limestone)
• TecLite (fibre-reinforced).

Find out more about each of these materials:

Adhering to standards

As part of our Quality Assurance procedures, we regularly test all of our materials to ensure they meet the high levels of quality and durability required. We send samples of our three materials to accredited test laboratories, depending on the material involved, up to four times per year. This includes the Capillary Absorption Test, which tests for the permeability of the stone by reviewing how long the pressure of water takes to penetrate the surface.

As a founding member of the United Kingdom Cast Stone Association, it is imperative that all of our materials meet or exceed the strict levels of technical performance as set out by this trade association.

Weekly test cube inspections are also carried out, whereby test cubes are tested to destruction, to ensure consistency of strength. The building specification requirement as governed by the United Kingdom Cast Stone Association is 35 newtons and we consistently manufacture well in excess of this.

Finally, we also test how our materials look aesthetically so that our high standards are always maintained. We do so by a visual inspection involving several people and during all stages of production, from creating the material, to stripping the mould and finally checking the surface texture for any imperfections such as air holes, cracks or inconsistencies.

Our process

Our stonework is all hand crafted and made-to-order.  Our in-house craftsmen use finely tuned artistry, teamed with years of experience in order to produce the highest quality cast stonework on the worldwide market.

If we receive an order for a standard design, then production can start as soon as a colour has been decided.  But if the order is for a bespoke design, a unique mould must first be made.

For our TecStone and TecLite materials, the production method may also involve adding structural reinforcement, and or mechanical fixings.

Curing is an essential process applied to de-moulded cast stone as it helps both its appearance and long-term strength and durability. The curing process can take over two weeks to achieve a satisfactory strength, depending on the size of the cast stone component.

To speed up this process, we have invested in an accelerated vapour curing chamber at our manufactory. Vapour curing gives the stone the equivalent of 14 days’ strength overnight, which results in reduced delivery lead times and improved handling.

Find out more about our mould production and processes:

Merging traditional skills with technology

Our production methods are still very traditional, however we have begun to introduce technology to both assist with our manufacturing, as well as to ensure we are able to meet our clients’ high standards.

For simple designs, 3D scanning works well, however for more decorative and detailed projects, traditional skills are essential – you simply can’t replace these talents.

We are increasingly turning to 3D modelling to assist with our restoration and replication work. For example, this technology was crucial for completing a recent project in situ at Kinnaird Castle in Angus, Scotland.

The owners of Kinnaird Castle first approached Haddonstone in 2016 to discuss their balustrade restoration project. After years of weathering and frost damage, the original stone balustrade that runs along the entire circumference of the castle had deteriorated and crumbled.

To ensure our team could reproduce the original balustrade to our client’s exact specification, we produced one sample baluster, which our client left outside to age naturally for four years. For the majority of our restoration and replication projects, our studio team travel to our clients’ sites to take the necessary mouldings of the original stonework. With last year’s Covid-19 travel restrictions, this proved problematic.

However, we were keen to ensure that we could meet our client’s brief and precisely replicate the original balustrade. We therefore commissioned a local leading 3D printing company to provide both a 2D profile as well as an interactive 3D model of the existing balustrade and rail designs.

This allowed our team to quickly and accurately produce new timber models using our in-house lathe, from which they then produced fibreglass and rubber moulds to cast the replacement balustrade and railing.

Read the case study:

Manufacturing techniques

In recent times, we have developed a tool handler which has solved an industry wide problem with pneumatic tools.  With our Haddonstone dry-cast material, we use a pneumatic rammer which essentially drives the material into the mould.  This causes a lot of vibration, which is a health and safety issue.  New technology has enabled us to add a timer to the tool, so that any one team member can only use it for 1.5 hours a day.

We have also introduced a robotic arm for operators to hold, which again, improves the comfort for the user and means that they guide it and do not have to pick up and put down every time.

These introductions do not solve all of our production issues, but 70% of dry cast products made using these new techniques and productivity has increased as our colleagues do not become so tired.

We still utilise the more traditional carving methods in our in-house studio. However, the big change has been with our model making, which has been replaced from originally using wood, to model board, which is a manmade composite material.  This is a stable material that is much easier to work with as it is softer to lathe.

Wood created some technical issues. For example, due to the natural grain variations, once the model was made in timber, it would have to be glued together.  Wood can split or crack, especially when making the glass and rubber mould off the model.  The heat used in model making can also damage the wood by warping and twisting it.

What does the future hold?

Moving forward, we will be completing the extension of our TecStone facilities in the summer of 2021. This is in response to greater numbers of client orders requiring this material option and it is great to be investing in our facilities during the current economic climate.

We will also continue to shred and recycle our wooden moulds.  We make around 200 bespoke and standard moulds each month and many are unable to be reused for other projects, so they end up being scrapped and going to landfill.  A shredder at the factory crunches the wood, producing around 50 tonnes of wood per year.  This goes towards heating the factory, thereby saving energy and helping environmentally.

Ready to help with your next project

Our experienced and friendly team has been helping clients complete their projects, with and without structural reinforcement, for the past 50 years.

Whether you have a new project in mind, or would like to chat through some ideas, our team are on hand to assist you.

Arrange your free project consultation today.

Call:    01604 770 711

Email: [email protected]