Page 209 - HS Full Catalogue 2015-2018
P. 209

THE MANUFACTURING PROCESS




            Each Haddonstone design is made to order. If the order is for a
            standard design, production can commence as soon as a colour has
            been agreed. If a custom design is required then a mould needs to be
            made. If the design is relatively simple, a window cill or coping stone for
            example, then the mould will be made of wood in the company’s wood
            shop. One of the skilled carpenters will interpret drawings to produce
            a precise mould, which is the exact reverse of the shape ultimately
            required. Timber moulds have a comparatively limited life compared
            to their fibreglass equivalents.  However, the speed with which timber
            moulds can be produced, combined with their relatively low cost,
            normally makes this type of mould more economical for the client.

            The production of a fibreglass, rubber-lined mould in the company’s
            studio is much more time-consuming and is only undertaken if the
            design is complex or if there are likely to be numerous castings over
            time. The work is one of the most highly skilled within Haddonstone,
            benefiting greatly from artistic and practical skills. Before such a mould
            can be made, it is first necessary to have a model. This can come from
            a variety of sources: it could be created by the neighbouring wood
            shop; it could have been carved from scratch by an in-house craftsman,   The How It’s Made TV crew filming stone being packed into a mould at
            normally in plaster, either replicating an antique piece for a restoration   Haddonstone’s Northamptonshire manufactory.
            project or afresh for a new design; it could be a pristine antique stone;
            or it could be a damaged original requiring restoration.     the stone is left in the mould until the next working day. The process
                                                                        of delaminating or stripping is probably the most visually rewarding of
            Once the master model has been created, the mould-making can   the entire production process, particularly for a fibreglass mould. The
            begin. This is done by rolling clay to a set thickness and covering the   fibreglass case is first stripped away, leaving the rubber around the
            entire model.  Over this a fibreglass case is formed. As this case will be   stone. The rubber is then carefully peeled away to reveal the stone
            completely inflexible, it has to be designed in such a way as to allow   design in all its glory. No finishing is required as the quality of mould
            its later removal. For this reason, some fibreglass cases can comprise   manufacture ensures that the design is perfect, although seam marks
            more than ten sections. Then the fibreglass case is removed, the model   are sometimes unavoidable.  It is at this stage that the first of many
            extricated and all traces of clay removed. The case is then reassembled   quality control checks is undertaken and the product is given a bar code
            around the model, there now being a void where the clay had previously   label, which will remain with it until delivery to the customer. The stone is
            been. Into that void is poured a specially developed rubber which   now strong enough to be transported outside the production area.
            has enough fluidity to fill every cavity whilst avoiding any air bubbles
            which would be seen in the finished design. After the rubber has set,   Like other companies in the industry, Haddonstone originally relied
            the fibreglass case is, once again, removed and the model extricated   on the vagaries of the English climate to ensure that the stone cured
            for storage. When the fibreglass and rubber case is reassembled, the   correctly. However, the effects of temperature, precipitation and
            void now left in the centre is the precise shape and size of the finished   wind made this a very inexact science. For this reason, the company
            design. Particular care is taken to ensure that any seam is in a position   introduced a vapour curing system in 1999 that gives the stone the
            where it is least noticeable. Whether wooden or fibreglass, without a   equivalent of fourteen days strength overnight. Not only does this give
            first-class mould it is impossible to create a first-class product.  the company a guaranteed curing system, it also reduces delivery lead
                                                                        times and storage problems.
            For semi-dry cast Haddonstone, the principal materials are limestone,
            white cement, sand and a small quantity of water. This produces a   Although some customers opt to collect their orders, most rely on
            Portland colour with other colours requiring the addition of pigment into   Haddonstone’s own transport fleet, the majority of which include
            the mix. Other key ingredients include plasticisers to improve workability   a demountable forklift to aid off-loading on site. Export orders are
            and aid compaction as well as waterproofers for durability. To ensure   dispatched by container or in specially constructed wooden crates.
            complete control of the production process, every single batch of raw   A similar operation to Haddonstone’s manufactory in Northamptonshire
            material delivered to the Haddonstone manufactory is quality checked,   exists at the company’s US manufactory in Colorado. In the UK and
            before it is used. The constituents of the mix are stored in high-tonnage   USA, Haddonstone also manufactures products by a wet-cast process,
            silos adjacent to the production area, before being mixed in small   called TecStone. Here, the mix is poured into the mould. This process
            quantities via computer controlled batching equipment and taken to a   gives a finish, once acid etched, much more akin to Coade stone and is
            workstation. At this stage, the mix has the feel of damp sand or earth.  ideal for larger products, complex statuary and contemporary designs
                                                                        where clients prefer a surface finish which does not weather quickly.
            The stone is gradually packed into the mould using a number of   Most recently, Haddonstone has developed an artificial stone reinforced
            ingeniously crafted tools. Whilst this is normally done by hand, some   with glass fibres, called TecLite. Products made by this process have
            moulds can be packed using pneumatic hand rammers. Once packed,   thinner walls and are consequently lighter.


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