Producer of enamelled steel products for architectural applications Vitrex has supplied ten Vitraflex toilet cubicles for mobile operator Vodacom’s Techno Centre, in Bellville,
The cubicles are constructed using a combination of vitreous enamelled steel and rigidised stainless steel.
Cape Town-based Vitrex distributor Facade Projects managing member Amanda Ellis says the contract follows an original Vitraflex installation of 50 cubicles at the Vodacom Techno Centre 12 years ago.
“The client was happy with the performance and appearance of the Vitraflex cubicles and wanted to retain the system for the exten- sion of the centre. The Vitraflex system has proven itself in terms of efficiency, minimal maintenance and hygiene,” she explains.
The combination of vitreous enamelled steel and rigidised stainless steel was used for the Vitraflex partitions, while the cubicle doors featured stainless steel externally and vitreous enamel internally.
Vitrex sales and marketing director Cristian Cottino says the new installation is a striking example of how two surfaces can be combined to form one cubicle.
“Vitreous enamelled steel is a standard component of Vitraflex toilet partitions but Vitrex can, on request, offer alternative finishes, such as formica, melamine, and rigid- ised stainless steel for cubicles,” he adds.
To produce the vitreous enamelled products, raw materials – borax, silica, cobalt, nickel, titanium and others – are smelted together in a kiln at about 1 200 ºC for four hours and, immediately on removal from the kiln, rapidly cooled using cold water. The shock shatters the molten mixture into fine particles called frit.
Along with water, the frit and other materials, including clay and colouring pigments, are milled in ceramic-lined ball mills to a cream-like consistency called slip. The slip is then ready for direct application, using a wet spray process, onto the metal surface that has been prepared for enamelling.
Modular Cloakroom Cubicle Systems
A computer-aided design (Cad) system is used to create working drawings to the client’s specifications.
A computer numerically controlled laser cutter is programmed, using digital information from the Cad system, to cut the sheet steel to shape and create the required fixing holes.
A variety of techniques involving spinning, press brakes, guillotines and welding is used, according to requirements, to form the complex rectangular and curved shapes. Corners are welded and finished to complete the sheet steel profile.
Every panel goes through a chemical process to remove contamination and provide an etched surface to receive the enamel. The special low-carbon steel is chemically pretreated, which involves alkaline degreasing, acid pickling and surface passivation to ensure 100% adherence for the glass coating.
A first coat, or ground coat, of vitreous enamel is applied to all surfaces and dried at between 200 ºC and 300 ºC, leaving the enamel in a bisque form on the steel.
Panels are preheated to 400 ºC before entering the furnace.
The chemical fusing of the vitreous enamel to the steel base takes place at about 820 ºC. Upon firing in the furnace, under closely controlled conditions, the ground coat is chemically bonded to the steel base. The powder melts, flows and hardens to a smooth, durable vitreous coating on the metal.
Subsequent colour coats are applied, depending on the specification.
The second coat, or cover coat, is specially formulated with, for example, titanium-based frits, suspending agents and ceramic pigments to provide chemical resistance, abrasion and wear resistance, colour and texture. It is applied in the same way as the ground coat and is once again fired at 820 ºC. After two cover coat layers, the overall thickness of the coating is increased to between 250 μm and 350 μm.
Various substrates are then bonded to the panel after being passed through an adhesive curtain coater. These can provide additional structural strength, and thermal and fire-resistant properties. There are a number of core materials available for laminating with adhesives to the inside face of the panels, either as a single layer or as part of a composite construction.
The selection depends on the type of panel being specified and the performance required. The range includes asbestos-free fibre insulating boards, calcium silicate fire-resistant boards, mineral fibre rigid foamed polyurethane and phenolic resin boards bonded with a neoprene-based adhesive.
A recent addition has been the introduction of aluminium honeycomb constructions, bonded with an epoxy resin adhesive in various sizes to suit the loading requirements. This core, in particular, has permitted the design of large, exceptionally flat panels requiring a minimum number of fixings.
Vitraflex cubicles and vanity tops are imper- vious to chemicals, spray paints, and bac- terial or mould growth. Colours are permanent and the partitions are graffitiproof and easy to maintain. A standard range of 20 colours is available with an almost unlimited choice on special request.