GB2539127A

GB2539127A - Cast iron-effect products and fittings

Info

Publication number: GB2539127A
Application number: GB1615474.2A
Authority: GB
Inventors: Millward Keith
Original assignee: Polypipe Ltd
Current assignee: Polypipe Ltd
Priority date: 2010-08-27
Filing date: 2010-08-27
Publication date: 2016-12-07
Anticipated expiration: 2030-08-27
Also published as: GB2539127B; GB2483112A; GB201615474D0; GB201014381D0; GB2483112B

Abstract

A plastic rainwater or soil fitting 100 including a cast iron effect finish 13 on an outer surface thereof, and at least one jointing surface 2 formed with a smooth surface. The smooth surface does not feature a cast iron effect finish, and is intended to contrast with the portion having the cast iron finish. The smooth surface may be relatively reflective, in comparison to the cast iron effect surface. The plastic fitting may be joined to one or more other rainwater or soil fittings at the jointing surface, the smooth surface being masked by the other fitting.

Description

Cast iron-effect products and fittings The present invention relates to cast iron-effect products or fittings and methods for manufacturing such cast iron-effect products or fittings. Usually the products or fittings will be made from a plastics material. The method is, broadly speaking, a moulding technique.

There is a growing requirement to make plastic products, and in particular gutter fittings, down-pipe fittings and soil pipe fittings which have the appearance of traditional cast iron products. Such cast iron effect products can be highly desirable, or essential, where listed building consent might be concerned, especially in building projects such as the renovation of old buildings. In such projects, it can be important to maintain the external appearance of the old cast iron products that are being replaced or matched by the new plastic products.

Manufacturers of plastic rainwater/soil waste systems have thus been working towards the production of cast iron effect products so as to retain the benefits of the conventional plastics manufactured systems, such as the cost benefits compared to the cast iron equivalents, and the uniformity-of-shape capabilities, the lightweight nature thereof, their corrosion resistance and their reliability-in-use characteristics. However, to date, the cast iron effect products produced have not been entirely satisfactory.

For example, known plastic rainwater fittings of the above kind have typically been manufactured either by rotational casting the products within moulds which have contact surfaces that have been intentionally roughened -see GB2355474, or by painting conventional smooth plastic extrusions or mouldings with special paint systems which give the finished/painted products a textured outer surface. Indeed, a number of methods for making such prior art cast-iron effect rainwater products using rotational casting is disclosed in GB2355474. Those methods include sand-casting the mould such that it has a textured finish, or galvanising or plating at least the interior of the mould in a crude manner. These approaches, however, all ultimately only provide an appearance that approximates the finish of an old cast iron product. However, the appearance is often too flat to be entirely convincing -the finished products, when installed alongside original cast iron products, will not fully blend in -they look too new.

These methods therefore can only resemble the features of a new cast iron product; the external texture of the fittings made by these methods will not give a true representation of a cast iron product that has been in situ for a number of years. After all, the texture of an old cast iron item will combine features and imperfections of the original sand casting, together with both any additional corrosion marks that would have occurred thereafter, and imperfections arising from areas where paint has flaked off. Further, the moulded finish can compromise the structural and hydraulic security of the fittings, and their ease of jointing of one product relative to another, when it comes to installing these moulded components of the rainwater system.

It is also to be observed that within the plastics processing sector, rotational casting is a relatively low-volume process that can result in high unit cost. Further, it also generally cannot give close-tolerance jointing dimensions anyway, especially on the internal surfaces, which can further compromise the structural and hydraulic security and, at the same time, ease of jointing, when it comes to joining the rotationally moulded components of the rainwater system together.

As for the painted options, the cost of painting is a significant proportion of the total cost of the products, whereby the products are not able to be competitively priced compared to the standard, non-textured, plastics products.

The present invention, therefore, seeks to overcome or mitigate at least some of the above disadvantages and/or constraints, and/or to provide improved cast iron-effect plastic rainwater or soil articles, products and fittings -hereinafter referred to as fittings.

According to a first aspect of the invention, there is provided a method of moulding plastic rainwater or soil fittings, the fittings comprising a cast iron-effect finish on an outer portion thereof, where the method comprises: producing a female mould cavity for the products or fittings, the mould cavity being produced by a method comprising measuring a topography of at least a portion of an outer surface of a cast iron product, generating a computerised representation of that topography, transferring that computerised representation onto a mask and using that mask to selectively work a surface of a representative mould cavity, whereupon that represented topography is recreated onto that representative mould cavity; and using the female mould cavity to manufacture the plastic fittings.

The female mould cavity will typically be one of numerous elements forming the mould. That mould, for example, can comprise additional female mould cavities and one or more core elements, e.g. to form the inside of the plastic fitting.

It is possible for only one or some of those elements to utilise this cast iron effect producing method. For example, the cores typically will not utilise this method since the non visible parts of the fitting need not have cast iron effects added to them.

Preferably the cast iron product from which the topography is measured is a used, cast iron, rainwater fitting or a used, cast iron, soil fitting.

Preferably the cast iron product is of the same type as, and of the same general shape and size as, the plastic fittings moulded by the method.

Preferably the cast-iron product is an old product, i.e. one that has been in external use for at least several years, and perhaps painted more than just once. The product thus has a distinctive, textured, irregular, surface, including marks from the layers of pain, marks from rust and marks from other degrees of corrosion or wear/use. It could, however, instead be a new or unused cast iron product.

Preferably the measured topography is measured by a non-contacting technology.

Preferably the non-contacting technology comprises three-dimensional laser scanning.

Preferably the recreated topography extends over the majority of the worked surface of the representative mould cavity. It can also be over the entire worked surface, such as for fittings in the form of gutter fittings, or other fittings where the entire outer surface will be visible in the finished use of the product.

Preferably the working of the surface of the representative mould cavity comprises masking at least a portion of the surface of the representative mould cavity with the mask, the mask taking the form of a masking film.

Preferably the working of the surface of the representative mould cavity is an etching process.

The etching process can comprise a single etching cycle, i.e. just one etching cycle, or at least two separate etching cycles, such as just two or just three separate etching cycles, etc. Additional or multiple etching cycles can produce a better representation of depressions in the texture, especially those that have curved or angled surfaces.

Preferably the etching is carried out through a mask in the form of a protective flexible film applied to the representative mould cavity, and wherein the protective film has apertures or grooves defining the computerised representation of the measured topography to allow an etching agent to act through the film on areas of the representative mould cavity in accordance with the computerised representation of the measured topography.

Where at least two working cycles are applied to the surface of the representative mould cavity, preferably a separate mask is applied for each cycle, each mask having a different computerised representation of the measured topography, the computerised representations representing different layers through the measured topography, whereupon depths of working of the surface of representative mould cavity can be selectively controlled in consecutive working cycles.

Consecutive working cycles can be used to produce or form stepped profiles for certain areas of the representative mould cavity, those stepped profiles approximating curved profiles measured from the cast iron product.

Preferably the mask is in the form of a flexible film, that film being a photosensitive film.

The representative mould cavity can be a negative mould, featuring an inverse representation of the measured topography, the recreated topography being applied to an inner surface of the representative mould cavity.

Preferably the representative mould cavity is the female mould cavity.

The representative mould cavity might also be a positive mould cavity, featuring a direct representation of the measured topography, the recreated topography being applied to an outer surface of the representative mould cavity. The female mould cavity is then produced as a casting/moulding from the representative mould cavity.

Preferably areas of the representative mould cavity are masked off from the working step or steps with separate masking elements such that those areas are not worked during the working step or steps.

Preferably the separate masking elements are applied as a wax or as a tape.

Preferably the representative mould cavity is a master mould from which the female mould cavity can be produced.

Preferably the use of the female mould cavity to manufacture the plastic fittings is a use in an injection moulding process. However, the mould cavity could equally be used in other moulding techniques, such as compression moulding, blow moulding, and potentially also rotational moulding, i.e. to improve upon the realism of the products produced thereby. With rotational moulding, no core is needed, so that typically has a lower tooling cost (the cost of making the moulds), which can thus make it more suitable for lower volume product runs.

The present invention also provides a method of moulding plastic rainwater or soil fittings, the fittings comprising a cast iron effect finish on an outer surface thereof, where the method comprises: providing a female mould cavity having a textured inner portion representative of the cast iron effect finish, in negative form; and using the female mould cavity to manufacture the plastic fittings by injection moulding or compression moulding or blow moulding.

The fitting is preferably a fitting that does not feature a swan neck, and the moulding technique preferably uses a core for forming the inside of the fitting.

The female mould cavity can be formed with at least one smooth-surfaced portion for forming at least one external jointing surface of the plastic rainwater products with a correspondingly smooth surface, which smooth surface does not feature a cast iron effect finish, and which smooth surface will contrast with the cast iron effect finish elsewhere on the products. This is useful for jointing surfaces -surfaces that will be fitted into sockets or the like. The female mould cavity might, however, have the cast iron effect across its whole moulding surface.

Gutter fittings typically have the case iron effect across the whole external surface, whereas down-pipe fittings often have jointing surfaces which will become hidden in use. By minimising the extent of application of the present invention's method to the mould's component parts, the lower the cost of the provision of the mould. As such, where surfaces do not need a cast iron effect (because they will be hidden in use) it I preferred that those surfaces are not given the cast iron effect. As such, the corresponding parts of the mould cavity are not so processed.

The present invention also provides a plastic rainwater or soil fitting comprising: a cast iron effect finish on an outer surface thereof, and at least one jointing surface formed with a smooth surface, which smooth surface does not feature a cast iron effect finish, and which smooth surface contrasts with the portion with the cast iron effect finish.

The smooth surface can be relatively reflective, compared to the cast iron effect surface(s). This readily provides a contrast between a cast-iron effect surface and the smooth surface.

The smooth surface of the jointing surface facilitates a good seal between that jointing surface and a corresponding surface of another rainwater or soil fitting to which that jointing surface is to be connected. The smooth surface of the jointing surface -usually at one, both, or each end of a fitting, thus facilitates a leak free coupling thereof with another part, which leak free coupling would be difficult to achieve if instead using a textured surface (such as a cast iron finish).

Preferably the plastic rainwater or soil fittings are one of, or include, an elbow or bend, a shoe, a branch, a gutter angle, a length of down pipe, a union bracket, a hopper, a facia bracket, a running outlet, a stop end outlet, a stop end or a mounting bracket.

A length of gutter/soil pipe/downpipe might be attached to that fitting.

The product might also include a swan neck.

The present invention also provides for a use of a plastic rainwater or soil fitting as described above, wherein the fitting is joined to one or more other rainwater or soil fitting at the jointing surface, the jointing surface's smooth surface being fully masked by the one or more other rainwater or soil fitting.

The present invention therefore provides rainwater or soil fittings, and methods for the production of rainwater or soil fitting, the fittings having outer surfaces which are provided with a cast iron-effect texture applied during their manufacture. The fittings, typically mouldings, for example gutter, soil or down-pipe fittings, will be able to more closely resemble original cast iron products, such as the ones that they are either complementing or replacing on a building. That is because the pattern of the texture will be predefined to resemble the surface of an actual aged and painted cast iron product, rather than being effectively just a random form (as occurs with the sand-cast effects achieved in the prior art).

With the present invention, it is also to be observed that all painting costs can be eliminated, either in the manufacture of the products, or later -i.e. upon installation on the building, whereby issues of paint adhesion do not have to be considered.

Further, the corrosion and external weathering performance will be the same as with conventional, non "cast iron effect" PVCu systems, which are known, from long term usage, to have good performance characteristics in those respects. After all, the same materials are being used.

Additionally, with the present invention any jointing surfaces can be moulded to respect close tolerances, the same that can typically be achieved with conventional, non "cast iron effect" injection moulded rainwater products. That is because the cast iron effect achieved with the products of the present invention can be selectively applied to the products of the invention, whereby the decorative effects that might compromise the connectivity performance of the products, can be excluded from the jointing surfaces.

These and other features of the present invention will now be described in greater detail, purely by way of example, with reference to the accompanying drawings in which: Figure 1 is a schematic representation of a partial cross section though a wall of a cast iron rainwater component showing its typical surface texture irregularities on a part of its outer surface; Figure 2 is a two-dimensional computerised topography illustrating a representation of the irregular surface of that section of the cast iron rainwater component of Figure 1; Figure 3 is a schematic representation of a cross section of part of a mould cavity for moulding an article of rainwater furniture, reproducing the topography of Figure 2 on a surface of the article in accordance with the present invention; Figure 4 is a schematic representation of a partial cross section through a wall of a rainwater article, or fitting, having a cast iron-effect finish corresponding to the mould cavity of Figure 3, manufactured in accordance with the present invention; Figure 5 is a side by side comparison of the two schematic representations of Figures 1 and 3, showing the approximately matching male-female cross sections of a) the cast iron component of Figure 1 and b) the mould cavity of Figure 3, the latter being formed from a multiple-layer etching concept, for example involving 3 stepped etchings for approximating the original form of the surface of the cast iron product; Figure 6 shows a cast iron-effect rainwater fitting manufactured in accordance with the present invention; and Figure 7 shows a more detailed view of a sample cast iron-effect rainwater product manufactured in accordance with the present invention.

As shown in Figure 1, the starting point of the manufacture of a cast iron-effect rainwater product, or of a soil product, in accordance with the present invention is to take an actual cast-iron rainwater fitting 5, which, for ease of reference will be said to be a hopper head, and typically one which may have been in use for several years. From that actual cast-iron product, any loose scale is initially removed from the outer surface 6. Then the outer surface 6 is scanned, generally using a non-contact technique (e.g. three dimensional laser scanning), in order to obtain and provide a computerised representation -typically digital information, or digital data -of the detailed surface topography 3 of the outer surface 6 of the hopper 5.

After that acquisition of data, the data can be generalised mathematically so that it could be applied to any rainwater product, or any soil product, rather than just the product category of the scanned product, i.e. not just hopper heads.

Alternative techniques to gather the above cast-iron texture data may alternatively be used. For example there are numerous different techniques for capturing two-or three-dimensional surface data, such as depth profiling using a scanning needle, or photo-scanning, as it is known in the art.

The captured/generated data is then used to re-create or add, or just to transfer, the textured topography onto a mould cavity for a rainwater product -preferably a plastic hopper head of the same general shape as the original cast iron hopper head, although with the generalised data it could be applied to other shapes of product.

The original topography 3 of the cast iron product will have to be re-created on the mould cavity 7 in negative form (the topography of the actual rainwater hopper 5 is referred to as a "positive" or "male" topography). The corresponding topography 20 of the mould cavity 7 will thus be referred to as a "negative" or "female" topography. This is represented in Figure 3. This allows the moulded product, as produced from this negative, to have the required positive topography representative of the original cast iron product. However, it is also known in moulding processes to form a master mould from which process moulds are formed. This is thus also able to be used as an additional process step for forming the mould cavity against which the finished articles are moulded. With this approach, the master mould may be a positive mould, and the negative process moulds are then formed from that master mould. Nevertheless, a direct production of a negative mould is generally preferred here.

The method of transfer can be via any one or more of numerous known techniques in the moulding industry. Good results, however, can be achieved using etching, and photosensitive flexible films, e.g. of the kind that can be printed with an optical means in high detail, are an effective method of controlling the application of that etching. Using such films, either as a single film template or as multiple, staggered, film templates, accurately indexed relative to one another, can highly effectively incorporate the topography 4 of the original scanned surface 6 onto the mould cavity. This can be achieved in a stepwise manner, building the etched surface up one layer at a time using single or multiple etching steps. It will thus be understood that the printed and unprinted areas on the film will correspond to "etch" and "non etch" areas, or vice versa, as appropriate, such that non etch areas will form a mask against etching, by protecting the mould cavity's surface 12 against etching agents, such as acid, whereas the "etch" areas will allow etching to take place -the etching will remove a layer of material from the surface 12 of the mould cavity 7 in accordance with the template's design.

The topography can thus be applied easily to any curved or flat surface of the mould cavity, selectively (i.e. it can be applied just to selected areas of the mould cavity -see Figure 6).

Using multiple etching steps, a complex 3D topography can be recreated, with different levels/depths of etching in different locations.

Curved surfaces or recesses of an original cast iron product can even be created, for example as a representative set of etched steps; the greater the number of steps used, the closer to the original curve can the approximation become.

Further, deep and shallow recesses can also be created, by selectively etching areas of the mould cavity with more or fewer etching steps.

Repeat layering with the film templates, each potentially of a different design, can thus achieve many different etch profiles on the mould cavity. It is necessary, however, to accurately index subsequent templates in order to achieve a predefined final etch profile since subsequent layers of film must align with previous layers to ensure that the stepped topographical features to be formed are correctly formed as per the desired design. See Figure 5, and the three separate layers 30, 31 and 32, for an illustration of the layered formation of the surface profile.

The etching process can be carried out as follows: The mould cavity to be textured -typically a component part of an injection moulding tool, or a blank thereof -is first of all prepared by cleaning the moulding surfaces by, for example, solvent cleaning. That component will have already been formed to the basic shape of the negative of the product to be produced (or at least to the shape of the negative of a part of that product to be produced).

Then any designated areas on the cavity which are not to be etched, such as jointing surfaces, are protected by using acid resistant tape, wax, etc. to avoid an etching thereof in the following steps.

Next the appropriately prepared flexible film templates are fitted onto the inside of the mould cavity. Typically they will follow the surfaces 12 of the parts 23 of the mould cavity 7 which are to be etched in a close-fitting manner. However, if more than one flexible film is to be utilised (such as when several etching iterations are required to produce the desired formations within the surface of the mould cavity), then the films will want to be provided with mechanisms for allowing an accurate indexation of subsequent films, such as fixed indexing marks. This is to ensure that the actual topographical features to be reproduced are correctly reproduced.

Figure 5 illustrated a possible multi-step application of etching acid, as shown by the three etch levels 30, 31 and 32. The first etching 32 will remove material closest to the protected surface 50. The second and third etchings 31, 30 will remove subsequent layers of material, i.e. at an increasing depth measured from the un-etched surface 50.

The mould cavity's surface is thus etched with acid so as to etch the areas of the mould cavity where the metal of the mould cavity is exposed through the film or films in order to arrive at the desired textures surface for the mould cavity.

The type of acid for use in this process is selected dependent upon the type of metal to be used for the manufacture of the mould cavity, and further dependent upon the type and depth of the required surface pattern.

The method of application of the acid can also be dependent upon one or more of those factors. For example, the mould cavity could be completely immersed in the acid or the acid could be sprayed through the apertures in the film or films onto the exposed surfaces therethrough.

The time or duration of the exposure to the acid can also be controlled to give the required depth of etch per treatment.

After the etching has taken place, the acid is thoroughly cleaned from the mould cavity's surface and then the mould cavity is ready to be used in the injection moulding apparatus to build up that tool into a complete injection moulding tool. That tool can then enable the injection moulding of multiple plastic versions 100 of the desired product -the positive form from the built-up mould(s), with the desired replication of the cast-iron effect pattern 13 from the original cast iron product. An example of a finished cast iron-effect product produced by such a process is shown in Figure 6, and parts thereof are shown in Figure 4.

Other methods can alternatively be used to form the desired topography 20 on the surface 12 of the cavity (or at least on a limited portion 9 of that surface). For example, the mould 7 could be sculptured using a micro machine, or a laser, or it could be selectively plated or eroded with a spray mist.

With the mould cavity thus formed, i.e. with the textured negative surface, high volumes of the required rainwater or soil fittings can be moulded, with injection moulding techniques being preferred due to their high volume capabilities. The final plastic rainwater or soil articles 100, with a cast iron effect on a desired surfaces thereof, i.e. typically at least all of the visible surfaces thereof in their final condition of use (but preferably not on any jointing surfaces), can thus be produced cheaply and effectively.

Figure 6 shows a typical example of an offset bend 100 showing the cast-iron effect finish 13 taken from an actual cast iron product, such as a hopper head 5, and made using the method described above. Figure 7 then shows a close up of the textured finish.

As shown in Figure 6, a spigot or jointing surface 2 has not been given the textured finish. Hence that jointing surface could be joined to another component with a watertight seal (such as by using a rubberised seal). Although such joints are typically unnecessary in down-pipes, such joints can be preferred with soil fittings so as to contain odour. After all such joints in soil fittings often utilise a rubber sealing ring, or some other such sealing element. This additional capability is thus highly advantageous.

The present invention has thus been described above by way of example. Modifications in detail, however, may be made within the scope of the claims appended hereto.

Aspects of the invention may also be defined by means of the following numbered clauses: Clause 1. A method of moulding plastic rainwater or soil fittings, the fittings comprising a cast iron-effect finish on an outer portion thereof, where the method comprises: producing a female mould cavity for the products or fittings, the mould cavity being produced by a method comprising measuring a topography of at least a portion of an outer surface of a cast iron product, generating a computerised representation of that topography, transferring that computerised representation onto a mask and using that mask to selectively work a surface of a representative mould cavity, whereupon that represented topography is recreated onto that representative mould cavity; and using the female mould cavity to manufacture the plastic fittings.

Clause 2. A method according to clause 1, wherein the cast iron product from which the topography is measured is a used, cast iron, product.

Clause 3. A method according to clause 2, wherein the cast iron product is of the same type, and of the same general shape and size, as the plastic fitting moulded by the method.

Clause 4. A method according to any one of the preceding clauses, wherein the measured topography is measured by a non-contacting technology.

Clause 5. A method according to clause 4, wherein the non-contacting technology comprises three-dimensional laser scanning.

Clause 6. A method according to any one of the preceding clauses, wherein the recreated topography extends over the majority of the surface of the representative mould cavity.

Clause 7. A method according to any one of the preceding clauses, wherein the working of the surface of the representative mould cavity comprises masking at least a portion of the surface of the representative mould cavity with the mask, the mask taking the form of a masking film.

Clause 8. A method according to any one of the preceding clauses, wherein the working of the surface of the representative mould cavity is an etching process.

Clause 9. A method according to clause 8, wherein the etching process comprises at least two separate etching cycles.

Clause 10. A method according to clause 8 or clause 9, wherein the etching is carried out through a mask in the form of a protective flexible film applied to the representative mould cavity, and wherein the protective film has apertures or grooves defining the computerised representation of the measured topography to allow an etching agent to act through the film on areas of the representative mould cavity in accordance with the computerised representation of the measured topography.

Clause 11. A method according to any one of the preceding clauses, wherein at least two working cycles are applied to the surface of the representative mould cavity with a separate mask for each cycle, each mask having a different computerised representation of the measured topography, the computerised representations representing different layers through the measured topography, whereupon depths of working of the surface of representative mould can be selectively controlled in consecutive working cycles.

Clause 12. A method according to clause 11 wherein consecutive working cycles produce stepped profiles for certain areas of the representative mould cavity, those stepped profiles approximating curved profiles measured from the cast iron product.

Clause 13. A method according to any one of the preceding clauses, wherein the mask is in the form of a flexible film, that film being a photosensitive film.

Clause 14. A method according to any one of the preceding clauses wherein the representative mould cavity is a negative mould, featuring an inverse representation of the measured topography, the recreated topography being applied to an inner surface of the representative mould cavity.

Clause 15. A method according to clause 14, wherein the representative mould cavity is the female mould cavity.

Clause 16. A method according to any one of clauses 1 to 13, wherein the representative mould cavity is a positive mould cavity, featuring a direct representation of the measured topography, the recreated topography being applied to an outer surface of the representative mould cavity.

Clause 17. A method according to any one of the preceding clauses, wherein areas of the representative mould cavity are masked off from the working step or steps with separate masking elements such that those areas are not worked during the working step or steps.

Clause 18, A method according to clause 17, wherein the separate masking elements are applied as a wax or as a tape.

Clause 19. A method according to any one of the preceding clauses, wherein the representative mould cavity is a master mould cavity from which numerous female mould cavities can be produced.

Clause 20. A method according to any one of the preceding clauses, wherein the use of the female mould cavity to manufacture the plastic fittings is a use in an injection moulding process or a compression moulding process or a blow moulding process or a rotational moulding process.

Clause 21. A method of moulding plastic rainwater or soil fittings, the fittings comprising a cast iron effect finish on an outer surface thereof, where the method comprises: providing a female mould cavity having a textured inner portion representative of the cast iron effect finish, in negative form; and using the female mould cavity to manufacture the plastic fittings by injection moulding or compression moulding or blow moulding.

Clause 22. A method according to any one of the preceding clauses, wherein the female mould cavity is formed with at least one smooth-surfaced portion for forming at least one external jointing surface of the plastic fittings with a correspondingly smooth surface, which smooth surface does not feature a cast iron effect finish, and which smooth surface will contrast with the cast iron effect finish elsewhere on the fittings.

Clause 23. A plastic rainwater or soil fitting comprising: a cast iron effect finish on an outer surface thereof, and at least one jointing surface formed with a smooth surface, which smooth surface does not feature a cast iron effect finish, and which smooth surface contrasts with the portion with the cast iron effect finish.

Clause 24. The fitting of clause 23, wherein the smooth surface is relatively reflective, compared to the cast iron effect surface.

Clause 25. Use of a plastic fitting according to clause 23 or clause 24, wherein the fitting is joined to one or more other rainwater or soil fitting at the jointing surface, the jointing surface's smooth surface being fully masked by the one or more other rainwater or soil fitting.

Clause 26. A plastic rainwater fitting comprising a cast iron-effect outer portion, the fitting being substantially as hereinbefore described with reference to any one or more of the accompanying drawings.

Clause 27. A plastic soil fitting comprising a cast iron-effect outer portion, the fitting being substantially as hereinbefore described with reference to any one or more of the accompanying drawings.

Clause 28. A method of manufacturing a plastic rainwater or soil fitting comprising a cast iron-effect outer portion, the method being substantially as hereinbefore described with reference to any one or more of the accompanying drawings.

Claims

CLAIMS: 1. A plastic rainwater or soil fitting comprising: a cast iron effect finish on an outer surface thereof, and at least one jointing surface formed with a smooth surface, which smooth surface does not feature a cast iron effect finish, and which smooth surface contrasts with the portion with the cast iron effect finish.
2. The fitting of claim 1, wherein the smooth surface is relatively reflective, compared to the cast iron effect surface.
3. Use of a plastic fitting according to claim 1 or claim 2, wherein the fitting is joined to one or more other rainwater or soil fitting at the jointing surface, the jointing surface's smooth surface being fully masked by the one or more other rainwater or soil fitting.