This invention is a "system" for building a mould for re-inforced thermosetting plastic products and concrete products, where in the desired shape is a curved surface that is smoothly changing in more than one direction, e.g. , boat hulls, curved pipes.

It has been found in practice that accuracy and fairness in large mouldings is very difficult to achieve. Current methods are to use large amounts of sand-able filler over wooden jigs, consuming hours of highly skilled labour time, fairing and filling.

This invention achieves the surface required by using very narrow polished interlocking planks of aluminium or plastic extrusion that slide together, as in drawing Figure 1. These are manipulated to form the curved surface over a framework of the desired shape. Another framework of accurately formed frames is built over, and fastened to, the back of the planks to form an accurate and solid moulding.

The object of the invention is to by-pass the "plug" (desired shape) making stage and go straight to a one-off finished product stage using a mould that has great accuracy and utilises very little in highly skilled labour time. A producer can test his product ideas and the market by-passing the need for a production mould until they actually have orders on the books.

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