Jack Aubert wrote, >I have been wondring how hard it would be to cast a dial out of concrete....
>...Has anybody tried this? It should be possible to get something that looks >somewhat like stone without the difficulty of stonecarving. Although I haven't seen it for some years there is/was an excellent product called CimentFondu - a high-alumina fine-grained product which is excellent for casting. If cast in a smooth mould the resulting dark surface could be mistaken for patinated bronze (at a distance) and should be excellent for dial making. I remember it being used as a cheap bronze substitute for casting life size figure sculptures. It has one major problem which may account for its reduced usage i.e. unless the mixing is done with the exact amount of water specified by the manufacturer it will 'rot' in time and simply return to powder. At least one new school in Northumberland had to be demolished and re-built because one-site mixing for structural elements wasn't properly supervised. As with many casting processes entrapped air bubbles can be eliminated by pre-coating fine detail e.g. with a brush before final filling of the mould. Vibrating the mould/mix while filling is essential. Tony Moss
