If the intention was .....

.... to make a very light watch (which I believe it was) then why use AlSiC at all when other lower density materials are available? Yes, Richard must have in mind some other limits that are important to him in order to realise a case, and it would be interesting to undertand his personal limits for these further. Otherwise, why not simply use a polymer for this very extreme application? Ok, so it's hard to justify a 'Casio' case on a high-end watch, but if the intent was partly to keep a 'space/race tech' element to his choice, why not use Aluminium Beryllium ( I think even lighter in the 2.2 g/cm bracket)? What is the real driver to AlSiC? Is there a compelling case for it or is it just to be different?

Velociphile