Hi Tony,
Yes, you are correct, some clay is the key to it. There are sandcastle
competitions every year here in Oregon at Cannon Beach. Every
sandcastler I've observed brings in buckets and tubs with a fair amount of
clay smearing on them. Just a few percent seems to do the job. Spraying
the surfaces to keep them just moist is the second important point. It is of
course not allowed to add clay to the sand, but there is no rule about how
clean your buckets, tubs and tools must be.
Best Wishes,
Edley.
Tony Moss wrote:
> Chris Lusby Taylor wrote:
> > As I recall from an article about a recent sand scupture competition in
> > Brighton, the secret is to use river sand, not sea beach sand. It is much
> > finer and, perhaps, its grains stick together better. Anyway, I'm pretty
> > sure no binding agent was used there. The results are amazing, particularly
> > where there are overhangs - jaws and noses, for instance.
> >
> > Chris Lusby Taylor
> >
> >
> >
> >
> An interesting explanation! I'd always understood that sand remains
> firm through surface tension of the water film around each grain when
> moist which ceases when it's dried out. Hence our feet sink into
> flooded sand when paddling near the shore ('plodgeing' for us Geordies)
> and also into dry sand but are supported on the surface when the sand is
> just moist. Would grain size affect this?
>
> Might it not be that river sand contains some clay particles as with the
> red Mansfield sand used in moulding and casting metals? This retains
> its compacted form even when dried out.
>
> Tony Moss
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