>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. >>
Well, I am not sure about trucking that much river sand to the beach, but river sand is in fact different than beach sand. This difference is critical when selecting aggregate for use in my cast stone mixtures, because river sand is rough and jagged and provides much more potential for the mechanical interlocking of each grain of sand. This is important as the reconstituted stone matrix forms during hydration, when the mixture is setting up. Beach sand has been tumbled round and round against itself, the edges worn smooth by one of the greatest rock tumblers on earth, the ocean. The grains are much smoother and do not offer the same interlocking possibilities. Cast materials using this aggregate will break quite easily, and I would imagine that once the moisture in a sculpture is gone they would fall flat. I have often wondered about the longevity of such sand sculptures once they dry out! Best, Jim Tallman www.artisanindustrials.com [EMAIL PROTECTED] --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
