Sand Sculptures: How do they do that?

I came across this page of sand sculpture pictures and was absolutely amazed. The sharp detail. The cantilevers. The arches. I wanted to see how they’re made. Do they use special adhesives in the sand? It can’t just be sand and water, can it?

I spent a while searching for information. I found this sand sculpture with stacked arches. Holy cow! And then a whole site full of phenomenally detailed sculptures which claims they’re made using only sand and water, and that they’ll last a whole year outside–even in the rain. I’ve seen one little rainstorm on the beach turn my carefully-sculpted sand castle into a pile of mush. With the details these guys use, it looks like a single raindrop would damage them.

Are they really made with just sand and water?

Yeah…and glue.

http://www.shadetreestudio.com/ss02.html#1

http://www.sandcastlecentral.com/contests/faq.html

A few things I note… First, a lot of those photographs are taken with the sky or other featureless background, so there’s no way to tell scale. Some things are a lot easier for a small sculpture than a large one. Second, there are a lot of artistic tricks used to make them appear more elaborate than they actually are: For instance, in the one of Apollo’s chariot, you’ll notice that the vertical sunrays are very long, but that the horizontal ones are much shorter, even stubby. Third, the self-supporting parts are stable shapes. In the sea serpent eating the sculptor, the serpent’s neck looks like it forms a catenary (the most stable curve for a free-standing arch), and the whole arch is wider at the base on both sides, and narrower on the top (the person being eaten is supporting the left side of the arch). Likewise, note that the sunflower lady’s hair has most of the weight in the thick, vertical part, with only a lightweight connection to her head (also note in the background of that pic a similar sunray trick to that used in the Apollo one). Some of the sculptures (though I can’t tell which ones) might also have odd proportions, and only look right from the particular perspective of the camera: The spider snail, for instance, might well have a much thicker support behind the web, that’s not apparent in that picture (I’m not saying that it does, just that for all that picture shows, it might).

Incidentally, isn’t that “Wizard’s Domain” one from a Dr. Seuss book?

Even with the compensations you’re talking about, Chronos, I look at something like the shovel in the sea serpent eating the sculptor, and I just can’t figure out why it wouldn’t collapse.

I think that’s precisely to what Chronos was refering. The shovel LOOKS like its separate and standing on its own, but it also looks very close to the serpent, so that I bet the shovel head, for instance, is actually part of the serpent’s head. I imagine there’s a gap between the thumb part of the hand and the serpent’s jaw, but I doubt there’s any gap along the rest of it. Still, skillful placement of the shovel like that, you probably wouldn’t notice that its the same block of sand even from another perspective.