Lifesabeach

Is there is a safe glue I can brush onto a surface so that I can sprinkle sand and/or fine gravel onto that surface? And also safe dyes to add to sand?

polkadotsmom

You can buy colored sand safe for aquariums- usually online.

I brush my rock with silicone (that I get at my fish store) and then sprinkle gravel on it)

Lifesabeach

Thanks for the tip.
I never thought of using silicone on the face. I applied a layer over some shaped polystyrene and applied sand over the face, and shook off the excess. I obtained an excellent sandstone effect.
Using different color sands carefully applied should produce veins and patches of different colors. I am interested in producing a dark background.
Once the sample dries, I need to test it in water to see how well the sand holds.

JRunyon21

You can use an epoxy resin. I put together a Styrofoam/Cement background a while back and 'sealed' it with an epoxy resin. While the resin was drying(which is fast) I sprinkled colored sand all over it. The sand I purchased from my local craft store. The sand really adhered to the epoxy and wouldn't come off unless scraped.

I also recently used the silicone method and came up with less than satisfactory results. I covered PVC pipes with silicone and sprinkled sand all over them and did not achieve the coverage I was looking for. A lot of silicone still showing and sand falls off easily it brushed up against anything.