Sunday, January 17, 2016

Rocks


Plaster of Paris is not expensive, it contains no formaldehyde or any of those odd things you might find in something like floor leveling plasters. Plaster of Paris sets up very quickly, and when it's dried hard, unlike so many of those floor leveling compounds, Plaster of Paris is not that flexible. It's actually rather wimpy. To make a slurry to pour Plaster of Paris into a mould the mix is 2 of plaster to 1 of water. The release for the mould is a drop or two of detergent in water. But there's something about moulded-ness that doesn't actually do it unless there's an issue of time and quantity of exactly the same thing.

A stiffer mix of Plaster of Paris dries very, very quickly indeed. Something like seven minutes on a cold day. But with a stiffer mix, 2 and a little bit more of plaster to 1 of water, you get a thick paste that can be troweled onto a damp surface and then you can scratch at it with pointy tools, stiff brushes, and if you're very lucky, and if you work very quickly, you can produce a couple of square inches of something that remotely resembles a rock formation. Then you have to worry about what happens when the plaster finally cures hard, the moisture gone from it.  It's been a couple of days waiting for that to happen.

2 comments:

Gin said...

Neat, neat, neat!!! VERY realistic! Hope it dries exactly like it looks there! Kudos!

tim candler said...

It's drying very white. I mean blinding snow white. Next step will be painting experiments?