JoeDios.com Forums - View Single Post - Creating a Diorama with Trees and Rocks, step-by-step

So, we'll let the clay on the tree air-dry for awhile... now onto the rock face!

Our Rock Face Experiment

Now, we looked and looked for a casting plaster called "Hydrocal Light" but could not find it anywhere locally. So we fell back onto Plaster of Paris. Be careful with this stuff, it's quite toxic and can burn skin when it reacts with water. Hydrocal is supposed to be superior in every way... Plaster of Paris is mainly for pouring into molds, but as you'll see below, I tried using it a different way with mixed results ;-)

To start, we setup our rock face backing and used masking tape to hold in the crumpled up newspaper in place. The side closest to the camera will be a ledge for joes to hide on, thus jumping off wildly onto unsuspecting cobras below.

Mixing 2 parts plaster of paris, to 1.5 parts water, I dipped 3" strips of paper towel into the mixture, and then laid it onto the surface as shown below.

At this point, we're about 5 minutes in and it starts to harden faster that I was expecting. The paper towel edges are quite apparent, so I stick my hand in the bucket and pull some out to slap on the surface. This was working well until about another 4 minutes past... then it became clumpy and quite difficult to work with.

Ok, whew! We're finished for now. I'm not too happy with the clumpy look of the rock face. I think adding some plaster of paris mixture by hand at the end kinda ruined the smooth look it had. We'll let it set over night and maybe add some more mixture to it tomorrow to smooth it out. We'll see...

Cobra Commander standing on the rock face ledge... "With my authority, I claim this rock face Cobra Island!"

So there's some rock. Who knows what it will look like when we're done... a few misteps we think - but we'll attempt to clean it up later! Flying by the seat of our pants here! Woot!

Cheers! ~ Paul.

02-16-2008, 07:23 PM	#2
fifthconspiracy Smack-Talking Ninja Offline --> Posts: 581 --> Join Date: Jan 2008	Onto the Rock Face! So, we'll let the clay on the tree air-dry for awhile... now onto the rock face! Our Rock Face Experiment Now, we looked and looked for a casting plaster called "Hydrocal Light" but could not find it anywhere locally. So we fell back onto Plaster of Paris. Be careful with this stuff, it's quite toxic and can burn skin when it reacts with water. Hydrocal is supposed to be superior in every way... Plaster of Paris is mainly for pouring into molds, but as you'll see below, I tried using it a different way with mixed results ;-) To start, we setup our rock face backing and used masking tape to hold in the crumpled up newspaper in place. The side closest to the camera will be a ledge for joes to hide on, thus jumping off wildly onto unsuspecting cobras below. Mixing 2 parts plaster of paris, to 1.5 parts water, I dipped 3" strips of paper towel into the mixture, and then laid it onto the surface as shown below. At this point, we're about 5 minutes in and it starts to harden faster that I was expecting. The paper towel edges are quite apparent, so I stick my hand in the bucket and pull some out to slap on the surface. This was working well until about another 4 minutes past... then it became clumpy and quite difficult to work with. Ok, whew! We're finished for now. I'm not too happy with the clumpy look of the rock face. I think adding some plaster of paris mixture by hand at the end kinda ruined the smooth look it had. We'll let it set over night and maybe add some more mixture to it tomorrow to smooth it out. We'll see... Cobra Commander standing on the rock face ledge... "With my authority, I claim this rock face Cobra Island!" So there's some rock. Who knows what it will look like when we're done... a few misteps we think - but we'll attempt to clean it up later! Flying by the seat of our pants here! Woot! Cheers! ~ Paul.