Layered Rock Mold

[eTraxx]

I poured layers of plaster which I broke and stacked to make a 'shale' rock face. Made a latex mold of that. It came out pretty good I think.

Close-up of the 'plug'. I sprinkled baking soda into the crevices and used a thin super-glue to fit it. Larger spaces were filled with some Sculpey


Here's the mold on top of the plug with a painted casting. The car is 1:50 for reference


Close-up of a 1:48 car alongside the plug


another of a 1:50 car alongside the casting


.. and a close-up of the casting. Not satisfied with the coloring but the layered rock effect I am pretty happy with.

[Craig_H]

Ed,   I like the layered rock effect  wouldnt mind haveing a couple of those casting   Craig

[artizen]

Thanks for sharing this. I have been looking for a way of creating more realistic Welsh slate drystone walls for a while.

[eTraxx]

Ian. Was thinking. You know there was the thread on making the cracked-asphalt where I embedded some wedding-veil material in some thin plaster. I'm thinking .. if you made a plug that was longer and much thinner (like3/16" thick let's say) .. you could glue the casting to something flexible like the wedding-veil material .. and you could end up with a flexible 'wall' that you could put where needed. I'm betting that it would break at the 'joints' between the individual 'stones'. I'm going to try it .. see what happens.

[eTraxx]

After discussing the mold with Ian I was looking at the mold .. and had an Epiphany .. or could have been gas .. but .. why not use the mold .. fill just the bottom of it and slap in some weddin-veil .. !!!

.. a little plaster and some wedding-veil


the result after breaking it along it's length ...






.. and is flexible so could be bent to fit

[Malachi Constant]

Much better!  Shale is really crumbly and there's never rarely a neat, vertical, straight cut of it ... whatever breaks loose will add to the effect.  Also, shale that I see in Western Maryland and West Virginia often has ground water seepage  ... damp spots ... sometimes the equivalent of a little 'spring' in the rock face ... and there's usually enough loose soil with the loose rock to allow a fair amount of plant growth in and around the rocks.

Also, consider that the layers are often tipped a bit off the horizontal ... so consider mounting the casting at a bit of an angle to avoid the "horizon look" in your shale.  Looking good ...

Cheers,
Dallas

[chester]

Nice effect Ed, thank you for the tips.

[artizen]

OK Ed, I get the bit about curving the thinner wall around a corner but can it also handle going up a slight incline as in real life? I would assume you would just break the wall to achieve an uphill and just dodge in the details afterwards with more loose shale bits? You know what I mean - the wall follows the contours of the land in a vertical direction.

The end result you have achieved so far is quite realistic and simple to build - my sort of modelling.

[eTraxx]

Ian, it bends in all directions. I just took the casting with both hands and pressed with thumbs to break it up. The cracks run horizontally and vertically. I just went and took a couple of pics. One I have the casting bent vertically almost into a half-circle. You can see that it just opens up the space between the horizontal strata. If you bend it the other direction so the face is concave it will bend less so, until the layers touch but you could 'fix' sever bends by doing what mother nature would do .. break it! The other photo shows me twisting the sucker.

This test run I just dipped the wedding-veil material in some soupy plaster and plunked it onto the top of the casting while it was wet. I think that a thin layer of plaster applied at that time to embed the material .. gauze would work too .. into the casting would be better. The other thing you might want to try is to 'glue' your flexible material onto a dry casting. A flexible adhesive .. white glue? silicon?

Was thinking. You want to use the technique to build drystone walls. Instead of what I did which was an attempt to portray rock strata, you could just take the sheet of plaster and crumble it up. That way you would have a pile of 'slate'. When I made my plug I stacked the horizontal strata like I was building a wall. Used some wood to make a three sided box to hold everything (more or less) so I got a vertical back to it. You could do the same with your pieces of slate .. just build the wall. I used regular scenic mix of white glue and water to bind the thing together. One thing that seemed to work pretty well was using the baking soda. I was concerned with the cracks and spaces between the layers of plaster .. in that the mold would seem between the cracks and lock the mold into the plug. I simply flipped the plug over on it's back after the cement had hardened and sifted the baking soda over the face. I brushed it into the cracks and then off the face with a brush. Finally took thin CA (super glue) to bind everything. I used some flat clear spray in an attempt to seal everything. Seemed to work.

[artizen]

I'm thinking now. Once I get out of therapy after building all my walls and gate posts and buildings with individual bricks (I blame Nick Ogden for this fit of insanity) I will investigate this technique. Your thread has been bookmarked for future reference!!!! Thanks for the help.