rock molds

Bill Pontin

Member
Have to give a little talk on my method of using plaster rock mold casting. Made up this little scene to show the method I use.
 

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Bill Pontin

Member
Tried a couple of different things here. First I read that the cork rail roadbed make great road shoulders. Came out rather good I thought. The road is sheetrock compound, great stuff since it can be lightly sanded when dry and then smoothed beautifully with a wet sponge. The grass in the forground I glued down a piece of felt fabric. The type you see in the craft stores sold by little squares. Choose a light tan color and glued it onto the foam. When dry I painted it with some laytex junk I had laying around, teased up the strands with a little wire brush, lightly sprayed on some adhesive and added ground Woodland scenic ground foam. Came out okay, too much work and the same results can be had with different textures of ground foam. (Other side of the road.)
 

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Bill Pontin

Member
The lines in the road are made with a white gell ball point marking pen. I use a piece of plumbing solder as a guide. It can be bent to contour the road and used as an edge to guide the pen. The pen I found will skip if the surface is too glossy. Still playing around with that. Note the lines are white, this is a typical 50's road before we went to yellow centerlines
 

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Bill Pontin

Member
love using the foam for the framework and support. It is so easy to cut and glue. Was using a latex foam adhesive but found that a hot glue gun works better and sets up so much faster. Youch, youch though, that glue does love to drip onto your fingers. Here is a four foot module I have started, this is the framework only. Will build the wood frame to fit later.
 

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Bill Pontin

Member
Few more supports and then I will start to cover with the plaster cloth. From there I will add the rock plaster castings. I plaster the back of the casting with a product called Sculptamold. Great stuff, something like a real fine paper machee (sp?) probably has some plaster and glue mixed in. Stuff adheres great, very slow drying so plenty of time to work it. It does take a good week to dry completely. Just about as hard as plaster but half the weight.
 

MasonJar

It's not rocket surgery
Nice Bill... Two tutorials in one! Can't wait to see the next part of the module construction.

Andrew
 

jimnrose

Member
Bill,
Great workmanship; thanks for sharing. I've been putting together rock formations. The progress has been slow but the main problem I'm having is getting the right color combination for the rocks reflecting the northeast. Any suggestions?
Thanks, Jim
 

Bill Pontin

Member
Thanks for all the encouraging comments.

Jim ~ There is so much literature out there you should not have any trouble locating a good source for methods and techniques. As far as rock color, with all the granite here, I think light grey would be a good northeast rock formation base color. With ideas from different sources and with practice I start by making a very watery wash of my base color in any latex or acrylic paint. Liberaly brush the mixture onto your rock castings. The watery mixture ensures that the paint will soak into the plaster and flow into all the crevices. This also ensures that you will not wind up with a patch of stark white plaster. Next using a more watered down mixture of black paint I generously apply this solution and before it dries I wipe off the excess thus exposing and highlighting the formation. I've also used an india ink solution as some do. I get the same results with the latex or acrylic paint and it washes off your hands a lot easier.

Now the hard part, accenting the formation. Hard in that you cannot envision the end results and think you are ruining all the preceeding work with each color you add. I use the cheap acrylic paints that come in the little 2 oz. bottles available in most craft stores. Using a 2" junk brush I dry brush different colors onto the formation. The key is using a very dry brush, swiping the brush and even jambing or jabbing the bristles into the formation. It was my wife, my strongest critic, that pointed out the use of purples, whites and silvers in coloring the rocks. I was sticking with the browns, and tan colors and when she dry brushed on the purple I thought everything was ruined. Wow everything started popping as she added more and more colors. Should point out that good lighting is also a very important ingrediant when coloring. Hope I was able to help somewhat.
 

sumpter250

multiscale modelbuilder
Bill,
I know you meant this as a rock building tutorial, but I really like the road. Using the cork as road shoulder, do you have the bevel facing the road, or facing out ?, and do you fill the roadway up to the level of the cork?
Nice looking scene!
Pete
 

jimnrose

Member
Bill,
Thanks for the great explaination. I started with light brown
(tan) and added the black wash and darker browns but the mountains looked like mid west & south west region. I have a large layout therby trying to form different mountain settings. The most difficult is simulating granite. This hobby requires almost all types of skills. That's both the good and bad news. Silmulating nature is a real challenge. Thanks again, Jim
 
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