Rock Molds-I don't get it.

More realistic. Conforms exactly to area. Lighter than real. Easier to manipulate than real.

This thread by @ED3945 who uses Bragdon molds to the highest level, will demonstrate why they’re used.

Ed3945 build thread

I doubt I could have done this without molds.

I’ve seen some people carve entire rock scenes in plaster, but it took months to do. I use Bragdon’s molds and resin. I can heat the castings and bend them over just about any shape I want. I do have a couple real rocks I use to place in scenes I haven’t got to.

I think that good rock molds look more realistic than what I could create by carving cast plaster or from other types of scenery base such as Mold-a-Scene, which is what what I sometimes use. Some rock molds are made by casting actual rock shapes into molds and look more natural to me than anything I could carve from plaster. As far as real rock, it's heavy, and I prefer to keep things lightweight on the layout .

MELGAR

I have a couple of molds but I also have used some real rocks.

Rock at bottom right is from a plaster mold. Top corner is carved rigid foam.

I had such a large area to cover that molds saved us a lot of time.

Another option is to carve Styrofoam with a hot wire cutter. This works well for smaller rock cuts. Takes some time if the space to cover is large. Results in a light rock face, which in my case, is easily removable to access the track and hidden wiring.  I have rock moulds, but have never used them. I am avoiding the mess or working with plaster. Nothing wrong with plaster, I am just avoiding it for now.

Walt at our club did a bunch of rock molds, and he used a bunch of real rocks as the pattern.  The real rocks weighted a LOT, and would have been a lot more cumbersome to work with.  Also, you can have a dozen of the same shape rock, sometimes that makes them easier to fit in than going to the creek and picking up random rocks.

@scott.smith posted:

Why is this necessary?

It's not necessary; in fact, very little is actually necessary.  Well.....dodging a wrench might be.

But they do tend to make far better rock outcrops, and mountain scenery than most people can make carving whatever materials you care to invoke.

Rock molds are in most cases easy to use, faster than carving and like GRJ mentioned, you can use the same mold over and over and just by turning it in different ways you would never know that it was the same mold and it was just blended into each other or into other rock molds.  They make for some really beautiful rocks too.,  Try them, you might really like them.

@railroad-guy posted:

I had such a large area to cover that molds saved us a lot of time.

Dan - nice rock work!

Scott,

I use Joel Bragdon's molds & cast satin.  The cool thing about Joel's system is that you can cut the rocks while they are pliable & create infinite variations.  The only thing that slows me down is my imagination.

I appreciate the posting of the Ed3945 thread. There is a lot to review & learn from him.

BTW Scott - I agree with those advocating rock molds and use them extensively myself.

Here's an option - the "rocks" shown below directly above the GG-1 were created with simple aluminum foil. First, you "steal" the foil from your wife, crumple it up, and then stretch it back to a reasonable shape, spay it with a wetting agent (plain water with a drop of dishwashing liquid), cover it with hyrocal from Woodland Scenics, apply it to the desired area, and then remover the foil before the hyrocal completely sets up.

Rock molds have saved me a lot of time, plus I’m not very artistic, so carving has produced less than realistic results. Here are some pictures of a layout I’m working on. Not done, but I’m happy with the progress thanks to the molds.

The first four photos are the area of the layout where I used Bragdon rock molds.  

The last two I used I used Cripplebush Valley Models rubber rocks. For smaller

areas I find them less of a hassle to work with and exquisite detail.

A combination of everything. Rock molds, carved Hydrocal, Sculptamold and carved pieces of foam.

Donald

For me it was molds from Bragdon because there are no rocks in The Netherlands but the molds from him are the best there is because you should not forget to look carefully at scaling down. Making rocks was not an option too much work for me and his molds were perfect of course with a lot of chopping I make also some. Real rocks are way too big for my job and neither fit nor realistic. I do this because I had a specific goal and can only be done with his molds and to scale. But everyone (railroaders) has their own way which is nice because it always remains a hobby. I have seen a lot layouts with beautiful rocks on O gauge Railroading Forum. The color is also very important I used 3 colors some 4 to make this.

There are some pictures some of them never was on this forum.