Tool Review
Rock Mold
Rock Mold
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by: Scott Lodder [ SLODDER ]


When you need some rocks you have a few choices; nature, scratch build molds of various types, or pre-made molds.

I have used natural rocks and my own latex molds in diorama projects in the past. Each has its own unique advantages. With a current project I wanted to try another tool and technique to have a different perspective and another tool in my tool box.

That tool – is a pre-made mold from Woodland Scenic (WS).

What you get

You get a mold. That’s it. No instructions, guidance, nothing. Hopefully, the LHS that you frequent displays all the WS material together and you get the idea that the WS Lightweight Hydrocal is the material you should use with it.
Hopefully, the LHS employee can lend a hand if necessary. On the Woodland Scenics website there is help. There are pages that discuss the various products and how they are used.

The Mold

This is made of thick rubber and is very pliable. There is a large ‘lip’ area around the actual molding sections and the separate rock pieces ‘pits’ are nicely spaced out. Overall the mold is 10.5" x 5.5".

When you are purchasing these be sure to examine your mold before you pay or before you remove the packaging. While purchasing mine, I noticed another mold on the display that had a deformity in it. It had a hole that would make pouring plaster in it impossible.

The mold is dark black and on first examination looks ‘adequate’. The actual level of detail in the rock is hard to determine. All the molds in this line are the same overall size. Each mold in the series has a slightly different rock configuration. WS offers a suggestion for use such as river bed, or rock quarry, however you can mix and match as you see fit. Do a bit of research into the area you are modeling and pick the appropriate mold. While there is no hard and fast rule of which mold should be used for which application, there are some natural guidelines. Don’t use the sedimentary layered rock for a White Dover cliff.

Using the mold

Using the mold is straight forward, pour, pop, and paint.
The material is a nice rubber material and does not need any type of pre-treatment when using plaster. Just make sure it is clean and dry. Set the mold on an even surface. I used a few pieces of foam to keep it level during the drying stage.

I used WS Lightweight Hydrocal for my rocks you could use any plaster with this mold. You may even be able to pour resin in these – test it though. I used the instructions on the Hydrocal for mixing. I simply gently poured the plaster in the molds.

One point I’d like to make is that you should be careful not to over pour. This will save you in cleanup time.

Once the Hydrocal cured I popped the pieces out. The process for this was comfortable and easy. The heavy rubber mold makes it easy. You pry back the edges and push up from the bottom. Most of the detail is well molded in that there aren’t any aggressive under-cuts. These are where the plaster is ‘under’ the mold and you have to pull the mold out of the crease. All the pieces popped out of my mold with no problem.

Clean up is key for the next use. A clean mold will yield crisp detail. Use a stiff brush and maybe some water and towel to clean the leftover plaster.

End result

The resulting rocks are really quite nice. The detail and realism is quite good. Let the images speak for themselves. There are lots of nooks and crannies and realistic looking details.

I added two varying layers of hobby paint mixed to a gray color. Then over that I added some black wash, brown wash and lastly green wash. The topping touch is a white dry brush.

I am pleased to have this mold in my tool kit. I would not rush out and get one just to have. But I would buy another one when I need a different type of rock. It is cheaper than the latex scratch built mold and will last longer. It is simple to use and simple to clean. I would recommend that you purchase one, but when the need arises.
Highs: This mold is quick and easy, pour pop and paint. Its made of heavy duty rubber which should last a long time.
Lows: There are lots of options for rocks, which makes it a bit hard to add such a dedicated tool to your tool box. Not much in the way of documentation/instruction.
Verdict: I would recommend this and other molds if you have a bit of cash.
Percentage Rating
  Scale: Other
  Mfg. ID: C1243
  Suggested Retail: $8.79
  Related Link: Woodland Scenics
  PUBLISHED: Sep 08, 2007

About Scott Lodder (slodder)

I modeled when I was a teenager. College, family and work stopped me for a while. Then I picked it back up after about 12 years off. My main focus is dioramas. I like the complete artistic method of story telling. Dioramas involve so many aspects of modeling and I enjoy getting involved in the ...

Copyright ©2021 text by Scott Lodder [ SLODDER ]. All rights reserved.


Hi Scott, I saw these molds at my LHS last night,very tempting. I thought about several ways to use them,my biggest problem is I have a large creek running behind my house with plenty of free stone, pebbles,sand etc. The hobby store near me had several sizes,good price($8) and all the necessary goodies...Vince
SEP 08, 2007 - 12:54 PM
That's exactally why I didn't rate it higher - there are to many other options. If you do buy them they are good, may during winter when the snow and ice are hiding the real ones.
SEP 08, 2007 - 02:34 PM
Great to see a review of these molds. I have often thought of buying one or two. Natural rocks/stones where I live are usually round and looks nothing like these molds. Thanks Scott.
SEP 12, 2007 - 07:51 PM

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