I created a realistic diorama of a waterfall falling into a green lagoon. It took a lot of effort and took several months to finish, but is very easy to learn how to do. This project is mainly intended for more advanced hobbyists or those with access to more expensive and specialized diorama-building products such are available from Woodland scenics.

Supplies

EPS or XPS foam from the hardware store or from packaging

Plaster of paris

Rock Molds either custom-made from latex rubber, or bought from Woodland scenics or other companies

Turf from Woodland scenics or other companies

Lichen from most hobby or floral stores

Clear resin from most hobby stores

Gloss gel from most hobby/artist supply stores

Sculpey for making the stalagmites.

Step 1: Creating the Shape

For this project, you re going to want to gather a lot of foam. This can either be EPS or XPS foam, either purchased from a hardware store, taken from packaging, or found in a dumpster somewhere. To create the base for the diorama I took an exceptionally big piece of dense foam and cut it to size with a sharp knife. To build the rest of the mountain I took pieces of foam and glued them together with hot glue to create a rough shape. Afterwards you will use a knife to carve away a more specific shape. It does not have to be too specific because a bunch of plaster rocks will be affixed to this, slightly changing the bulk of the structure and shape, so don't get too attached to its current shape. I did use a hotwire foam cutter for a lot of the building, but it is not a necessary tool at all, only a little easier to use than a knife and less messy. For the shape of my mountain, I wanted a cliff-shape in the front that the water flows through so I shaped it like that, but you don't have to. If you want to have a river flowing into the waterfall from the top of the mountain, will also have to carve away a section at the top for the river to run through. Remember that you will be pouring resin later on in the build, so make sure that the edge of the scenery is flush enough to add a dam. You will not have to worry about making it watertight because we will add plaster and sculptamold later on to seal all the cracks and make it safe for resin pouring.

Step 2: Adding the Rocks

For the rocky mountainside I used molds to make the rocks. There are a lot of alternatives to using molds, but molds are probably the most realistic choice. There are multiple ways to get rock molds; the most common way is to buy them from the hobby or model train store, but another way is to purchase latex rubber at the local hobby shop, find a rock you like, and make your own. A video tutorial for that can be found here; https://www.youtube.com/watch?v=Udd-rt26vY8 I used a mixture of the two for this project.

To make the rocks you will have to mix together plaster of paris and pour it into the molds. I had a bunch of plaster rocks left over from older projects I used to supplement. When pouring, it is advisable to dampen the inside of the molds with only a tiny bit of water so that the air bubbles that get trapped in the plaster when you pour it can be popped.

Once the rock castings are made, affixing them to the foam structure is easy enough with hot glue. I strongly recommend a high-temp hot glue gun for this; low-temp will not cut it. And if the gun is one of the larger-sized models with larger glue sticks it will be easier to use for this purpose as well. There will probably be times when the rock does not line up against the wall perfectly flat, or there are giant gaps between each rock in the wall, but these are okay since they can be filled up with extra plaster of paris to make it strong and to hide the gaps.

Alternatives to using rock molds can be to just use straight plaster on the foam, and as it is drying carve it with a knife to make it look like rock, https://www.youtube.com/watch?v=Ckn7gWsfyyU or to use the tinfoil method for making quick and cheap rock molds, https://www.youtube.com/watch?v=IaLpzNaVUaM or for carving the foam itself to look like rock. https://www.youtube.com/watch?v=zJU3w8UEUL0

Step 3: Applying Sculptamold / Plaster of Paris

Now that the mountain is beginning to look more like a mountain, it is finally time to smooth out all the rough edges and make it ready for the final steps. For this I am using two products: Plaster of Paris and sculptamold. Sculptamold is essentially a mixture of plaster and paper mache which is effective for building up thick, rolling groundwork, but most other paper mache products will work, and really it isn't necessary at all if you have enough plaster of paris and don't mind using that instead. Essentially what you want to do is to smooth out any rough patches and fill up any cracks with this stuff. You also want to coat anywhere where you will be pouring resin with a liberal coating of it. Resin disintegrates bare foam so you definitely do not want to pour it straight on.

Step 4: Painting and Applying Dirt

I usually like to add the resin before applying all the turf and foliage so that as the resin is drying no flakes of grass can get caught in it. But before the resin can be poured, certain areas should be covered with terrain so that the water can't trap any area that is unpainted, locking it away forever. So before I did anything else, I created the rocky beach below, painted the area where the resin will be poured, and painted some of the rocks as well.

Before pouring resin it is best to make sure the base color of the place you want to paint is not pure white. It should either be the same color as the water to blend in completely, or the color of dirt or sand to look like the bottom of the water. For this project I wanted the water to seem really deep so I painted it the same color as the water. For the area where the resin will be poured, I used two or three different shades of blue and mixed them together to imply shading; the shallower areas are in brighter blue and the deeper areas are in dark blue.

The shore area I wanted to seem like it was made of a bunch of small to medium sized rocks and pebbles. For this I found a patch of dry dirt near my home with a lot of differently-sized granules and almost-microscopic rocks. First you need to p;aint the area you want to apply the rocks brown; you don't need to do this if you want to paint the rocks after gluing them down as I will be doing, but it is just about necesary if you aren't going to be painting them later. This way the foam and plaster does not show udnerneath after the rocks have been glued down; and believe me, even if the entire surface is covered with rocks, you will be able to see a lot of the white plaster showing through if you do not paint it beforehand. After painting it, spread elmer's glue or whatever similar glue, usually called PVA glue, over the area you want to have dirt on it, and then sprinkle the rocks over it; then after it dries, blow, brush or shake off the excess into the trash or back into the bag for later. To make sure it has been adhered perfectly, use the same white glue and dilute it with water, then soak the whole area in the solution using a pipette, spray bottle, or whatever (make sure to dab away the excess glue with a rag or paper towel.) Then paint the rocks. I used a watered-down acrylic brown color, and drybrushed with a little antique white.

To paint the rocks, I used a medium grey acrylic paint, watered down just the tiniest bit so it could flow better; I then did a drybrush of antique white, and finally I covered it in very, very watered-down olive green paint. The result is a surprisingly realistic grayish-almost-green color.

Step 5: Damming / Resin Pouring

We are almost ready to pour the resin, but in order to do so it must be dammed very tightly, or else the resin will spill everywhere. For this I used a sheet of plexiglass cut very accurately on a tablesaw, but using a conventional saw will work fine. Really, lots of materials can be used to create a dam, such as popsicle sticks or even just tape, but for this project I wanted to make sure the dam was strong because of how deep the lagoon is and how much resin will be poured. I applied the plexiglass to the sides of the lagoon using hot glue and to make sure that there were absolutely no cracks, I took clear tape and taped all the sides firmly together so there was nowhere the resin could leak out of.

Then I poured the resin. There are a lot of tutorials for resin pouring and this time there was not very much different; so I will only say to look at those tutorials if you want. Resin-pouring is its own entire tutorial. But for here I will say that I used acrylic paint to dye the resin. The resin I used was Alumilite clear cast resin, and the package says to not use acrylic paint to dye it, and it is true that if you are trying to tint the resin a solid color using acrylic paint, the color will be inhibited (so that the surface is still slightly tacky or that the resin flexible), but that is only if you are using a whole lot of acrylic paint. For this purpose we obviously want the water to only be a little opaque, in fact the more you can see through it the more convincing it will be, so the amount of acrylic paint used here will not inhibit the cure enough to make any difference. Now during this project I made the extremely unfortunate mistake of using a little too much acrylic paint in the resin, so the water is way too opaque; but even at this level of opacity, the resin cured without any tackiness, so it just goes to show how much acrylic paint you can use to dye this particular resin.

Resin often takes 14-24 hours to dry, but this particular resin pour took much less time to dry because so much was poured at once; in addition, it was summertime when I poured this resin, and I poured it outside, so the heat and humidity in the air actually affected the cure; the overall cure time for this resin was approximately 8 hours. After the resin is poured, the plexiglass is removed. It can take quite some difficulty but it is doable, especially if you wedge a putty knife between the resin and the plexiglass.

The exact same process can be used to pour the resin for the river on top of the mountain. on this particular project, the river ran down the mountain at an exceptional angle, so what I did what tilt the entire diorama so the river lay somewhat flat before pouring the resin into it.

Step 6: Foliage / Scenery

And now for the final transformation; the part where the diorama comes to life. The application of foliage always takes a diorama from the unfinished stage way ahead into looking finished, even if the diorama itself still has several steps to go before it is done.

Most of the scenery I used came from model railroad product distributors such as woodland scenics and scenic express. Woodland scenics products can be found at any railroad store as well as hobby lobby and michaels, or on the internet, of course. To affix the grass was very easy, and was similar to how we affixed the rocks, right down to the application of diluted pva glue to fix everything even more firmly in place. The only difference is that beforehand I painted the ground brown to look likedirt and make sure that none of the foam or plaster shows through underneath. A lot of the trees on this diorama I used an advanced hobby product called Supertree which requires a bit of learning and experience to master. To get the product itself, one will likely have to purchase it online. A tutorial for using them can be found here; https://www.youtube.com/watch?v=iM9o_QiNkuI

For one of the trees in particular I used a dead stick I found on the ground and just stuck it in with some hot glue.

All the little ferns throughout the diorama I created with a fake plant purchased at a hobby store. I cut it up into little pieces and glued them all together in clumps of 4 or 5 throughout the model to create little fern bushes. To create the other bushes, I used generic lichen products found almost anywhere (even dollar tree!) and a few other products such as "bushes" available from woodland scenics, and little bits of the supertree, glued directly to the ground. The result should be spectacular. In the next and final step we will be creating the waterfall itself.

Step 7: Creating the Waterfall Itself / Finishing Touches

The waterfall itself is a dazzling, eye-catching part of this diorama. To create the waterfall itself I needed two products: Mod podge and liquitex gloss gel. If you don't have either of these products or want a simpler alternative, you can make a quick and dirty waterfall by dispensing hot glue onto a flat surface and peeling it off.

For the waterfall shown above, however, I found said flat surface (which for this project, was actually the resin lagoon itself) and painted multiple thick layers of gloss mod podge on top of it in straight lines tall enough to go from the top of the cliff down to the lagoon below. Once these several layers are dry a layer of liquitex gloss gel was applied on top. Here is where the shimmering effect is created; after applying the layer of liquitex gloss gel, blow onto the gel with a thick straw. It might get you out of breath for a bit, but it should also create some very detailed water-ripple effects. Once this final layer is dry, peel it off and apply it to wherever you want it. I made several smaller spouts of water personally. This method of making a waterfall, which I came up with myself, is one of the most incredibly beautiful I have seen, but the biggest problem is how fragile it is. It is so fragile that I would recommend never touching it. After about eight months mine broke and I had to repair it. To make it stronger I would recommend adding some kind of backing, or maybe reverting to the hot glue method I mentioned above.

For the finishing touches, I took a clump of poly-fill and teased out the fibers, then glued it to the base of the waterfall to create mist. Up close it looks a lot like polyfiber, but from a short distance it looks incredibly like mist. It's a really beautiful addition, but its also just as fragile as the waterfall itself.

Another necessary final step is to paint the sides of the diorama black to frame it all together and make it look finished, like a picture frame. I used apple barrel gloss black acrylic paint for this. Before painting the sides black, I made sure the sides were flush by using plaster of paris and sanding it down afterwards with a fine grit sandpaper.

Step 8: Bonus Step: Cave

This step requires a lot of work and extra skill, but it is an awesome addition to this piece. When I was carving out the shape of the waterfall in the first shape, I carved out a huge network of several holes in the back, two of which actually leads through tunnels out to two caves in the front, with the intention of making them caves. In the step wherein we added the plaster, I coated the entire inside of the cavern with plaster as well. I especially utilized the paper mache sculptamold material to give it a rough and bumpy, cave-like appearance.

As for the stalagmites,(the ones coming out of the ground and running along the walls) I sculpted most of them out of sculpey and left them to bake in the oven; others I created in 3d programs such as blender and tinkercad, and 3d printed. It took me a good deal of time and effort before I got good enough to make them, and scultping these could be a tutorial in its own, but what I would like to tell you here is that the main tools I used was my thumb and thumbnail to create the general shapes I wanted, with the little depressions in each level of the stalagmite wall, for instance, and a toothpick to make the thin little crevices in each layer of the stalagmites.

For the stalactites, (the ones that hang from the ceiling), I created some thin spikes in tinkercad and 3d-printed them, sticking them up through the plaster and into the ceiling and gluing them in place. The reason I 3d-printed them was because to get spikes that thin and that precise it is almost necessary to use a 3d-printer or some special material. I have tried before to make them out of sculpey, but they were too difficult. I did, however, use some toothpicks as stalactites to supplement my 3d-printed ones and those worked well.

I also added a grotto in one of the cave rooms, and for that I 3d-printed a bunch of candles I purchased on myminifactory.com. https://www.myminifactory.com/object/3d-print-candles-144705 Creating the caves took a lot of time getting into all the tight spaces, especially with placing each individual candle; I had to use a pair of tweezers to get them all in the right places.

To paint the cave, I first undercoated the whole thing in white. Then I used a caramel color from apple barrel over it. After that I spattered on different stops small splashes of very diluted red and green paint to get a big variety in color; after that dried I used very diluted brown paint over the entire surface to tie the colors together. Lastly, I took a special paint that dries entirely clear but has very fine glitter inside it, and drybrushed that across the surface to get that minerally cave-wall look. The result was very realistic.

Step 9: Diorama Completed!

And so the diorama is finally completed! It ought to take a very long time to finish, but once everything is finished you ought to be well on your way to making super-realistic lifelike dioramas. I hope you enjoyed this instructable and found it easy to understand, and I wish you good luck in any of your model-making or hobbying endeavors!