Introduction: UV Faux Mushroom Platforms for Terrarium

About: I'm an animation director by day and Queen of the monsters by night. I picked up most of my costume and prop building skills through hands on experimentation with materials. Experimentation led to addiction,…

We'll walk through the building of that platform and discuss alternative designs for different types of animals.

*I have removed a chunk of my original Ible because I have now changed my tank set up to something more successful for hermit crabs, and didn't want anyone to emulate a sub par set up.

Step 1: Improvements: Mushroom Platform

I started to wonder whether I could make better use of the vertical space leftover in my tank. Sure, I gave them tall things to climb, but was that a cruel joke if there was nothing to climb TO? Was that like someone building me a house with stairs that go nowhere?

I decided to build a faux mushroom platform that the crabs could land on after climbing up. It gives them a place to settle, and I figured I can put treats up there as an incentive to use their climbing furniture. The look is inspired by those awesome glowing mushrooms the characters hop around on in the movie Fern Gully, if you're old enough for member that.

You Will Need:

Scrap cardboard

Scissors or craft blade

X-acto knife


Elmer's Glue

Crayola Model Magic

Mini Clamps

Rubber Tipped Scultping Tools or toothpick/ popsicle stick

Craft Acrylic (chosen colors)

Spray Clear Coat in matte or satin finish

Small Suction Cups or powerful magnets

Step 2: Sizing the Platform

Measure the side of your terrarium.

Since I have a hexagon tank, the width of my platform must be less than the width of each acrylic panel.

Mark out that width on your scrap cardboard.

Draw an irregular mushroom top shape within those bounds. For inspiration, google "amazon rainforest mushrooms".

Cut out the shape. Use scissors or a craft blade. The cardboard is just a skeleton for your final form, so your cuts don't have to be super elegant and precise.

Step 3: Mushroom Tiers

To create the growth layers of your mushroom, we'll retrace and size down our original shape twice.

Trace the original, hanging the flat edge off your cardboard.This will ensure your next layer is a little shorter than the first.

Look at your traced outline. Now loosely mimic the line 1/4 -1/2 inch inside the original. Your 2nd layer is now narrower than the first. Cut out the second shape.

Repeat by tracing the second layer. Make a shorter and smaller one based on that. Cut out this third shape.The smallest of the 3 is your third (bottom) layer.

STEM-- To make the stem of the mushroom, sketch a vertical shape based on the width of your platform. It can be short and stumpy or long and narrow, depending on your natural inspiration. Think organic, and don't worry much about symmetry.

Step 4: Safety Lip

I decided it might be a good idea to have a bit of a ledge on the platform. This will help hold treats on top and maybe (maybe) prevent the crabs from diving off the side.

Trace the original (largest) platform shape.

Mimic the traced line about 3/4 inch inward.

Cut out this thin strip.

Apply white glue to the ledge strip and apply it to the edge of your platform.

Clamp in place to dry.

Step 5: Assembly

You'll be assembling the mushroom growth rings in layers to get your overall cardboard skeleton.

Apply glue to the top of your smallest platform layer.

Press into place onthe bottom of the medium layer. Clamp to dry.


Apply glue to the top of your medium layer.

Press onto the bottom of the top layer. Clamp to dry.

You'll see them stacked logically and your mushroom form emerges.

When the platform chunk is dry, you can attach the stem.

Apply glue to the upper third of the stem.

Press onto the flat back of the mushroom chunk.

To ensure a perpendicular bond, you may wish to brace the stem against a flat object like a book (or a Pigs in Space lunchbox).

Step 6: Choose Attachment Method

My hope was to use magnets to support the mushroom, which would give this a totally natural, seamless look. However, after testing out several types of magnets we had at home, I found that none were strong enough to support the weight of our larger crab. The platform would just slide down the side of the tank like a one way elevator.

To get a secure, stationary bond to the tank wall, I decided to go with small suction cups. We'll see the tops peeking out in the end, but that's a small price to pay for a functional solution.

To create recesses for the suction cup heads, I started by tracing then onto the back of the stem. I placed one near each corner, for even distribution of support.

Cut out the holes using an x-acto, first tracing the outline of the hole and then using the tip to scoop out the cardboard piece.

The head fits snugly into the recess. We'll secure these with adhesive later in the process.

Step 7: Sculpting

I decided to use Crayola Model Magic to flesh out my cardboard mushroom skeleton. I chose it for the fact it is lightweight, and for the soft spongey texture that reminded me of a real mushroom. Smooth-On Free Form air clay was another good option I considered, but I ultimately decided against because it is a 2- part mix.

Start at the base of the stem. Apply a chunk of MM large enough to smooth out and cover your cardboard footprint.

Slope the MM up gradually, so that the stem meets the underside of the platform in an organic joint.

Using smaller pinches of MM, begin to cover the underside of your platform. Use your thumb to press and smooth as you go, keeping your application thin and true to all those nice ridges on your frame.

Continue until the underside is covered. Use your thumb to smooth out obvious seams of adjoining MM sections.

When the underside is complete, wrap MM up over the edge and begin to cover the top.

Keep your MM application on the top very thin, so as not to lose the definition of your safety lip.

Use small pinches of MM to cover edges and plump up the corners, making them flush with the back of the cardboard stem piece. DO NOT cover the back of the stem where your suction cup holes are. We want to keep this surface nice and flat, and adding bulk can only jeopardize that.

Step 8: Texture

This part was the most fun for me.

Use a rubber tipped sculpting tool to definite organic looking lines and ridges in your mushroom. if you don't have sculpting tools, toothpicks and popsicle sticks will do --they'll just make harsher lines.

I used the round tip to define the ridges on the underside and the flat tip to make the safety lip stand out more. The beveled edge of the flat tip was great for drawing ridges in the lip.

Vary your line work. Have some that don't wrap all the way around, and mix up the distance between neighboring lines. Press harder for deeper grooves and just barely brush for something subtle. *Note: MM is a little spongey and bounces back a little when you draw lines in it.

Texturize the top of the platform. This not only contributes to the natural look of the piece, it also provides ridges and grooves that will help the hermit crabs maintain a good foothold.

*Note on Dry Time: The Model Magic package specifies that the form will be dry to the touch in 24hrs, and fully dry after 72. Since our application was thin, I found it to be thoroughly dry and after 2 days.

Step 9: Painting

I used craft acrylics so that I could mix a custom color and give some detailing to my mushroom. If you just want to do a one color application, you could substitute a coat of spray paint for this step.

Look to nature for your mushroom color inspiration. I mixed a natural yellow/ khaki color to mimic the rainforest tree mushrooms I had in mind from the start.

Put down newspaper to protect your work surface.I used a scrap of my leftover cardboard as a paint palette for mixing my custom colors.

The second photo shows the ratio of yellow/white/beige I used to create my color. Yellow paints are often semi-transparent and require mixing with a bit of white to get opaque coverage, so keep that in mind if you choose to use yellow for your project.

Apply your base color with a sponge-type brush, almost dry brushing the color across the surface. This technique will prevent paint from pooling in all those nice lines you carved.

Add another squirt of white to your base color to create a highlight color. Dab this color on top of your platform where the mushroom would naturally be lightest.

Add a deep brown (I used Burnt Umber) to your base color to create a shadow color.

Use a paintbrush with a fine tip to apply shadow color.Accentuate the grooves along the edge, the rim of the safety ledge, and the lines on the platform and stem. Don't worry about being super precise. Varied line width and dappled color will contribute to the organic look of the piece.

Optional Black Light Reactive Layer! For the full Fern Gully effect, I wanted my mushroom to be able to glow.

Dilute a dab of backlight reactive acrylic with a transparent, matte finish. Apply with a brush to give a wash of florescent color to the platform.

I opted to dab back the excess liquid paint with a napkin before letting it dry. This gave my glowing areas a more natural, mottled look, rather than being a flat, artificial glow toy appearance.

When your acrylic is dry, apply a coat of spray of protective clear coat in a matte or satin finish. Something meant for indoor/outdoor that cites moisture proofing will be best for terrariums with humidity. Without a protective clear coat, your patin will peel and the cardboard may fall apart. Make sure to the hit the flat cardboard back, since that is still exposed.

Do NOT use a gloss clear coat. It will take away from the natural look of the piece and potentially make the platform more slippery for your critters.

*SAFETY NOTE:Execute your spray-on application in a well ventilated area, preferably outdoors. Use in a spray booth, or put newspaper under your work to protect the surface underneath.

Step 10: Suction Cups

The final step is attaching the suction cups (or magnets, if you have ones that are proven powerful enough to hold the weight of your pet).

I settled on a 2 part epoxy from Harbor Freight as my adhesive. My hope is that it will be the strongest and long lasting in a humid environment.

Mix equal parts of epoxy on a scrap surface.

Apply to the inside of your suction cup recesses using a toothpick. Dab in just enough to fill the holes to their brims.

Insert the heads of the suction cups into the recesses, which should still be a perfect fit. Hold here a moment to let the adhesive gel a bit.

Ultimately you'll want to leave your mushroom to dry on a flat surface, while resting on the suction cups. This is a good way to guarantee that the cups won't tilt while drying. I let the epoxy cure overnight before installing the platform.

Step 11: DONE!

The acrylic tank got its much needed makeover and the crabs got an "upstairs" room to enrich their playtime and foraging. I've been pleased with the performance of the suction cups and they actually aren't too intrusive on the illusion. The crabs figured out the up and down pretty quickly.

For slightly larger pets, like geckos, you may want to test out some high powered earth magnets as your attachment method. I have a similar faux rock shelf in my leopard gecko tank that uses quarter sized, super strong magnets to adhere it to the glass (like, super strong magnets that practically leap out of your hand). These will hold a 45 gram gecko with no trouble. Experiment and find out what's right for you.

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