Introduction: DIY Concrete Faux Geode Lamp

About: Welcome! Pleased to meet you, I am Barb; a Maker. I have been making things AND explaining how to make things for as long as I can remember. I was all about DIY before it was a popular term. I absolutely love …

Those geodes seem to be everywhere lately! They even appear as wedding cakes and cookies in sparkly sugar versions. But, myself I'm a practical gal and if I can make function part of a great design then so much the better! I had been racking my brain for a while to make a lamp design that is easy; as not everyone likes to 'play' with electricity. Success! This simple tutorial with many pictures shows how to make your own unique DIY concrete faux geode Lamp.

Step 1: Gather Your Supplies:

I had found some interesting results while working with my 'RapidSet Cementall and used those characteristics for my original design.

Tools and materials needed to make the form:

  • purchased lamp with simple shaft like Ikea Hemma
  • smooth plastic sheets (2) large enough for shape of geode (plexiglass, container lid...)
  • RapidSet Cementall & Water
  • container, mixing utensils, (hint: flexible plastic allows easy cleanup)
  • Dust mask, rubber gloves
  • Concrete reinforcing Fibers (optional)
  • Lighter/torch for burning off fibers
  • Emery cloth/sandpaper

Materials to finish:

  • Liquitex Acrylic Inks (black, white, silver, gold, copper, bronze)
  • Brushes
  • Glass 'Crystal Pieces' (made from glass pebbles)
  • Hot Glue (and gun) & Permanent adhesive (5-minute Epoxy, Gel Super Glue, E6000Clear Lacquer (nail polish) optional

Step 2: Set Up the Form:

Making the Concrete Shape:

The trick behind this easy tutorial is that there is no lamp-making in the process; as it uses a complete lamp.

You will be making the 'concrete shape' around the shaft so you will need to jig up a place that will position it slightly (2-5mm) off of the surface to allow the concrete to cover/encapsulate it. I'm using a tray here as it is shiny and elevates perfectly. You could just stack some things like books under your base. Secure it so it will not slide or move until it sets, packing tape works well.

Step 3: Mix the Concrete & Shape:

This RapidSet Concrete has a lot of 'flow' meaning; it will just flatten out. For this application we are not using a mold so it will need to be mixed of a thicker consistency to hold the shape. I find that last bit of mixing by hand works better here. Add a pinch of fibres if you have them. (maybe even small pieces of yarn would also work the same way)

Ya, I'm a problem solver..

This looks odd but what we are after is a rough edged shape with an opening in the middle. Play with the mix as it has quite the plasticity to it. Nature is not perfect, so make it random edged. Push the cement back into shape if it flattens. This concrete starts to set quickly so it will start to stay put.

Once you are happy with the shape, take the top sheet of plastic (preferably clear to be able to see through) and press it flat to allow good contact with the shape (some wriggling helps). If you want to adjust you can poke from the sides with some skewers.

Step 4: Ready the 'Geode'

I have been working indoors, so for clean up I just let everything set. Later I knock out the dried concrete into the wastebin.

After an hour this amazing RapidSet Cementall is set hard! The plastic will pop off easily...

and now you have your 'slice' of rock

Sand off, chip off any dangly pieces. The roughness resembles true stone in nature. I love how this concrete will yield a shiny finish if poured on a shiny surface.

The fibres can easily be singed off with a lighter or torch. Just don't light anything else on fire..

Step 5: Make the 'Crystals'

So, before you think I am crazy there is a reason for this! I had been thinking for so long about how to make 'crystals'. Growing crystals is not easy and they don't always last. Soooo, I did what I usually do, make them!

I threw a bunch of these flat glass beads in a cast iron pan (lid on just in case) and heated for a few minutes.

My idea is to shatter these. So slide them from the pan into some ice water and they will internally crack. Cool! Baked glass; who knew?!

I like the way that the glass breaks with a bit of a tap of a hammer. Just don't do it on the table or on the new kitchen counter! No, I didn't... btw. If you broke normal glass it would be too sharp and pointy. Marbles will also break, and you will have larger and smaller pieces.

Step 6: Paint Your Layers:

Adding the layers to the Geode Slice:

The messy part is done but it was super easy. This part is very therapeutic I find. Gather some nice acrylic metallic inks as well as some black and white. Inks are very highly concentrated with pigment so they provide a good amount colour with no thickness to the surface. You want this to be quite flat and shiny. The same technique as my geodes

Don't worry about your painting skills here. No need to fuss as some squiggles is perfectly fine. If you want some inspiration search pictures. I just follow wiggly layers from the 'hole' shape. Vary them in colour and width, use a nice fine brush.

Step 7: Add Your Crystals:

The metallics offer a great catch of light so I like to use them the most. Finish off the edge with some antiquing. I did paint both sides but they don't perfectly have to match since only one can be seen at a time.

Adding the crystals to the center:

Once you have made your crystals by baking/shocking (as in my previous geode post) you are ready to adhere.

When it comes to a adhesive I did a test. The Super glue works well but it has to be a perfect matching surface. The E6000 works well, but will set after a few minutes. The Shoe Goo is similar but has too much 'rubberiness' and takes even longer to set. Since I have a LOT of crystals to attach I like FAST SETTING!

I use a hot glue to set with minimal amount of glue. I will make make it more permanent later on. The 'pebbles' will have some round edges that I like to conceal.

Work your way around. Smaller pieces will fill later...

One of the strongest glues I use is 5-minute epoxy. It sets clear and fast! Mix up small batches and drizzle over the seams. This will make the bonds permanent. Ok, I am a bit of a perfectionist so for even more realism sprinkle some small pieces into the epoxy.

To make the edge less obvious add a bit of the paint/ink. If you are worried about little fingers or sharp edges you could give it a coating of lacquer (clear nail polish) to round off the edges. I have made quite a few of these now and the edges are not as sharp as the 'broken bottle' kind.

Step 8: Enjoy Your Lamp!

Are you not amazed how a hunk of concrete can look?! No whimpy styrofoam here. Looks like stone, feels like rock...

You are all set to use it and no wiring to do before connecting. I must say; it's one of my favourite projects as it has a function as well as beauty and you can use a colour palette of your choice without having to hunt for any rocks. Real ones can in $1000's!

I know your friends will be dazzled! If you like this you would probably like some of my other unique concrete designs:

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