One Technique, 5 Different DIYs: How to Make Super Simple Concrete Cubes

by on Feb 2, 2016

A gallon of something with crafting supplies around it.

Making ice with an ice cube tray is easy enough, but, did you know that concrete objects is nearly as easy? With a single silicone ice cube mold, you can make a variety of useful objects for the home. Read on for step-by-step instructions on how to do it!

The six-cube tray used for the projects shown here makes everything easy; no need to build a box or or cube form, because it’s already done! Bbest of all, the pieces come out of the mold with an incredibly shiny, finished surface, as if they were cast on glass.

ShapeCrete is our material of choice here, because it’s no ordinary concrete. There are no chunky aggregates (rocks) in the mix, and yet it’s strong and durable with a 10,000 psi compressive strength (which is way more than you need for these cubes).

It also allows you to create different mixes depending on your needs. You can make it clay-like toi make it workable by hand, or mix it to a pourable “casting” consistency by simply adding more water. ShapeCrete, when used as a “casting” mix, minimizes air bubbles and results in a very tight surface.

Here are a few easy projects that will help jumpstart your own creativity!

Materials

  • OXO or Similar Ice Cube Tray approximately 1-3/4” cubes
  • 3 lbs. ShapeCrete Mix
  • Rubber Gloves, Dust Mask, Eye Protection
  • Mixing Tub, Mixing Stick or Trowel
  • Water

How to Make a ShapeCrete Casting Mix

A person with light blue gloves mixes some cement in a blue container.

A person is wearing blue gloves as they mix cement in a blue container.

A person with light blue gloves mixes cement in a blue bowl.

Weigh out three pounds of ShapeCrete mix. Add about 1/2 cup of water to the mixing tub, and then pour in ShapeCrete. Add water in small increments and blend with a trowel or mixing stick. Continue mixing and adding water in small amounts until the mix has a fluid consistency. Avoid adding too much water as this can weaken the mix. It should flow off the trowel as you scoop it up. Watch the How-To Make a Casting Mix video for more tips.


Candlestick Holder

Concrete cube candle holders with candles on a piece of wood.

Materials

  • 3/4” Copper Pipe End Cap
  • Copper Cut Tacks
  • 3/16” Drill Bit
  • Cordless Drill
  • Duct Tape
  • Sandpaper
  • Modeling Clay

Drill a hole in the bottom of a copper pipe end cap and tape a cut tack in the hole. This will help keep the candle upright.

A person is drilling something on a sheet of particle board.

A person string to put a tiny copper nail into the top of a copper part with a drill and a can of paint in the background.

Man is gluing black cloth to the cap.

Sand the rim of the end cap to create a flat, smooth edge. Fill it with modeling clay, then stick it to the bottom of the form.

A man uses a stamp to drill a hole into paper on a plywood table.

A person holds two halves of an object.

A tray for making concrete cubes.

Pour in the ShapeCrete mix, filling it to the edge of the copper pipe. Allow the cube to cure for at least 48 hours. Remove your cube for the tray and presto you’ve made some cool concrete candlestick holders! Finish the surface to your desire. Makes great hostess gifts, especially if you monogram them!

A person wearing blue gloves is preparing simple concrete cubes.

A person working with cement while wearing blue gloves.


Tiny Cube Planter

ShapeCrete Planter Cube

Materials

  • Styrofoam
  • Clear Packing Tape
  • Spray Adhesive
  • Small Masonry Bit
  • Cordless Drill

Cut a 1-1/2″ cube out of styrofoam. Tape around the sides and fold the tape over like wrapping a christmas present. Spray one of the open sides with spray adhesive and stick it to the bottom of the form. It’s important to keep it centered because the walls are very thin and could crack. It helps to hold the foam with a screw and then place it into the form.

Pour the ShapeCrete mix around the styrofoam “knockout,” filling to just under the top of the ice cube tray. Allow the cube to cure for at least 48 hours. After removing the cube from the tray, carefully dig out the foam taking care not to crack the sides. You can drill a small hole for drainage with a 1/8” masonry bit.

Fill with soil and a tiny, sweet succulent and secretly gift a couple to your neighbors–brighten someone’s day! Or, create a tray full of them and make an outdoor or dining room centerpiece.

Cut the styrofoam into cubes

Tape the styrofoam

Spray one side of the styrofoam with adhesive

Use nail to hold cube onto form

Remove styrofoam from cured mold

Drill drainage hole


Paper Clip Magnet

A magnetic cube lying on the wooden floor on which several jump clips are stuck.

Materials

  • Horseshoe Magnet or Similar
  • Spray Adhesive

You can use any magnet for this, but it should be fairly powerful. A horseshoe shaped magnet will stay locked in the concrete cube, while shallow or cylindrical magnets may not remain in place. Glue the two posts of the magnet and adhere it to the bottom of the ice cube form.

A person putting together something near a gallon container.

Man spraying color to u shaped red color piece.

Blue concrete cube maker with magnet and other accessories.

Pour the ShapeCrete mix around your super-strong magnet, filling to just under the top of the ice cube tray. Allow the cube to cure for at least 48 hours.

Remove your magnetic cubes from the tray and enjoy making paperclip sculptures. Make a bunch of them and create an architect-worthy collection of magnetized building blocks.

A person fashions concrete cubes.


Herb Labels / Tablecloth Weights

Message paper is placing on the concrete cube holder.

Materials

  • 1/16” and 1/4”  Stainless Steel Cable
  • 1/16” and 1/4” Cable Ferrules
  • Alligator Clips
  • Wire Cutters
  • Pliers

We’ve recently become obsessed with alligator clips. And, well, cables with alligator clips AND concrete are genius since they become quite the utilitarian object around the house.

Here’s some key steps to making these nifty clips on cables. Start with a  sharp pair of wire cutters and pliers. It’s easier to work with 1/16” cable compared to a thicker, 1/4” cable, which is more difficult to cut. In either case, it helps to tape the cable at the point where you plan to cut so it doesn’t unravel. Crimp a ferrule on one end, which will keep the cable from being pulled out of the cube.

Use needle-nose pliers to crimp the alligator clip on the other end of the cable. Fill the mold with ShapeCrete casting mixture, wait a few minutes for it to firm up, and then sink the cables into the form. Position the cables to your liking and gently shake the mold, or smooth the top surface to even it out again.

A person is using a tool with a red handle to cut something.

Man bending a small piece of metal with a pair of pliers over a wooden work bench.

Man holding a pair of pliers and a thin piece of metal over a wooden table.

Instead of just one cable clip, grab a handful to make an array of them that emerge from the concrete cube. You can use a zip tie to hold a bunch of cables together, then just submerge them into one spot in the ice cube tray. Position the cables as you like. Gently vibrate the tray by shaking or tapping the tray which will settle most of the bubbles, or air pockets, in the mix and will smooth out the top surface.

Allow the cube to cure for at least 48 hours. Remove your handy-dandy, alligator clip cubes from the tray and create spontaneous signage / labels wherever you might need them. Even better, create an ever-changing gallery of your favorite pics–great for the office or home.


Tea Light Holder

ShapeCrete Tea Light Holder

Materials

  • Tea Light Candles
  • Masking Tape
  • Scissors

Ah, the ubiquitous tea light holder–here’s a simple solution to creating dramatic, albeit small, lighting for indoors or outside. We need to create a void in the concrete cube for the tea light to sit in. Simply put two tea lights together and tape around them with masking tape. Build up the masking tape until it’s about 1/16” wider than the tea light. Trim the tape on the bottom side and then put a piece of tape over the metal. Let the masking tape overhang on the top, this will keep concrete from getting into the “knockout” we’ve made.

A person is unrolling something near a gallon of paint.

guy cutting cubes with scissors

A person is cutting something with a scissor.

Man holding a small container with a white substance in it over a wooden work bench.

Concrete cubes set in a mold next to paper clips and small metal wiring.

Fill the cube mold about 2/3 full with ShapeCrete, then push the taped tea lights into the center of the cube. Allow the cube to cure for at least 48 hours. After you’ve pulled the concrete cube from the mold, replace the taped placeholder tea lights with new ones and enjoy some ambiance!


Casting and De-molding

(Removing from the Form)

Fill a small plastic cup with ShapeCrete casting mix and begin filling the ice cube form. Vibrate, gently tapping or shaking, the mold while filling the form will help to compact the mix and eliminate air bubbles. When the mold is full you can “screed,” removing or smoothing excess concrete, from the top with something like a ruler or a wooden stick. Cover the piece with plastic and allow it to cure for 48 hours.

Man wearing blue rubber gloves holding a concrete cube made from a concrete mixing bowl.

A person pouring cement into a blue mold.

Person is preparing a concrete cube.

Removing the pieces from the mold is a piece of cake…or like a cube of ice in this case. Gently pull all sides of the silicone mold away from the concrete. Pull on the middle dividers to break the seal on the inside, and then peel back the mold. With a little bit of careful prying, the pieces will release from the silicone tray.

Person is holding a concrete cubes in a box.

A person is preparing concrete using a box.

A person with blue gloves preparing concrete cubes.

A man with hand gloves is holding concrete cubes in his hands.

Concrete cubes being removed from a mold.

making concrete cubes


Finishing

Any sharp or uneven edges should be sanded with diamond hand pads, files, or sandpaper. The pieces can be left raw to develop a patina with age, or they can be sealed to help retain their smooth finish. Furniture bumpers or pieces of cork can be glued to the bottom of each cube to keep them from scratching other surfaces.

ShapeCrete can be colored with concrete pigment and concrete stain. It can also be painted, with a brush or a spray can. Rubber stamps can be used to create impressions on the surface, and you can even embed tile or stones to create a mosaic. The possibilities to add a textural element are endless. Check out ShapeCrete.com for tips on working with color, decorating your projects, and for new project ideas.

Sand any sharp edges

A cubical candle holder with an owl  on it, siting on a wooden surface.

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