Concrete Lego Bricks





Introduction: Concrete Lego Bricks

About: I like making stuff.

Awhile ago I watched a video of someone making candy lego bricks but they didnt interlock. I wanted to try the project and have the bricks interlock. I kept thinking about this project and ended up wanting to try it with concrete and not chocolate.

Step 1: Tools & Materials

1. silicone mix

2. concrete mix

3. sand paper

4. lego base plate

5. lego bricks

Step 2: Mixing the Silicone for the Mold

I decided to make my own mold for this project so I could make various sizes of lego Bricks. My mold holds one pound of silicone which is 16 oz. so you need 8oz of part a and part b. I accidentally did 16oz of both. Next mix the two parts really well so you will get a correct casting. I poured the silicone mix as high as possible to get the bubbles out. After all the silicone was in i tapped the edges to get the air bubbles to the top.

Let the mix try for 24 hours. Once it was dry the legos came out very easily.

Step 3: Mixing the Concrete

I used quikrete 5000 but if I did this again I would use a countertop mix because this one had a lot of big rocks. I separated the big rocks from the mix with a sifter. I added water to the mix and tried to get an oatmeal texture. Next I scooped a little bit of concrete and pushed it down into the mold. I used my hand but you should use a popsicle stick to really push it into the mold

Make sure to vibrate the mold to get air bubbles to the top

I used a base plate to put in the back of the mold to try to add holes so the bricks would interlock. You will want to weigh it down with a heavy object.

Let it dry 24 hours

Step 4: Sanding the Blocks

I honestly was surprised it even remotely worked. Some came out better than other but I'm calling this a success. I sanded some of them down and tried to build a tower.

Step 5: Enjoy Your Concrete Lego Bricks!

Overall, I am very pleased with how these came out. It was mostly an experiment to see if they would even work or not. I really wanted them to interlock like real legos. They sort of did but i think in the future if i spend more time leveling the mix in the mold then it would work better.



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    11 Discussions

    You can purchase Lego silicon cupcake molds at any lego store.

    1 reply

    I wanted to make my own so i can different sizes and put holes in the back.

    ROCKITE brand Anchoring Cement is a very good casting medium for craft projects like this. I use it for casting wargaming terrain and dungeon tiles. It has no large aggregates in it, blends to a smooth milkshake-like consistancy, is more durable, and doesn't have those tiny pieces of carbon that make it hard for paint to adhere, like QUIKRETE has.

    It does cost a little bit more, but the improvement in casting quality and strength is very much worth it.

    1 reply

    If you dip your molds into soapy dishwater right before pouring in the casting medium, the soap residue will help reduce the surface tension and make it easier to tap/vibrate air bubbles out of the nooks and crannies.

    1 reply

    that's awesome! Lego duplo would probably work great also

    1 reply

    To avoid the air bubbles, use a vibrating table.

    What are you planning for the concrete Lego? Are you building something special or just playing?

    1 reply

    I was just playing with them. I didnt have a set design when I made them.