Concrete LEGO





Introduction: Concrete LEGO

How to make your own 10:1 scale LEGO brick out of concrete!

You'll need:
  • 4 - 5 liters of concrete (when mixed)
  • Some scrap wood
  • Saw
  • Hammer and nails / screws and screwdriver
  • Ruler (or something else to take measures)

Step 1: Messure Up!

So, how large is a LEGO block?

These links ought to give us some clues..:

To make a 3 x 2 brick we get the following measurements:
Height of block: 9.6 mm
Width of block: 15.9 mm
Length of block: 23.8 mm
spacing of knob centers: 8 mm
Diameter of knobs: 5 mm
Height of knobs: 1.7 mm

To scale this up, we just change "mm" to "cm". Easy, huh?

10:1 block:
Height of block: 9.6 cm
Width of block: 15.9 cm
Length of block: 23.8 cm
spacing of knob centers: 8 cm
Diameter of knobs: 5 cm
Height of knobs: 1.7 cm

Step 2: Building the Frame

Remember that you want to be able to disassembly the molding box after the concrete has set, so dont go overkill with the size of the nails. (Or, just use screws instead)

1) Start out with a peace of wood that is approx. 18 x 26 cm and drill out the six 50 mm holes using a hole saw.

2) Nail another 18 x 26 cm peace of wood to the underside of the previous one.

3) Add the 96 mm high walls to complete the jig for molding.

Step 3: Molding

1) Follow the instructions on the bag of the concrete on how to make the proper mix. You will need at least 4 liters.

2) Fill the box up.

3) Why not add a copyright infringing logo to the wet concrete?

4) Set aside for a few days or what ever the bag of the concrete states, in order for the .

5) Carefully remove the box, starting with the sides and the "bottom".
To remove the wood with the six holes, its easiest to try to break the wood apart. Carefully.

6) If you chose to paint it, use the proper paint!
Candy red would probably look sweet!



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    I was surprised to see this as, for the past couple of months, I've been working on a seating project similar to this. We had a budget and lot longer for development (we also had copyright issues to avoid) But I thought people might like to see what we did. We had to consider durability, mass production and re-use of the molds. I have hundreds more pictures if anyone's interested. Obviously these look slightly different to actual LEGO bricks but they stack properly :)


    btw I did eventually get around to making this into a full concrete seating instructable.

    They look like those lego candie blocks XD

    Beautiful work. If they were rectangular they would be able to lock across blocks better/have more diverse use. Maybe make those in addition to these?

    Yeah, that would be cool. we didn't need the blocks to overlap for this project, but longer bricks would allow you to make more sound structures, if you wanted.

    There was a reply here I DID NOT POST (but it had my screen name). Anyone else have a problem with having their screen name hijacked?

    Your mold seems to have the same shortcoming that I noticed in the original. You seem to have the same spacing from the raised squares to the edge of the block as you have between the squares. If the outside margin was half the space between the squares, then you could stack your blocks in staggered rows, like a regular brick wall. Although it would mean you'd also need to make a mold for a half-size block if you wanted to make a rectangular wall, so maybe that's why you didn't do it that way.

    DUDE!!! I am going to do this to make a fire pit!!! I have been trying to decide how I wanted to construct it and I didn't see anything compelling. The custom concrete block design is awesome.