WIP - Large Stackable LEGO Blocks?


I’m looking for some help brainstorming construction methods for making large stackable LEGO(-like) bricks.

Functional - pieces interlock in a similar manner to LEGO
Colored - should be able to color or paint the blocks in various colors. Bonus if waterproof / water resistant.
Size/Mass - Variable - Should be able to easily lifted by one person. A standard 2x2 block should be at least 30cm x 30cm
Variety - Ideally similar to LEGO (e.g., some 1x2, 2x2, 2x4)
Quantity - Looking to make 25-30
Cost - The lower the better. Material costs <$10 / brick would be ideal.
Strength - primarily cosmetic. Ideally able to support several stacked blocks, but doesn’t necessarily need to support someone sitting on it, for example.

In the ballpark:

What I have so far:
Cardboard, either laser-cut or cut by hand using a template. Folded together or hot glued.
Molded from spray foam (probably 2 part to handle interlocking bits?)

Any ideas, however crazy, appreciated !


Caveat: this is just an idea, I have never tried this.

What about making the rectangular solid of the brick out of cardboard, and
vacuforming the mating sections out of a sheet of plastic?

You could laser cut the template for the brick, including cutting holes out
of the bottom for the recessed portion. You then stick a sheet of studs on
the top. For the bottom, the studs go into the holes that you’ve laser cut
into the bottom.

If you make the stud cylinders on the vacuformed slightly more conical they
should naturally nest.


I like the idea of a separate piece to form the top section - that definitely simplifies it.

Also like the idea of simply cutting holes in the bottom to allow mating. I was thinking way more complex.


Under category of crazy/impractical but may lead to something interesting:

make a custom, large format 3D printer


Clearly this is the right answer. Shave that yak!


Any reason not to CNC foam (styrofoam or that other stuff)? I imagine there will be a lot of demand for your new ballscrew setup once that comes online! But I think you’d need that kind of precision because lego depends on friction fit and my understanding of 3D printing so far is that that level of precision isnt really available in practice…unless you printed out of some sort of rubbery material with enough give…
Also, isn’t the 3D printer(s) at the space already big enough for that size ? The limitation I see is the amount of filament it’s going to take…expensive. There is filastruda.com , to make your own filament out of pellets which are much cheaper. But that machine is like $400 or something…


If you involve 3d printing more efficient to make this in pieces.

You can cut the block out of acrylic and assemble, then 3d print the circles at the top.

Even faster laser cut the circles as well and use methyl chlorine to bond them together. Cut small holes on the top plate and the circles to make aligning easy.

You can also use wood

PS Wood and acrylic pieces screwed together makes a really strong laminate. I’ve used this is some of support piece for my 3D printers and they do very well.


100% use eva foam, super light, structural, easy to cut and glue, you can even laser the pips out. Intuition Sports a few blocks south of the space will still you b grade 0.5" 5’x5’ sheets.