Casting is a manufacturing process by which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process.


Carve a block of wax to make a negative mold with the Roland Modela milling machine, use it to make a positive flexible mold with the Oomoo silicone rubber, and finally cast the piece with a dry stone solution.


The wax is tiny... so plan ahead the geometry you want to mill. In my opinion, as the process is long, it is always better to build a mold for a repeatable unit, so it can proliferate into a system. For this case, I chose a 3d tiling system with 2 different complex surfaces sides.

Drafting a (TINY) 3d tile system.

Proliferation (surface quads to smooth meshes).

Final tiling geometry A & B.

Final product


Sides A - free joint.

Sides B - solid joint.

Hard mold

If your piece is not squared, make sure that your PNG and your WAX BLOCK are alighed the same way: the Modela will start milling from the bottom left corner up. It has a short tool, so do not create deep and narrow pockets because it will not reach or it will destroy your mold walls! Also make sure that your STL is a mesh block and test it back and forth on the fab modules png maker before jumping into the milling.

STL file.

Map from STL to PNG (ROUGHING path).


Beautiful roughing path.

Map from STL to PNG (FINISHING path).

Finished wax mold (Took 2h in the Modela).

Flexible mold

Silicone rubber preparation 2 types -> OOMOO/PMC.

1:1 -> 70g each. Curation time 75min.

Flexible molds.

Casting dry stone

For the dry stone casting, I started with one sided piece production. Then transitioned to a two sided mold for a complete 3d tile.
How to avoid air bubbles: 1-when mixing the powder with the water, make sure you pour it in like if you were salting food, 2-pour the mixture slowly into the rubber mold, 3-vibrate the table arround it once pourred.

Dry stone solution. (20g water->100g powder)

Curation time 60min. (Don't forget to vibrate!)

Final one sided piece.

Two sided mold (low tech fixture).

Curation time 120min.

Final two sided piece.

Links to Resources

The wax blocks: LINK!

The silicone rubber: LINK!

The dry stone: LINK!