Molding and Casting

Sphere Pedestal

Casting creates smoother surface and finer features than 3D printing. There’s lots to know about the properties of the different materials, e.g. alginate gel can be used to mold body parts. Note that most materials are not food safe, i.e you couldn’t cast a cup.

A video posted by Raphael Schaad (@raphaelschaad) on

Machining the Wax Block

Weʼre trained on a ShopBot Desktop CNC mill. In contrast to the 2.5D paths we did on the large router, we will do 3D paths on this mill, which requires the ability to simultaenously move the spindle up and down on the Z axis while moving on the X or Y axes.

The ShopBot is hooked to a Windows workstation (mas865/FabClass15). PartWorks 3D on it reads many 3D file types including of course .stl.

This tutorial from 2012 is a helpful step-by-step guide on how to mill the 3.5x3x1.5" blue machinable wax block we’re given. When following these instructions, ensure they’re still current. (Here’s another milling tutorial from 2013.)


Casting the Silicone Mold

We use OOMOO® (blue silicone rubber) to create the mold, on which there’s a good tutorial from 2013.


Casting the Object

We use DryStone (white and smooth, like gypsum) to cast the object, on which there’s a good tutorial from 2013.



I’d like to cast a solid life-size head with USG Hydro-Stone® (grey and strong, like concrete) and use it as headphone stand on my desk for my Bose QuietComfort 15.

I used to do a lot of bronze casting with my dad and at some point I’d like to get back into metal casting. Here’s a tutorial from 2013.