The goal of this instructable is to make a full size 12" diameter cake mold, with a custom insert of a nyan-cat.
Nyan-cat was popularized in early april 2011, and features a kitten with a poptart stomach (or tummy, for short)
Further details on the glory that is nyancat are detailed here: http://en.wikipedia.org/wiki/Nyan_Cat
To create a cast cake mold, using the lost wax method, a wax positive of the required mold needed to be created. As a 12" diameter cake pan is too large to 3d print, and fairly complex to mill, a new approach was investigated: laminated lasercut LDPE,
Step 1: The Design & Lasercut Phase
Using CAD software, a 3D model of the mold was generated. With a full size model, a number of 1/8 inch thick slices were made and exported as drawing files to be read by an epilog laser cutter.
With the files <included> a number of 12" square plastic sheets could be lasercut. By stacking these sheets together, a full size model could be quickly re-built and used as a positive mold. For this mold, a lightweight, low cost, low melting temperature, lasercutttable plastic was chosen. LDPE fit the bill for these requirements, it even has the texture and flexibility of hot glue!
LDPE sticks together fairly well, with a hot-glue gun. Each layer was hot-glued together, while ensuring that edges and features had the lions share of the bonding. By gluing around the edges, it prevented the mold from having gaps which result in a poor final finish.