13. Molding and Casting

This week, I learned how to make a mold and use it to cast objects. I designed a 3D shape, milled it in wax, made a silicone mold, and then used it to create my final cast.

Understanding the basics

Individual Assignment

Positive wax mould

The first step in the process is to create a wax mould that will be milled with the milling machine. For doing this I have to create a 3d design to make a double sided mould. I am going to crete a toy bird.

To start with I reffrered to a youtube video to create this little bird. Link to the tutorial

I started by creating an offset plane above the base each at a 10 mm distance from the other. Go to Construct > Offset Plane.

To accurately sketch the bird, I imported an image of the toy bird as a reference. I placed the image using the Insert > Canvas option

After adjusting its size and position, I used the Spline tool to trace the outline of the bird directly on top of the image. This helped me maintain the proportions and details of the bird design.

Once the tracing was complete, I switched to each offset plane and created a circle at the same location on both planes. These circles would help give volume to the shape.

Then, I used the Loft tool to connect the two circles, which smoothly joined the shapes between the two planes. This gave the bird a soft, rounded 3D form—ideal for casting.

After lofting

Error: However, after lofting, I noticed that the body didn’t look symmetrical—the shape was uneven and slightly distorted. To fix this, I used the Split Body tool to cut the bird model in half along the central plane. I then deleted the flawed half and used the Mirror tool to regenerate the other side from the correct half. This gave me a perfectly symmetrical 3D shape, ready for molding.

Next, I needed to create a base to hold the silicone for casting. I created a rectangular box that would act as the mold frame. The box was slightly larger than the bird model, allowing enough space for the silicone to flow around the bird and form the mold.

I use the extrude function to convert the rectangle to a rectangular box around the bird.

Milling