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Week 13 - Completed

Molding and Casting

Assignment Overview

Group assignment: -Review the safety data sheets for each of your molding and casting materials, then make and compare test casts with each of them compare mold making processes
Group-Molding and casting

Individual assignment:
-Design a mold around the process you'll be using,
-produce it with a smooth surface finish that does not show the production process toolpath, and use it to cast parts

3D mold design

Steps to make a mold

1. Designed the Master Model

Design an object to mold and 3D printed it
Ensure surface is clean and smooth

2.Prepare the Master and Mold Box

Printed the mold box to be used
Clean the object and apply silicone mold
Put it on the flat surface to avoid imbalance

My mold is 3D printed, and below are the post processing done.
The mold pieces to post process

Tools used to smoothen the mold pieces

I used Rotary tool IDE grinder and sand paper to smoothen the mold

The video demostrates how the smoothening of the mold is done.

Before cleaning

After cleaning with water

3.Measure and Mix Silicone Rubber

Use a 2-part silicone rubber kit
Mix Parts A and B thoroughly with the ratio: 1:1
Stir slowly to avoid air bubbles

4.Degas the Silicone (Optional)

Use a vacuum chamber for 2 minutes
Let bubbles rise and collapse before pouring

5.Pour the Silicone into the Mold Box

Pour slowly from the opening stream
Let silicone flow around the object naturally
Tap or shake mold box gently to release bubbles

6.Cure the Silicone Mold

Let the silicone cure undisturbed for 4–24 hours
Time depends on product and room temperature

7.De-mold the Silicone

Remove mold box
Carefully extract the master
Trim excess material or flash

Molding post processes

Post-Processing on Silicone Molds

1. Cleaning & Flash Removal

Peel off any flash around seams.
Wash with warm soapy water.
Use isopropyl alcohol for stubborn residue.

2. Trimming & Detailing

Use sharp blades to clean edges.
Trim pour spouts and air vents cleanly.

3. Surface Conditioning

Apply mold release spray before casting.

Here I used cooking oil to apply on the mold

4. Inspection

Check for air bubbles or tears.
Ensure mold alignment and tight seams.

5. Test Cast

Use a quick material like hot glue or clay.
Evaluate detail capture and demolding.

6. Storage Tips

Store flat and away from UV light.
Avoid contact with sulfur-based materials.

Mold Ready for Casting

Apply mold release before each casting
Pour resin, wax, soap, or other materials, here I used epoxy in a ratio of 100:45g

Allow curing before de-molding the final part

The master piece and the Copy

Resources & Files

Master model Mold 3D print Post process video