14.Molding and Casting¶

Hero Shot of the Week¶

Summary¶

Group assignment¶

This week, we reviewed the safety data sheets (SDS) of our molding and casting materials, made test casts, and compared 3D-printed molds vs. milled molds.
Below is our complete documentation.

1. Materials and Safety Review¶

Epoxy Resin — Component A & B¶

We worked with a two-part epoxy resin system (Component A and Component B).
Before starting, we carefully reviewed the Safety Data Sheets (SDS) for both components.
Key safety notes:

• Wear gloves and eye protection
• Work in a well-ventilated environment
• Avoid direct skin contact
• Mix only at recommended ratios
• Dispose of material responsibly

Component B:

Component A:

2. Test Casting Experiments¶

2.1 Epoxy Casting – Chess Pieces¶

We created several test casts using clear epoxy resin, experimenting with:

• Transparent resin
• Pigment variations
• Decorative additives (gold flakes)
• Different curing conditions

Our goal was to evaluate surface finish, transparency, and bubble formation.

Results:

3. Mold Fabrication Methods¶

3.1 3D-Printed TPU Molds¶

We designed chess-piece molds and 3D printed them using flexible TPU filament.
TPU flexibility made demolding easier and prevented damage to the cast pieces.

TPU Printed Molds:

Advantages¶

• Very flexible → effortless demolding
• Low cost
• Fast to produce
• Works well for small casting projects

Disadvantages¶

• Visible layer lines
• Not suitable for high-temperature materials

4. Casting with Gypsum (Plaster)¶

To compare different casting materials, we also cast pieces using gypsum (plaster).

Mixing Process¶

We mixed water with gypsum powder until achieving a uniform consistency.

We poured the gypsum mixture into a mold that was previously milled.

Final Gypsum Cast¶

After curing, we removed the cast from the mold.

Summary:
- 3D-printed TPU molds are ideal for quick, flexible, low-cost mold fabrication.

Conclusion¶

During this group assignment, we successfully explored multiple molding and casting techniques.
We gained hands-on experience with:

• Reading and understanding SDS documents
• Working safely with epoxy and gypsum
• Creating both 3D-printed and milled molds
• Casting resin and plaster

This week provided essential knowledge for future Fab Academy projects and improved our understanding of materials, molding techniques, and casting workflows.

Individual Assignment¶

1. Designing the Mold¶

For my individual assignment, I designed my own mold in Onshape.
I created a negative cavity of the model and prepared a proper pour channel and walls for casting.

Onshape 3D Model:

2. 3D Printing the Mold¶

After finishing the CAD design, I printed the mold using PLA on a Bambu Lab 3D printer.

Once printing was complete, I cleaned the mold and prepared it for casting.

3. Preparing the Casting Mix¶

For casting, I used a cement/plaster‑type material.
Below is the dry material before mixing:

Then I added water and mixed until reaching a smooth liquid consistency:

4. Casting Process¶

I poured the liquid material into the 3D‑printed PLA mold.

After filling the mold, I left it to dry completely.

5. Final Cast Result¶

Once the material fully hardened, I removed it from the mold.
The final cast came out with some surface imperfections, but overall the details formed successfully.

Conclusion¶

In this assignment I designed, printed, and cast my own custom mold.
I learned how different materials behave during the casting process and how important mold geometry and venting are.
Next time, I will improve the mold finish and add better escape channels to achieve a cleaner surface.