Molding and Casting
This week I worked on the molding and casting assignment. As part of the group assignment,
we reviewed materials, compared mold-making processes, and carried out casting tests. In the individual
assignment, the goal was to design a mold according to the selected process, produce it with a smooth
surface finish, and use it to cast final parts.
Assignment
Group assignment
- Review the safety data sheets of each molding and casting material.
- Perform and compare casting tests with each of them.
- Compare mold fabrication processes.
Individual assignment
- Design a mold according to the process that will be used.
- Produce it with a smooth surface finish that does not show the toolpath of the production process.
- Use it to cast parts.
- Extra credit: use more than two mold parts.
- Extra credit: create your own materials.
Group Assignment
Digital platform used in the group assignment
As part of the group assignment, we used
BIOREGEN,
a digital biomaterials platform linked to REGEN, an initiative publicly presented as a Fab Lab Perú
project focused on promoting a regenerative economy in the Amazon. In addition, REGEN was recognized as one of the
winning projects of the Biodiversity Small Funds Initiative, promoted by the
Global Plastic Action Partnership (GPAP) within the framework of the
World Economic Forum and announced during the UN Ocean Conference 2025.
In this context, the project was highlighted for its work with Indigenous communities in Peru in the creation of
biodegradable alternatives from natural materials. In this activity, the platform was used as a support tool to define
the properties, ingredients, and preparation conditions of the biosilicone evaluated in the group practice.
Biomaterial test: biosilicone
As part of the group assignment, we carried out a molding test using a biosilicone made from
accessible ingredients, following a biomaterial recipe obtained from a biomaterials platform. The goal of this
test was to observe the behavior of the material during preparation, pouring, and solidification, as well as to
evaluate its surface finish and response when poured into a 3D-printed mold.
For this test, we used a group mold made by 3D printing, shaped as a
little Virgin with flowers. The mixture behaved well overall and produced a very satisfying
visual result.
Ingredients used
- 520 g of colapez glue
- 500 ml of water
- 50 ml of glycerin
- 15 drops of clove essential oil
Properties of the ingredients used
| Ingredient |
Quantity |
Function in the mixture |
Observed characteristics |
Handling considerations |
| Colapez glue |
520 g |
Main base of the biomaterial; provides body and consistency. |
When heated, it softens and helps form a homogeneous mixture; when cooled, it becomes flexible. |
It must be heated in a controlled way to prevent sticking to the bottom or burning. |
| Water |
500 ml |
Dissolving and binding medium for the ingredients. |
Helps hydrate the colapez and produce a uniform mixture. |
It should be added in the correct proportion to avoid a mixture that is too liquid or too thick. |
| Glycerin |
50 ml |
Plasticizer; provides flexibility. |
Improves elasticity and prevents the material from becoming too rigid or brittle. |
It must be mixed well to achieve a uniform texture. |
| Clove essential oil |
15 drops |
Aromatic additive and natural preservative. |
Adds a pleasant smell and helps delay the appearance of fungi. |
Used in a small quantity; added at the end or during controlled mixing. |
Preparation procedure
Before starting, we first measured water inside the mold to estimate how much material we would need.
Then we prepared the mixture with the corresponding proportions for this biosilicone.
To prepare the biosilicone, we placed all the ingredients in a metal bowl and heated them in order to
integrate them uniformly. The mixture was worked at approximately 70 °C, making sure the
components melted and gradually combined until a homogeneous material was formed.
As part of the pre-processing, before pouring the biosilicone into the 3D-printed
little Virgin mold, we applied a thin layer of petroleum jelly to the inner surface of the mold.
This step made demolding easier once the piece had solidified, preventing the biomaterial from sticking to the
mold and reducing the risk of damaging both the final part and the mold during removal.
Once the mixture reached the right consistency, it was carefully poured into the 3D-printed mold used in the
group test. Then the material was left to rest so that it could begin its solidification process inside the mold.
Material observations during the test
During preparation, the biosilicone showed a good ability to integrate all of its components. The mixture reached
a uniform texture and could be poured into the mold without major difficulty. It also adapted well to the geometry
of the model, allowing the shape to be reproduced successfully.
The final result was very positive, since the obtained piece had a pleasant appearance and an attractive visual finish.
Despite the issues during heating, the biomaterial could still be used without significantly altering its composition,
and the result was successful.
Problems encountered and how we solved them
During this test, an issue appeared during the heating stage. The mixture stuck slightly to the bottom of the container,
mainly because the metal container used was smaller than necessary and too much heat was applied at the beginning.
This caused part of the material to have more contact with the hot bottom before fully integrating.
To solve this, we controlled the temperature better and kept mixing carefully to prevent the material from sticking
further or burning. Fortunately, the issue did not significantly affect the final mixture, since the material continued
melting and kept its general properties. Thanks to this, the biosilicone could still be used correctly and the final
piece turned out very well.
Reflection on the test
This test helped me understand that, in biomaterials, not only the recipe matters, but also the heating conditions,
the right container size, and temperature control throughout the whole process. I also learned that small mistakes at
the beginning, such as excessive heat, can be corrected if the process is adjusted in time and the mixture is handled carefully.
In conclusion, biosilicone was an interesting material to experiment with during this week, since it allowed us to
explore a biomaterial alternative applied to molding and casting, with a satisfying final result both in appearance
and behavior inside the mold.
Bitter chocolate casting test
As part of the group assignment, we used bitter chocolate as the casting material to obtain the final
product from the molds previously made, both from the machining process and from the biomaterial process. The goal of
this test was to evaluate the behavior of chocolate during melting, pouring, solidification, and demolding, as well as
to compare the level of detail reproduced by each type of mold.
For this test, we used 594 g of bitter chocolate. The melting process was carried out using an
electric hot plate, a metal container, and a pot with water for a bain-marie,
which allowed the chocolate to be heated indirectly and in a controlled way. Through this process, the chocolate melted
gradually until it reached a liquid and homogeneous consistency suitable for pouring.
Once melted, the chocolate was carefully poured into the molds prepared for the practice, including the
commercial silicone mold obtained from the machining process and the biosilicone mold made as a biomaterial.
After pouring, the material was left to rest until solidification, allowing us to obtain the final little Virgin pieces.
During this test, the bitter chocolate behaved well as a casting material, since it melted uniformly through the
bain-marie method and flowed correctly inside the molds. This made it possible to reproduce the general shape of the part
and preserve the main details of the design.
My Learnings
This week I learned that the quality of the final result depends on the relationship between
material, temperature, mold, and demolding process. I understood that a 3D-printed mold can be a good
base for experimenting with biomaterials, as long as pre-processing, surface finish, and thermal control are considered.
One of the most important learnings was confirming that the biosilicone mold adequately resisted the
pouring of bitter chocolate, withstanding temperatures of approximately 70 to 80 °C without deforming
or losing the lines and details of the object. This made it possible to verify that the mold kept its shape, preserved
the definition of the little Virgin, and worked correctly as a container for chocolate casting.
I also learned that pre-processing is very important. Applying petroleum jelly inside the mold made demolding easier and
prevented the material from sticking to the surface. Likewise, I understood that even when a problem appears during
preparation, such as excessive heat or an unsuitable container size, the process can be recovered if the temperature is
corrected and the mixture is handled carefully.
Finally, this experience allowed me to compare two different routes in a practical way:
machining and biomaterials, observing how each one affects the mold shape and the quality of the final
casted product. Overall, this week was important because it helped me better understand the value of mold design,
material resistance, and reproduction fidelity in the final cast part.