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13. Molding and Casting: Cooper, Amalia, Elle

Group Assignment

Safety Data Sheets (SDS) - Elle Hahn

  • Review SDS for each molding and casting material.

Test Casts - Cooper Cumbus

  • Make test casts with each material.
  • Record mixing ratio, cure time, texture, and shrinkage.

Printing vs. Milling Molds - Amalia Bordoloi

  • 3D Printing: Good for complex shapes, but slower and can have surface issues.
  • Milling: Faster, smoother finish, but limited to simpler shapes.

Compare accuracy, time, material cost, and finish quality.

Saftey Sheets

These are the data sheets for the two casting materials we chose to compare this week.

Clear Amber

Property PMC™-746 Clear Amber
Type of Material Urethane rubber
Health Hazards May cause skin, eye, and respiratory irritation; harmful if inhaled or absorbed through skin
Precautions Use nitrile or vinyl gloves, goggles, and work in a well-ventilated area
First Aid - Skin Wash with soap and water immediately; remove contaminated clothing
First Aid - Eyes Rinse with water for at least 15 minutes; seek medical attention
First Aid - Inhalation Move to fresh air; seek medical attention if breathing is difficult
Flammability Not flammable
Storage Store in a cool, dry place with good ventilation
Disposal Dispose of according to local hazardous waste regulations

Smooth-Sil 940

Property Smooth-Sil 940
Type of Material Platinum-cure silicone rubber
Health Hazards May cause skin and eye irritation
Precautions Use nitrile gloves, goggles, and work in a well-ventilated space
First Aid - Skin Wash skin with soap and water
First Aid - Eyes Rinse eyes with water for at least 15 minutes; get medical help if irritation persists
First Aid - Inhalation Move to fresh air; seek medical help if symptoms develop
Flammability Not flammable
Storage Store in a sealed container in a cool, dry place
Disposal Dispose of according to local regulations

Task 8 Resin

Property Task 8 Resin
Type of Material Epoxy resin
Health Hazards Harmful if inhaled or skin contact; may cause respiratory irritation
Precautions Use gloves, safety goggles, and ensure good ventilation
First Aid - Skin Wash thoroughly with soap and water; remove contaminated clothing
First Aid - Eyes Rinse cautiously with water for 15 minutes; get medical help if irritation persists
First Aid - Inhalation Move to fresh air immediately; seek medical attention if breathing difficulties occur
Flammability Combustible
Storage Store tightly closed in a cool, dry place away from heat sources
Disposal Follow local environmental regulations

Sorta Clear Silicone

Property Sorta-Clear Silicone
Type of Material Silicone rubber
Health Hazards May cause skin and eye irritation
Precautions Use gloves, goggles, and work in a well-ventilated area
First Aid - Skin Wash with soap and water
First Aid - Eyes Rinse cautiously with water for several minutes; seek medical attention if irritation persists
First Aid - Inhalation Move to fresh air; seek medical attention if symptoms persist
Flammability Not flammable
Storage Store in a cool, dry, well-ventilated place
Disposal Dispose of in accordance with local regulations

Notes about Saftey

When using Smooth-On’s Smooth-Sil platinum silicone or PMC-746 urethane rubber, safety should be your top priority. Always work in a well-ventilated space so you’re not breathing in any harmful fumes. For both materials, wear safety goggles, long sleeves, and gloves—vinyl or nitrile gloves work best, because latex can actually stop the silicone from curing properly. Be careful about what surfaces you’re working on too—some materials like certain clays or untreated wood can mess up the curing process unless you seal them first. With PMC-746, extra care is needed. It contains chemicals that can be dangerous if you breathe them in or get them on your skin or in your eyes. Never heat it or spray it, and always use it in a space with good airflow. If it gets on your skin, wash it off right away with soap and water. If it gets in your eyes, rinse them for 15 minutes and get medical help. These materials are powerful, but they can be dangerous if you don’t handle them with care.

Testing Different Casts - Cooper Cumbus

On the left is the Clear Amber material and on the right is the Smooth-Sil 940. I think that the clear amber looks better since I double checked the mesurments and wasnt using materials that had been left out in the open for a long period of time

Comparing A Milled Mold to a Printed one - Amalia Bordoloi

Up until this point, our group had all made 3D printed molds so we just made a new mold for a wax to test with a different material. I made a duck mold based off this picture

Heres the final result of the milling:

Heres the process I went through while making it:

First I sprayed the mold to make it non stick

Then I mixed the two parts of the amber silicon together

Finally I poured the mix into the mold

The next day, this is what the cast looked like:

And heres what it looked like next to the 3d mold cast of the same material:

While the milled mold gave a smoother result compared to the 3d printed mold, it is easier and quicker to make and print a 3d mold. This is becuase you do not need to watch the mold be made with the 3d printer while I needed to watch a 40 minute mill for the wax mold.


Last update: May 31, 2025