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Week 13 - Moulding and Casting

Group Assignment :

Review the safety data sheets for each of your molding and casting materials.

This week we used the following molding and casting materials:

Aditya Silicone Rubber RTV – 1010

Datasheet: Aditya Silicone Rubber RTV – 1010

Aditya PU 3 Minutes Cast Resin Milky – 555

Aditya Ultra Clear Cast Epoxy – 37

Silicone Rubber RTV – 3434

Mould Releasing Spray 1083

PU ( Polyurethane ) Rubber – PU40

Safety Precautions.

Refer to the safety data sheet if available for more specific safety measures. Since a proper document was not available, we follow some general practices when working with all these molding and casting materials.

  1. To prevent contact with skin, always wear gloves when handling silicone. In case of physical contact, wash with soap and water
  2. If there is any leftover mixture, use it completely in dummy molds and let it cure. Once cured, silicone is inert and is safe to handle
  3. Use a dedicated space for handling chemicals like silicone and resin to contain any waste produced to one location in the lab
  4. Segregating chemical waste to be handled by relevant disposal team.
  5. Avoid eating or drinking near the molding & casting workbench
  6. Store chemicals in a cool, dry place away from sunlight.

Make and compare test casts with each of them.

We have a seperate workbench dedicated to molding and casting to make it easier to clean and manage spills and waste. .

First we measure the amount of liquid that will be required to fill the two molds using water and pour it into a cup. Then, we mark the liquid level using masking tape.

We then dry both the cup and the mold using air blow gun, place it on top of the weighing scale and zero it. We then add silicone upto the same level as marked previously using the masking paper and check the weight of the silicone.

We then add curing agent according to the ratio specified on the bottle.

Now we mix thoroughly. Care must be taken to mix thourougly but slowly in a front-and-back motion instead of a circular vortex motion to avoid adding air bubbles

We also use a vaccum pump to remove as many air bubbles from the mixture as possible

Once done, we pour the mixture into the mold slowly, let it drip in thin threads to avoid air from getting trapped in between while pouring. Additionally, I tap the mold several times once pouring is done to ensure that air is not trapped inside.

As an additional step, we tap the the mold multiple times on the ground to bring an trapped bubbles that remain to the surface. The heat gun is used to pop these bubbles

This is how the mold looks like once all this is done.

Now we wait 24 hours for the silicone to cure. Once cured, we carefully peel the silicone out of the wax mold

We repeat the same steps to make test casts out of resin.

We use mold release spray to make it easy to remove the cast once cured.

We used paint to add colour to our casts

This is what they look like after 24 hours

Compare mold making processes.

Last update: June 19, 2025