I will discuss the process of casting beginning with choosing a piece to cast, making the mold, and casting a piece from the mold.
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Step 1: Before You Start: the Setup
Time: at least 2 hours for a small project
-Nitrile gloves (NOT silicone gloves)
-4 paper cups for measuring
-2 paper cups for mixing
-paper or plastic cup to hold the silicone
-hot glue gun
-wooden mixers (popsicle sticks)
-something to mold
-urethane liquid plastic resin
-Ease Release agent
You should coat the surface that you're working on in a disposable material to catch any spills. It would also be a good idea to have paper towels on hand to clean up messes.
Necessary materials can be purchased from websites such as http://www.smooth-on.com/
Step 2: Molding: Choose and Prep Your Piece
Make sure that your piece doesn't have any nooks and crannies for the silicone to get stuck in; complex parts that cannot be lifted from the silicone will tear the mold.
If any of the components of your piece are loose, you may want to hot glue them together to prevent the silicone from shifting into unwanted places during the mold-making process.
Your piece should be rigid--a good rule of thumb for this kind of casting is that a soft mold like silicone should be used to cast hard objects while a hard mold should be used to cast soft objects.
Be aware that while your piece will probably survive the molding process, it might not. Do not try to cast anything unless you are okay with it potentially being damaged.
Step 3: Molding: Creating a Molding Container (Part 1)
Step 4: Molding: Creating a Molding Container (Part 2)
Step 5: Molding: Creating a Molding Container (Part 3)
Step 6: Molding: Mixing Your Silicone (Part 1)
Step 7: Molding: Mixing Your Silicone (Part 2)
Step 8: Molding: Mixing Your Silicone (Part 3)
In order to determine how much silicone you need, you can fill your empty mold container with water. You should completely cover the object that you're molding in at least half an inch of material. Be aware that you should wait for the mold to dry completely before pouring in the liquid silicone.
Your silicone will be composed of a 1:1 ratio of the two liquids. Therefore, pour half of the amount into a separate cup from each bottle. Different ratios produce different consistencies, curing time, and lifespan of the mold. Experiment or research this further if you'd like to know more about different ratios.
Step 9: Molding: Mixing Your Silicone (Part 4)
Step 10: Molding: Pour Your Silicone
To remove air bubbles, pick up your container and gently tap it against the table surface for about a minute. The bubbles should rise to the surface.
Step 11: Molding: Removing Your Mold (Part 1)
When the mold is done curing, carefully cut or peal away the cup. It may help to cut it away in pieces. Be careful not to damage your mold.
Step 12: Molding: Removing Your Mold (Part 2)
Step 13: Molding: Removing Your Mold (Part 3)
Step 14: Casting: Mixing Your Resin (Part 1)
This material is extremely irritating to the skin; be sure to wear gloves for this part. If you spill any on yourself, rinse it immediately.
Follow the same procedure as in the silicone mixing. Begin by opening the jars and stirring the liquid with separate popsicle sticks. Pour an equal amount of each into separate cups. Be careful not to cross contaminate the liquids.
Step 15: Casting: Mixing Your Resin (Part 2)
Step 16: Casting: Mixing Your Resin (Part 3)
Step 17: Casting: Pouring Your Resin
Pinch the cup and pour a thin, steady stream of the liquid into your mold.
Step 18: Casting: Wait for It to Cure
Step 19: Casting: Removing Your Finished Piece
Gently pull the silicone away from your piece and pop it out of the mold.