#  Casting 

 



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 ![mold.jpg](/sites/g/files/omnuum4601/files/srtdesigncomp/files/mold_4.jpg)

 

**Step 1. Design and Create a Mold**

Design and create a mold, making sure to think about the mold as an inverse of the final product. A mold can be laser cut from acrylic sheets and glued together with a super glue (we used Zap-a-Gap).

**Step 2. Prepare Everything Necessary to Pour**

Once a mold is created, the tools and materials needed to mix and pour the silicone robot must be prepared before starting steps 3-5. Some silicone mixes like the Ecoflex-50 (15 mins.) will start to set quickly. Preparing all tools and materials ahead of time will allow one to properly finish the mixing and pouring stages.

**Step 3. Mix The Silicone**

Once the materials and tools are ready, measure and pour an equal volume or weight of part A and B of your silicone kit. The Ecoflex-50 and Dragon Skin use a 1:1 mix ratio by weight or volume. Make sure to follow the directions provided on the packaging. Different silicone kits may have different instructions on how to mix their brand of silicone. The best mixing technique is one in which the silicone is slowly and steadily mixed for a short period of time. Overmixing can cause air bubbles and popping to occur when actuated. Pigments should be incorporated during the mixture of part A and Part B.

 ![mixing_silicone.jpg](/sites/g/files/omnuum4601/files/srtdesigncomp/files/mixing_silicone.jpg)

 



 

**Step 4: Pour the Silicone Into the Mold**

After the silicone parts have been mixed, slowly pour the silicone into the mold. Evenly spreading the silicone with a long straight strip of rigid material will allow for an even thickness. The edge of the mold can be used to guide and get rid of any excess silicone. Allow every poured silicone component to fully set and cure before peeling. Curing times may vary on the brand and type of rubber silicone being used.

 ![pouring_.jpg](/sites/g/files/omnuum4601/files/srtdesigncomp/files/pouring_.jpg)

 



 

 **Step 5: Peel and Assemble**

Carefully use an X-Acto knife or blade to peel off an edge from each mold. Manually peel the rest of the silicone from the mold. Be careful not to pull too hard as it might tear thin areas. Trim excess pieces of silicone and set aside each component for assembly. Use the Ecoflex-50 and a syringe to assemble and glue down the components. Gently press down on each glued down layer to get rid of air bubbles created in between. To prevent silicone layers from sticking together, Vaseline may be lightly spread where air chambers are located. Make sure to not spread any Vaseline were silicone will be used as an adhesive. The silicone may not cure properly.

Allow for your soft robot to fully cure before actuating. Silicone used to glue components together may take longer to set and cure.

 ![peeling_and_assembly_01.jpg](/sites/g/files/omnuum4601/files/srtdesigncomp/files/peeling_and_assembly_01.jpg)

 

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 ![peeling_and_assembly_02.jpg](/sites/g/files/omnuum4601/files/srtdesigncomp/files/peeling_and_assembly_02.jpg)