Silicon mold for food and ice

Forming and modling

Used tools, methods and technologies:

  • Sillicon 940, foodsafe, Smooth-On
  • Plexi glass, hot glue
  • Original object, 3D printed mold

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     This week I tried creating a foodsafe sillicon mold. I did it with basic home tools and sillicon kit from the Smooth-On manufacturer.

     I used exactly Smooth-Sil 940 Platinum cure silicone rubber. It has pot life, meaning time to work with it, around 30 mins and cures for 24 hours.

     I used wooden board as a base and glued my originals to it. Then I builded my mold frame around them with cca 5mm of tolerances. I strongly recommand using smooth wood or a plexi glass as the base, because I had issues with detacing the silicon from the rough wood board afterwards.

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Mold frame from wood, plexi glass and hot glue. Originals secured using hot glue.

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Part A of the silicon

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And the B part, in mix ration of 100A:10B

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Silicon poured, now wait 24 hours. Its actually fine to wait around 5, but it depends on the size of the mold

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     I used a wooden stick to mix both parts for 3 minutes straight. I made sure to stir from the bottom and carefull mix all white leftovers into the mix. Its recommanded to use a degassing chamber, which uses temporary vacuum to suck out air bubbles from the freshly mix substance. There are some DIY degassing solutions on the internet but based on experience if you use hand stiring, not a machine one, you are good to go. Just don´t stir aggressively and fast!

     I mixed way to much silicon for this, 100g would do for such a small mold. But at least I know how much next time. It made it hard to remove the orginals for the first time. But the silicon is very resilient and I found out I can bend it with full force to get them out. First test with ice was suprisingly good and I can´t wait to a bigger version for mass ice or chocolate pralines production.

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     This was a project in an area I had no prior experience and it opens me door to many both cool and practical applications. I am currently working on a rubber stop that can be mounted behind doors on else where you want to prevent impacts. I am using a 3D printed mold for this as the negative. As always, you can find many more projects on my Printables profile. See ya next week again deep inside software.