Here is a quick first look at a silicon molding project for making hot end covers. The goal for me was three-fold.
1) Testing my ability to quickly design a mold for silicon
2) Create a hot end cover that would keep in heat and provide protection against finger burns
3) Testing the heat resistance and durability of common weather sealant silicon found in the local home improvement store
The hot end heater block used for this pattern is the one used on the current Gigabot (GB3). Using Solidworks I designed a bounding box around the hot end large enough to give 0.1" wall thickness to the silicon. The second part of the mold is a combination core and top lid for the mold cavity. When the core and box are assembled there is empty space inside for the silicon.
100% Silicon mixed 5:1 with corn starch (used to decrease drying time) was injected into the mold using a syringe.
The silicon was left to cure for one hour and the mold was disassembled. I was happy to find the mold fit the GB3 hot end heater block snugly and is now ready for heat testing.