Ive been wanting to try my hand at this. I have 3 questions
1.) what did you make your molds in? Like was it a cup or??
2.) how did you make separate molds for the top and bottom?
3.) is there that you put on the molds to release the cap after it has dried?
I used an empty acrylic paint tube. The top and bottoms are cut off and there is a cut going down the side. It's the perfect diameter for a key cap to minimize silicone waste.
To make a two part mold you make each half in different stages. I'll take some pics of the process later on. First I lay down a thin layer of clay. (Pictured). I make it a little wider than the diameter of the tube and I also make sure it is perfectly flat. Then gently press the key cap onto it ever so slightly. All your looking to do is make a seal with the clay, not sink the cap into it. Then I electrical tape my tube together and press it into the clay around the cap. Silicone is ready to be poured in at this point to make the first half.
For the second half, remove the cured silicone with master inside as a single unit. Do not separate. Clean off residual clay and brush/spray on your silicone mold release. Place it back in the tube in the reverse direction. Seal the tube and pour the second half of the mold.
I don't bother adding sprues before molding. I drill them in after both halves of the mold are created.
Mold release is not needed for anything but preventing silicone sticking to other silicone.
It's not as complex as I may have made it appear.
