I prefer one-piece silicone cut molds in almost every situation. But this time a two-piece mold with a precise cut line was the way to go. The simplest shapes often provide the greatest challenge to the mold maker.
Skip to the good parts:
00:00 Good Morning! It's a simple object with a complex mold solution!
01:05 When to use a two piece mold instead of a cut mold.
02:40 Hard or soft, which rubber to choose?
04:18 Pouring mold registration buttons.
07:27 Building the mold box.
10:58 Applying parting agent.
11:55 Pouring a seal coat of rubber.
14:20 Pouring the first half of the mold; filling the box.
18:05 Disassembling the parting line.
18:55 Light cleanup of flashing on the first mold half.
19:48 Testing the parting agent to be sure the rubber will not stick to itself.
20:17 Making a custom sprue and funnel.
23:00 Applying the parting agent to the 1st rubber mold half.
24:50 Attaching the sprue and vent to the model and the case.
26:46 Pouring the 2nd half of the mold.
28:11 Taking the mold apart. Did it work or did we fail?