Herein lies the tale of my first adventures with the creation of a two-part mold. I have not yet perfected it, but the first two efforts have yielded extremely promising results. I tried to take plenty of pictures for people to follow in my footsteps if they wish or to spot and warn me of problems I face - or of easier approaches I could take.
I began by gathering my materials - Alumilite's HSIII silicone, Sculpey, a mixing cup and stirring rods, wax-paper, a section of 2-inch PVC pipe, and the object I wished to mold.
Oh, and coffee.
I selected 2" as my pipe diameter based on a dome diameter of 1.25" and the desire to leave at least .25" of space between the master and the wall of the container, for a minimum acceptable diameter of 1.75". In the end, 2" pipe was the size I had available.
To begin, I filled the bottom end of the pipe with sculpey and tapped the dome lightly in place.
Then I poured in the sculpey to cover the dome by roughly a half-inch. I ended up pouring up 4 more molds at the same time of the more conventional 1-piece type we're used to.
When the HSIII had cured, I shoved the entire assembly out with the aid of an endcap I'd bought for another project.
Then I peeled away the sculpey to expose the underside of the dome. I hadn't been careful in getting my sculpey's surface good and flat before putting the dome down, so this mold has some less-than-perfect detailing around the dome's rim.
Then I put the first side back into the PVC with the inside of the dome now facing up. I liberally applied Cast'n Craft mold-release all over the exposed surfaces so the two layers of silicone would not stick together. I then poured it full of HSIII, again allowing about a half-inch or so.
When it set, I peeled the mass out of the tube. Given the coating of mold release, this went far more smoothly than it had the first time. There's a note - spray the inside of the PVC pipe with mold release - things are easier if you do.
My headache has come back, bordering on a migraine, so I'll have to finish up the tutorial later when I can stand to focus/concentrate on stuff.
