This week's assignment was to design a mould, create it, and then cast using the mould. Since I am going to need metal rocks for my final project, I thought this was a good way to make them. ("Two birds with one stone," as it were...)
First, I downloaded a free software called Sculptris from pixologic.com. This is an easy to use software that I have been wanting to try out for my 3D printing class that I teach for young children. It is basically like sculpting with a ball of clay, virtually. In order to get the hang of the software, I watched this video as an introduction.
I played around alot with the draw button, chanigng the brush stroke size and strength. It was a lot more difficult than using one's fingers on a piece of clay, but eventually I figured out a combination of things to do. The grab tool was quite effective, so I eventually started my rock all over and just used that tool (plus the smoothing tool) to create an organic looking rock.
My finished rock file can be found here as a Sculptris file. I printed the rock, but I swapped it out for a found rock. I put a nice line of hot glue around the edge of the rock, so that the liquid rubber wouldn't seep under the rock. Then I mixed the rubber. I used Oomoo 30 Tin-Cure Silicone Rubber from Smooth On to create the mould.
One of the chemicals in the bottles was very thick when I opened the box, so I tried my best to mix it up as well as I could, but it was like stirring bubble gum. The final mixture had blue and pink streaks through it and wasn't a solid purple color like the directions said it should be. I tried it anyway, and kind of glopped it onto my rock.
I was pretty sure it wouldn't work, so I was surprised when I tried to remove it a half hour later, that it was fine! The rubber peeled back nicely from the rock and sprang back into place.
Now I had to cast the rocks, and I wanted to make sure that they had metal in them for my final project. So I hot glued some washers together and tied them to a piece of thread, and I suspended them into the mould so that the washers were not touching any side of the rubber mould. This took awhile, but when I was done I was ready to mix the casting agent.
I wanted the rocks to feel heavy, so I used Amazing Casting Resin, which was "easy to use and Cures in 10 minutes!" I bought this box at Michaels, so I was skeptical of it's claims.
Surprisingly, though, this resin turned out to be "Amazing, Super, and Maravillosa,"" just as the box stated! It took just over 10 minutes for each stone to dry. When you first mix the two chemicals, they are translucent, but as the mixture hardens, it becomes opaque, so it is easy to tell when your piece has cured.
Once I had two decent rocks cast, I sanded them down a litte and then spray painted them black. I think they look great!
I did another moulding and casting project. Yay.
I designed a mould using Tinkercad and an image I found on the internet of MC Esher lizards. I wanted to mould and cast these because you definitely need more than one!
Here is my .stl file which I designed on Tinkercad.
I cut it on the Modela using Fab modules, but it took me twice to get the cut right. The first time, my cut just went around the edge of the lizard. I fixed it for the second time, though, and it cut just fine.
Once I had a decent lizard, I was ready to pour my mould. This time I used another Smooth On product, Mold Star "Platinum Silicon Rubber."
I mixed equal parts and carefully oured it into the wax cut out of my lizard. Then, to get the bubbles out, I tapped it vigorously on the bottom of the wax block repeatedly until most of the bubbles floated to the surface.
After about 40 minutes, I carefully peeled the mould out of the wax.
Then I used the same solution I had used to make my rocks. I mixed up a tiny bit, and carefully poured it into my mould. It mixed clear and when it began to set, it began to turn white.
After about 10 minutes, the casting was ready to come out of the mould, and it looked great. I made three of them, so I could start the Mc Esher lizard puzzle. When I have more time, I'll make 100.
