Molds and Winter Progress.

Winters in Wisconsin are not easy to get through. And this year was no exception. The polar vortex gave us all a case of the Winter blues. Although I didn't completely give up on working on my project, it certainly did slow things down. Documenting my progress was hit even harder. So for the next several blog posts, I hope to give accounts of what I managed to do over the past five months along with any experimenting currently in process. 

During this time, I did manage to get a hold of some UltraCal 30, which has allowed me to mold the Jester maquette that I have shown in a previous post. UltraCal 30 is basically a concrete/plaster mix that is common in special effects makeup production and stop-mo animation. Before receiving my supply, I had experimented on making my own UltraCal-like mix. Yet, I have come to the conclusion that its worth it to just get the real deal.

To prevent damaging my camera, I did not take any pictures until everything had set. The pictures you see below are the end result of molding. Creating the mold itself takes a little bit of practice, but is simple enough once you get a hang of it. First off, you set the oil clay maquette in a bed of pottery clay or similar compound so only half of the model is exposed. I use WED clay which is a water based clay with added glycerin to prevent it from drying too quickly. Once the maquette is embedded, its sprayed down with some acrylic coating and its ready for molding.

Then, I brushed on a few coats of UltraCal slurry to the clay bed and model. Its important that the slurry is thin enough to get into all the details of the sculpture and to let air bubble escape. This will prevent any imperfections on future castings. After those few coats, I soaked some burlap strips in more UltraCal slurry and placed them on top of the clay bed/maquette. This step strengthens the mold once its cured. Last, I added less water to some more UltraCal creating a mixture that has a thick consistency similar to clay. This allowed me to work the UltraCal into its final shape.

After the first half of the mold is made, I basically did the same thing on the other side. The only exceptions here is that a mold release needs to used (I used petroleum jelly) and the clay bed is replaced by the first half of the mold. Check out the photos to see how it turned out.

Molding set up with tools

Cured mold

Mold halves after curing

 If you want more info on making UltraCal molds, there are plenty of resources and videos out there with a more information.