This week-end was about creating a plaster mold out of the "frankein-sculpt" I ended up doing. The hobby community seems to have settled on "Ultracal" as being the ultimate plaster for mold-making, but I had to settle to a locally available, fast setting, gypsum-plaster.
The pro's are also using a so-called "Wed-clay" in the process (see tutorial here from stopmotionmagazine), but here again, I had to settle for some locally available natural water based clay.
Well, in the ambient 35 degree Celsius where I am living, both the clay and the plaster seemed to be drying faster than I wanted. The natural clay was rather messy to deal with, and I had trouble to level it to the divide line of my puppet. As a result I created a lot of undesirable undercuts : whereby the puppet ended up being sunken a little to much in one of the half mold, making it impossible to release without breaking.
Oh, and I also forgot to create "keys" (holes on one side, bumps on the other) to facilitate the placement of the two halves. The plaster turn out to be very soft... and I don't think this mold will resist more than one foam-latex baking.
Well, the result is very amateurish but I think it should be good enough to mess with the foam latex curing part... which seems to be the hardest craft to master in this type puppet making. I will most likely end up with a shapeless blob but I am picking up some ideas to do better on the second try :
1 - Will sculpt the master shape in Supersculpey, instead of air drying clay, then bake it to harden, and will send the shape to pistol lacquer painting (at a motorcycle repair shop), to get the smoothest surface possible
2 - Will use Kid grade synthetic clay (comes almost cheaper than natural one where I leave) in the mold making process, instead of trying with natural clay. I will just warm it a little in a rice cooker to make it very soft. Kid clay worked very well when I made silicon molding for the corners (see earlier post). It will be more forgiving for puppet molding as well... just need lots of it.
3 - I need to settle for a plaster than does not dry so quickly... and maybe ask the plaster shop if there is a way to mix it with more gypsum powder to improve its hardness.