Second part of moldmaking was getting into object casting, dealing with releases for different materials, how to make various rubber molds, from injection to zipper cut to simple glove molds, and brush molds with added colorants and polyfiber for strength. We had to do two materials of one object, a waste mold (not shown, but it’s a clay sculpture that gets a plaster mold – mine was 4 pieces – and then the clay is broken/washed out and the mold is used for another material), and 15 casts from a rubber mold of an object.My waste mold came out well, with only minor fixes and seam clean-up, even after its rushed 4-part mold process around midnight before Public Safety came to lock up. I used a funky mountainous blob shape out of clay, decided on my dividing lines and made clay walls along them, indenting some for keys to re-align the parts when pouring later on. There was even a giant undercut on one side that got its own piece and held up very well. My confidence in plaster-burlap has increased .
Next up was a rubber mold of something, cast in two materials. Mine was a pair of axe-head bike pedals I made out of wood and held together for a single brush-on mold. It worked well, I got one cast in plaster (not shown) and one in Smooth-On white plastic. I’ll need to add some texture for traction before putting them on a bike.
Last was the multiples project. Demanding only because of the amount of time it felt like it would require, I stressed and hurried the process. Originally I was going to make a fridge-magnet planter, made out of plastic packaging from a padlock. Because of its shape, I had a 4-part mold, but rushed it and so didn’t do a clean job at it. Consequently, the mold wouldn’t seal when I put it back together for pouring, and I lost about 6 out of 9 attempts, wasting my first batch of Aqua Resin I’d bought off a friend.
A mad night later I’d concocted – with that same friend – a new plan, cutting a piece of birch bark into a birch leaf shape, bulking it up with clay and casting that in alginate. I poured plaster in that and left it in a drying cabinet in the ceramics wing.
The next day I came back and shellacked it all day, pouring its rubber mold that night. The following day I returned to measure the amount of Aqua Resin mixture and accelerant needed for each cast, and got a nice minimal amount.
By the end of the day, I’d finished my 15 casts and came back one more afternoon to do minor clean-up on other things before the deadline 2 days later. Et voila! 15 birch-bark-leaves for …. whatever you want to use ‘em for. Definitely learned some lessons during this phase of class as well.