Nothing, scary, either–we’ve left that–and Halloween–behind for this year. I’ll be teaching this class tomorrow, so come join us at Two Loose Beads in Houston! This post is about my experience making a second hollow bead to take to the class, along with the bead shown above. As sometimes happens, things didn’t turn out as expected, but that doesn’t always mean that the result negates success!
Clays contain a lot of moisture that of course evaporates when meeting air, causing clay to shrink into itself and potentially stress the piece one is making. It’s definitely a consideration when building hollow forms from any clay, but the two silver clays I have used have actually presented no problems; i.e., separation of joined parts and attachments. Additionally, I have seen no drying cracks for either Art Clay silver or PMC3 in building these beads, but two days ago I was tossed a surprise after firing some silver clay hollow forms. More on that later!
Bronze, however, is a different story. It was the desired medium for this second form, for which I used a paper clay armature (in my classes we have previously built lentils and hollow hemispheres without the use of support). I was blessed with a new idea for a pendant: the first photo shows the paper clay form, and no doubt it became a sad little shabby, dirty and broken piece by the time I was done with it. The form was pure white and beautiful before it was covered in that golden clay! I forgot to take a photo of it, too. But that is history and ultimately I remain fixed on the goal, with new knowledge for success down the road. For now, the best I can offer is to share what happened when the bronze slabs, under equal conditions to application of silver clay, were applied to the paper clay form. Click on the photos for captions.
I bear no bitterness of course; it’s mostly always a matter of tweaking, one of the forgiving parts of clay work. Tests our patience, spurs growth, makes us smarter for the next time. Joy! The process for both bronze and silver was the same: handling of slabs, holes, paper clay, completely enclosed with no uneven thicknesses. But while the silver clay bead never showed even a hairline crack from shrinkage, the raw bronze clay wasted no time, and progressed rapidly enough that I attempted a hermetic seal over the piece to slow down the drying (and so I could eat supper!). It was clear that nursing this one for hours was inevitable, though, so after my meal, when the piece displayed cracking like that on the banks of a drought-plagued creekbed, I decided to stop chasing that force of nature. Next time I will dry the slab loosely draped over the form, and add the dried sides secondarily. Construction of dry parts works. I’ll have to be careful of delicate dried bronze clay–which by the way is nicely a little flexible–but that’s preferable over mopping up after dry creek cracks over how long a time only heaven knows.
Meanwhile, over the interim I started over by going back to PMC3. Such a dream clay. I have few words here, because the clay, ever my servant that aims to please, takes care of everything. And I chose another project. I can’t recall what generated this one; all I can report for now is that I wanted to take to class a new and festive hollow form preferably as a completed pair of earrings. Some photos from that process. That there is frequently something to learn is to be demonstrated again….yessirs…
I fired these fun forms Wednesday. Look below and see what happened! The cones are the same size as the mold, but PMC3 shrinks up to 15%; the paper clay did not burn out so the metal clay could not shrink. I used the same kiln program as for my small round bead, changing it for PMC3 instead of Art Clay. I didn’t anticipate it wouldn’t work; I certainly thought the armature would disintegrate. But in fact, the forms are a mite larger than the mold–since the clay added that height and thickness, but that’s just blather talk. Dear readers, tell me what I’m going to do!
Yes, readers, I agree. Refire. I had already put them in water to dissolve the material, but that was moving slowly so I drilled some holes in the paper clay and soaked them longer. I finally dug it all out after Thanksgiving festivities were packed away. But wait!–it is likely that in a second firing they may not shrink any more than this–exactly like a ring that’s been fired once around an investment plug: I have done that exact ring refiring with the result of very minimal shrinking. Stick a firing fork in this one! I’m wondering if the burnout didn’t occur because there was the big opening in the one end of the cone? Physics, anyone? Should I have stood these upright to fire them, thus almost completely closing off the bottoms? My first bead had two small holes in it, so maybe an O2-restrictive environment is necessary?…I am going to look for information on that topic.
Much to do, and I know I will be able to make my golden pendant (and my Conehead earrings). Always lessons to be learned! It feels good to have new solutions to try. I’ll post my results later, and invite all ideas and comments! HaPPy ThAnKsGiVing!
Until next time,