Friday, 4 January 2013

A Ring For Jackie

Here is my first blog of 2013.  I was kind of busy at the end of 2012.  I had a request to make a ring so I set about it just before Christmas.  The first thing to do was to size it correctly so I measured Jackie's finger and determined he was a size G.  That was the easy part.  I was making the ring from metal clay, which shrinks by 8-9% when it is fired in a kiln so the ring has to be made bigger to allow for shrinkage.  I keep a log of everything I make so that I can learn from experience.  As you can see from my calculations below, a size K was about the perfect size to shrink to a G.

And here is the 'before' photo.  This is the piece of silver clay that I used to make the ring.  it doesn't look like much does it?  It looks more like a piece of chewing gum than anything related to silver but this will be transformed into a Fine Silver (99.9% silver) ring.

First the clay has to be kneaded and softened, taking care not to dry it out in the process.  Even the heat from your hands can be enough to dry it out so it's usually kneaded inside a piece of cling film.  Once it was softened it was time to shape it.  For a textured ring, I would roll it out with a tiny plastic roller and use a texture mat to give it a pattern.  This time I wanted a smooth ring with a groove so I decided to use a mould.  I used plastic moulding material that is softened by hot water and a bamboo knitting needle to create a rounded ring mould then let it cool down to harden.

When the mould had hardened I removed the knitting needle then coated the surface lightly with olive oil to prevent the clay from sticking.  I rolled the clay into a snake shape and pressed it firmly into the mould.  After a couple of minutes, I carefully prised it out of the mould and laid it carefully on my cutting tile where I used a very sharp blade to carefully cut off any excess clay.  Next, I wrapped a ring paper around my ring mandrel and marked it where it was size K.  The next step is the tricky one.  This is where I had to drape my tiny clay snake round the ring paper and carefully turn the mandrel until the two ends overlapped then cut through the two layers where I wanted the ends of the ring to join.  I got there in the end and carefully removed the ring, still on the paper, so that it could dry.

Next is the time consuming part - waiting for it to dry then sanding and shaping it, inspecting for dents, cracks, etc. and fixing them, waiting for it to dry again and then repeating the process until it looks the way it should.  The clay is very delicate in this state so great care has to be taken not to break it or it's back to the drawing board.  After a few days of this routine it was almost ready to fire in the kiln but there was one more thing I needed to do.  The ring was supposed to have a groove all the way round so I carefully marked the location of the groove with a pencil.  I used a very fine, sharp sculpting tool to start off the groove then made it wider and deeper with a diamond file.  I fetched my kiln, set it up put the ring on a piece of firing blanket on the shelf and switched it on.  Silver clay needs to be fired at a minimum temperature of 650 degrees centigrade for 30 minutes so I'd to wait just over 20 minutes for the kiln to reach temperature then start timing it.  Here is the 'cooked' ring.

Yes, I know.  It doesn't look a whole lot different from the uncooked version you saw a couple of paragraphs ago.  To begin the transformation it needs to be brushed first with a brass wire brush.  This results in a matt / satin silver finish.  I gave the inside of the ring a gentle rub with some very fine sandpaper then checked it with the ring guage.  Size G  - perfect!  I started to polish it inside and out using a metal burnisher to bring it to a glossy shine and here is the finished article: