10 Jul 2012

Bringing copper clay to life

Firstly, I must apologise for the delay since my last post, but between health issues, our annual ‘summer’ holiday (I use the word advisedly, it didn’t feel much like summer in the storms) and being kept busy with some lovely custom orders, time has simply got away from me.

As I promised that I’d post this subject some time ago and I’ve already prepared the photographs, I may as well continue and complete the post, even though some considerable time has passed since I said I’d be doing so.

I’m going to show the many stages it takes to make a jewellery set like this from copper clay.

As previously posted, I’ve really been enjoying working with copper clay, a somewhat new adventure for me. I resisted for some time, until I felt I’d mastered sufficient skills with actual solid metal before taking myself off on a tangent. It’s an amazing medium, it allows you to achieve results that would be either very difficult, time consuming or even impossible with solid metal forms. I read an article by an experienced jeweller that said she used PMC for things that she simply couldn’t do by other means – as a supplement to metal, not instead of. So that has been my thinking with it thus far. To try things that I couldn’t otherwise accomplish. Hark at me, like I’m an expert. Far from it, I’m learning at a very steep rate and still have a long way to go.

Whilst it’s amazingly good fun to work with and you can do really interesting things with it (and I’ve only scratched the surface so far) – I don’t feel it’s a short cut to quick or easy results either. It still takes a lot of work to get good results. I suspect in my case some of that is related to the fact that I’m torch firing and not using a kiln – it takes longer to fire the piece in that each one has to be done individually and I suspect that the firescale on the copper I’m using is possibly deeper – and more time-consuming to remove too.

I thought I’d show some work-in-progress photographs of the various stages that a piece has to go through, not as a tutorial in any way (I’m simply not qualified yet to try and impart information on this subject), but purely as an insight as to how much work a particular finished piece represents. The particular design of the pieces indicated is a rather simple technique, pieces that incorporate sculpting and assembly of components can take much longer.

Most of the photographs are of a particular earring and pendant set, although some of them were taken retrospectively with another piece as I simply decided later that I’d missed some stages worth including.

The clay is rolled out to the desired thickness on a non-stick sheet, in this case, using some sheets of plastic as my spacers.

I imprinted the sheet of clay with my chosen texture – in this case, a spiral I formed with a piece of wire.

The shapes are then cut out of the sheet and shaped and formed, as desired, whilst still moist and pliable. They then need some time to dry enough for further handling. I choose to do some of the further work before the pieces dry to the stage of becoming brittle. At this stage it is certainly more clay and less metal (despite the rather incongruous sensation of being cold and metallic to the touch) and I liken it to dry pasta – firm and robust enough to handle, but you could just break it with your fingers if you chose, so it does need some care. I like to drill my holes and refine the shape a little whilst it’s dry to the touch, but not dry enough to fire – it simply seems more brittle to me by the time it reaches that stage.

The left hand earring piece as I formed it initially from the moist clay and the right hand one is after some filing, rounding of corners and refining the shape and surface – as you smooth it, it does take on a more metallic appearance.

At this stage, I leave them on wire mesh to dry really thoroughly for at least a couple of days. I’ve had some pieces crack or pop during firing and the manufacturers advise me this is the rapid vapourising of any tiny water molecules remaining within the clay as I bring it to the flame to fire it. I’m not convinced that moisture is entirely to blame for all my cracks (and I’ve made some modifications in my workflow to address the issue), but I think it must certainly have been in the piece that popped loudly and broke away surface pieces as soon as it got hot.

I fire each piece individually with the torch, in accordance with the recommendations for the particular product I’m using. I can manage either a single large piece or a couple of smaller ones in each firing. I work in reduced light so that I can monitor the colour of the metal and the flame.

After firing and quenching, my lovely smooth piece of clay looks pretty terrible – the firescale on the surface will need removing – and this is perhaps the most tedious stage of the process, although some trial and error has established a pretty good routine for me to get it clean again with minimal elbow grease. First I pickle and then tumble the pieces extensively to bring out the shine of the metal now revealed after burning off the organic binders.
Of course, the metal clay pieces are only components and I also need to make the accompanying metal parts too – in this case, I decided to go for some fancy feature earwires with a co-ordinating decorative spiral. I also make all my own jump rings and clasps for finished pieces.

The earrings are as such now complete and I’ve antiqued them to bring out the lovely aged warmth of time-worn copper, which is my own personal preferred finish for copper. I’m next going to add some colour to this particular set and after some earlier trial and error, had decided that antiquing first and then applying the colour gave the most pleasing end result. Before colouring, I removed the copper clay charms from the earwires to protect them.

I’d originally had it in mind to combine the copper clay pieces with enamels, but whilst researching types and materials, came across the US made product Gilders Paste, which sounded even better for what I had in mind. It’s a solid opaque and intensely coloured wax type substance that comes in little tins and looks for all the world like old-fashioned shoe polish. It can be used and applied just about any way you can think of – you can do anything from rubbing it on with your finger to airbrushing it on as a wash mixed with a solvent. I decided that a short cut-down and very inexpensive paintbrush allowed me to stipple it well into the recessed pattern areas, giving good coverage.

It’s specifically for colouring metal, but can be used on many other suitable surfaces too. I’ve found that it seems to work very well on the less metallic and shiny parts of the clay that were impressed and therefore not as subsequently highly burnished smooth. Still maintaining some of the porosity of the original clay texture gave it a good key to adhere to. I think for a good covering on the metal surface, it would need roughening to give it a better key and would lose some of the metallic sheen and therefore may not be quite as attractive for the effect I was after. On solid metals, I found that it scratched off too easily, but it adheres well to the rougher texture of unpolished clay areas. Solid copper would need a texture for key to work reliably – but I have some ideas for that too.

Once allowed to dry for a number of hours, the piece can be rubbed clean and finally polished – the Gilders Paste is robust once dry and should last well in wear. On these pieces, I stippled both a verdigris turquoise with a darker metallic green to give the appearance of patina but I didn’t want a solid single flat colour. The photo below was taken between wiping off the excess from the surface before fully dry and the final buffing and cleaning.

Some finished copper clay pieces using Gilders Paste for colour:

And finally . . .

As I’ve been typing this, with the TV on in my office, the weather man declared that some places in Britain today (the 10th of July, may I remind you) were actually colder than they were on Christmas Day! So you can see why I had some reservations about declaring our most recent holiday to be our summer one!