PDF Print

Experiments by Chris Pate

Sample B 20.5gms not refrigerated

‘Empty Nest Ring’

Empty Nest RingSample B was the first clay received. Upon opening, the clay was much harder to the touch than PMC 3, seemed dry and cracked when pinched between fingers. The copper was clearly visible in streaks throughout the clay. The clay softened considerably on handling and warming slightly under a desk lamp. No water was necessary – although on first inspection I was tempted to rehydrate straight away.

 

Working Properties:

After softening the clay by manipulation the rolling process produced a stickier clay that picked up air pockets when rolling thinly to 1 card. There is a definite ‘copper’ odour. It holds its shape very well and does not distort. This was evident when cutting squares from a template with a pin tool which would normally distort when using PMC3. After a few rollings the copper streaks mixed into the clay and were not longer visible. Slip was made by adding pure water to the clay but it took a while to mix to a smooth consistency.

 

On rolling canes of clay of varying thickness and tapers, the clay rolled beautifully with no signs of cracking or sticking. It held its shape really well.

 

After 25 minutes of handling the remaining clay started to get very dry and break up and needed to be rehydrated with pure water. This was done by rolling the clay through two sheets of plastic as it was difficult to mix the water in by hand.

 

Handling on Drying:

When dry, the clay is quite yellow in colour. It sands and carves well.

 

Firing:

The piece was fired in a Paragon SC3 on an open shelf at 538C. The second firing was in a steel dish with lid with coconut shell carbon. I measured 1cm layer of the carbon at the base placed the ring in the centre of the container and covered it with 1 cm layer on top. The second firing was for 1Empty Nest Ring closeup hour at 821C. After firing the ring was a steel grey colour and had shrunk from a ring size of Y to a T.

 

Soldering:

The feather inside the ring was soldered onto a sterling silver peg using hard solder. Even though the ring looked clean and had been brushed with a glass brush the solder would not flow on the first attempt. After 5 mins in safety pickle the ring turned white and had no trace of oxidisation. The solder flowed but dissipated into the metal. After burnishing the area the solder was successful, but in some areas of the ring two small areas ‘bubbled’ due to overheating. These areas were carefully filed down and sanded. I would recommend careful heating when soldering and maybe use of a medium solder.

 

Strength:

The flexural strength of the finished ring was impressive. The ‘egg’ shell in parts is less than 1 card thick. The feather was also rolled to 1 card thickness. Samples of squares previously fired of 1 card , 2 card and 3 card thickness were also extremely strong and resisted bending with pliers, although persistent bending will ultimately result in the metal breaking. Flexural strength of the fired canes of silver was disappointing: they broke on the first attempt of bending.

 

Sample A 19.8 gms not refrigerated


‘Lichen Brooch’

Lichen BroochSample A was much more like PMC 3 on handling. A much softer consistency with no apparent ‘copper’ odour. A darker grey colour to PMC3.

 

Working Properties:

Rolled better than Sample B with less air bubbles appearing in the very thin rolled sample of 1 card. When cutting square samples with template and pin tool the clay didn’t hold its shape as well as Sample B and dragged with the pin tool, much as PMC3 would. Canes of clay rolled less successfully due to the softer nature of the clay but no signs of cracking. I worked with the clay over two days and didn’t need to rehydrate it. Slip was made by adding pure water to the clay which worked very well.

 

Handling on Drying:

Sample A remained more flexible on drying than Sample B. It remained a grey colour on drying.

 

Firing:

Sample A was fired using the same firing schedule as Sample B: Namely; open firing on kiln shelf for 30 minutes at 538C then 1 hour at 821C in a steel container with 1cm of coconut shell carbon below and covering the piece.

The brooch shrunk by approximately 20%Lichen Brooch closeup

 

Soldering:

The piece was removed from the carbon when very hot, resulting in thick oxidisation which was only removed by safety pickle solution. The brooch mechanism was soldered using hard solder and the areas to be soldered were burnished prior to soldering. No problems were encountered.

 

Strength:

Again, strength of the finished piece was impressive. The main body of the brooch was rolled to 3 cards thick – which would not be strong enough using fine silver clay. The lichen running through the brooch were made very fine to 1 card thickness and less, again not a design I would have attempted with fine silver clay.

 

Visit Chris Pate's website here

 

Add comment


Security code
Refresh