Crackle Enamel

Crackle Enamel

Yesterday was a crackle day.

If you are wondering exactly what that is, its making some crackle enamel pieces day, these pieces are destined to become earrings.

I really love crackle enamel. Its all about transparent enamels with a touch of opaque and long firing time. The results are always unpredictable and often very beautiful.

This time I took some inspiration from another enamelist Grace Wolf, who kindly shares some of her beautiful crackle recipes on Facebook. I don’t necessarily have all the colours she uses which of course changes the finished product, but I'm very happy with these results.

Crackle has real depth and because of its transparent nature when you look into it you can see all its intricate detail, its reactions to heat and the various melting temperatures of the different enamel colours.

My procedure for these pieces was as follows;

I cut and prepared the blanks with counter enamel and fired them.

These went in a warm pickle-pot for around 10 minutes to remove fire-scale, then they were rinsed in clean water and dried. (I use a Citric acid pickle, the recipe is easily found on the net)

Because they were to have transparent enamel over the raw copper, I gave them a once over with an abrasive wheel in my flex-shaft to remove the last of any fire scale left on the surface.

The first enamel top coat on these was a reasonable cover coat of Thompsons Opal White for sparkle, then they were kiln fired.

Once cooled, I added the base colour coat, yesterdays had 3 or 4 layers in various thicknesses of transparent colours added, the last being Thompsons 2008 Clear crackle, then kiln fired them.

The final coat on these was more of the same transparents, finishing with an opaque top coat. 

For these pieces the opaque top coat was placed in particular areas. 

The opaque top coat is flexible, it can be placed in a particular area of the piece or it can cover the piece totally, it can also be a mix of opaques, as was applied to the blue and orange piece which I added both red towards the top and orange towards the bottom, or just a single complimentary colour or any colour or combination of colours you choose, it just needs to be opaque.

The opaque coat can also be of varying thickness, anything from a light sprinkle to full cover, the thicker the coat the more sgraffito is needed to obtain the crackle effect. The pink piece had just a light sprinkle of black added where as the blue and orange piece was a heavier coat.

Once I applied the opaque powdered glass layer it was time for sgraffito. Sgraffito is an Italian term for scratching through a top layer to reveal parts of the layer underneath. This needs care as it is quite easy to remove too much of the top layer or mix it up too much especially if you have used more than one opaque colour. You can sgraffito a pattern into the top layer or keep it random. I used both methods on these pieces. The pink and blues were random and the other 2 were a pattern.

Long firing, usually a layer of enamel powder takes more or less 1 minute to fire depending on the metal type, the temperature of the kiln and the composition and thickness of the enamel layer, for crackle these were fired for 3 - 3.5 minutes plus to get the movement I wanted.

Some of the enamel may drip or run over the edges and accumulate on the sides or the backs of the pieces, this happened with these. To tidy them up and to remove the fire sale on the edges, I ran my flex-shaft around the sides and over any sharp bits with a diamond bit, and then hand finished edges with a file. They are now ready for assembly.

The colours used on the blue piece were Thompsons

T Water Blue

T Sea Green

T Crackle Clear

T Water blue

O Sapphire Blue

O Aquamarine Green