Making of

Making of the Nebra Sky Disc

The Sky Disc was made in several steps, which we would like to briefly explain to you with the help of the following illustrations:

 

The copper and the tin were smelted and then the bronze blank was cast.

By the way: The melting temperature for copper is 1985 °F, whereas tin requires only 449,42 °F.

 

After the casting of the blank, it was driven out with a hammer-like tool. This means that the blank was forged into a circular, flat shape. To avoid cracks in the bronze, it was reheated several times in between.

In contrast to the accompanying finds – which were cast in a mould – the Sky Disc was forged from a cooled bronze casting cake.

The next step was to create the so-called inlay grooves. This process – known as inlaying – is an extremely unusual technique for central Europe. With the help of a hard bronze chisel, the outlines of the gold appliqués that were to be inserted later were incised as fine lines on the disc.

Now the finely cut gold sheets could be clamped to the disc by hammering down the inlay grooves.

 

Today’s green colour is the result of the corrosion process to which the Sky Disc was exposed for several millennia. This led to the green malachite layer that covers the disc today.

We assume that the original Sky Disc was dark. Against a bronze-coloured background, the gold appliqués would barely have stood out. A black patina could be created by slowly heating and carefully polishing the disc.