Dichroic Glass - So What?

Dichroic glass has been around for several years now. You may have come across it in your travels around the web especially if you've been looking for jewellery. Just a few years ago you were only likely to find dichroic glass jewellery in gallery shops. Why? Well creating dichroic jewellery items is not a straightforward or inexpensive process.

Dichroic glass - what is it?

The 'dichroic ' part of the description is a space age coating that was developed by NASA for their space mirrors. The coating contains metallic oxides in precious metals and is applied to the glass surface in a vacuum process to a depth of no more than 3microns thick (which isn't very thick at all).

Some bright spark - I have no idea who - thought the dichroic coating would make a fabulous addition to the decorative art of fused glass. Why do you have to fuse dichroic glass? Well the coating in an unfused state can be scratched off. By fusing (controlled melting) the glass in a kiln to temperatures above 750 deg C or there abouts the coating becomes a permanent part of the glass. And so dichroic glass jewellery was invented.

The pioneers of this glass work had to play around with little bits of artglass that cost enormous amounts of money for not very big bits. Even today a 2cm x 2cm piece of dichroic glass can cost the best part of £10 depending on the colours and patterns. Then the jewellery item is assembled for firing. This means that a piece of dichroic glass (on black or clear) is sometimes capped with a clear piece or even a third layer can be added to build the piece. The glass pieces are cut to shape, glued to make the 'sandwich' stay together through the early stages of fusing and placed in a kiln and heated in a controlled temperature cycle to make the layers fuse together. Once they have fused the glass piece needs to be carefully cooled so the piece is stable.

If all has gone well - the piece (if a freeform ) is ready to make into jewellery. However, for more refined pieces it might be necessary to reshape and pop back into the kiln to fire polish (get rid of the hazy surface created by grinding the glass into a more refined shape) it. Some pieces are fired in a kiln 3 or 4 times.

Jewellery construction: What is fabulous about dichroic glass is the freedom to experiment with different construction methods. The simplest is gluing (also called cold fusion) using 2 part epoxy glues. These are very powerful glues and will hold fast in most conditions. Another simple method is wirewrapping. I say simple, it is technically more demanding and difficult to make it secure and attractive. There are two main routes to choose - grinding a channel (groove) around the glass cabachon and fitting a wire around it and using multiple strands of wire and bundling to trap the cabachon securely. Another method of trapping using seedbeads to form a bezel around the cab and a related method glues the cab to a backing material and then weaves a surround. The final method is to bezel set the cabachon as if it were a gemstone using sterling silver, copper or gold.

What else is special about it? For me it is the intensity of the colours and the changeable nature of the glass (particularly the clear capped) that I love. It makes it very alluring to wear with different colours but a devil to photograph well.

Today dichroic glass jewellery is still not cheap to produce. The raw materials have come down in price a bit as production methods have improved but you still need a kiln and it still takes time. That said you can get a freeform pendant on a silverplated bail for a fiver (£). It is a fun, fantastically colourful material to work with.

So ends my description of dichroic glass - next time you see a humble little glass pendant with the label 'dichroic' please remember it is more than just glass.