• Review: Prometheus White Bronze Metal Clay by Laura H Elliott BA (Hons), Dip

A brilliant replacement to using silver metal clay or a clay that needs Prometheus to go back to the drawing board? 

Updated On: 21st September 2016

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Above: A final selection of pieces from the Landscape Gems collection of metal clay designs

Since starting metal clay I have loved every minute of creating sculptural work in Fine 999 Silver Metal Clay (Art Clay); however, the Prometheus Copper and Bronze clays offered affordability and the ability to go large scale (as shown below):

Above: ‘A Stitch In Time, Saves Nine’ by Laura H Elliott

As an artist who is passionate about sculpture from as long as I remember, it took a lot to entice me back into sculpture. The reason that I had not returned to clay since 2003, is due to my physical limitations and lack of access to a kiln to fire my work. When I found metal clay I was hooked, the ability to use my skill set in clay which is on a small and achievable scale.

Above: Sold – ‘Wave’ by Laura H Elliott

My first creation was in silver metal clay and was a really fast learning curve, with me realising how to use the expensive, yet beautiful, medium. I created some simple abstract landscape pendants and I was pleased; however, learning and, therefore, wasting expensive silver clay was a crazy technique. 

Above: Sold – ‘Spring Blossom’ by Laura H Elliott

I then realised that copper and bronze metal clay where on the market and offered me a very affordable alternative (see above). I purchased 100g of each and experimented, with varying results with a list of problems plaguing my efforts especially with Copper clay: cracks, splits, pitting, flaking. I found that the great technique of conditioning the clay is crucial and I used a mixture of patience, water and glycerine to minimise the cracks. I also found that creating slip from the clay and syringe clay a very useful asset, allowing you to create intricate designs, signatures and so on.

It was around September 2015 that I found out that Prometheus had released White Bronze metal clay and I was excited to try a new medium!! Plus, I had just been accepted to exhibit with Flux exhibition at The Royal College of Art, London and I thought it would add a new highlight to my work. 

This white bronze clay sounded even better as it claimed that you could mix both the bronze and the white bronze clay together, offering a new shade or highlight to my work. I bought pack after pack, mixed the clay, and fired it with the method Prometheus stated in the leaflet that came with the clay, but to no avail. It ended up a waste of money!! I found the traditional bronze was and still is as a reliable and beautiful medium and copper is even more reliable and beautiful. After wasting a great deal of money I finally fired a small piece, which I polished in the hope to reveal a beautiful colour after pickling and cleaning, but that was not the case!! It was dark grey, even a charcoal colour, which is not even slightly what the manufacturer shows in their visual examples!

So…. after a great deal of my precious time pre-exhibition and, as the old saying goes, “time is money”, I have stepped away from Prometheus White Bronze Clay. I use a fantastic kiln, I have followed the instructions and I have fired repeatedly, to no avail. I even destroyed some beautiful pieces, which was heart breaking! One is shown below:”


After a few weeks, I returned to Prometheus Copper and traditional Bronze metal clay to comeplete work for Flux, but it was a stressful time and not what creating should be about! It is meant to be therapeutic and relaxing, but the white bronze clay was not.

My recommendation is as follows:  

Go ahead and try it. Give it a go, but be guarded about your work and financial outlay and time; however, that is always something you have in the back of your mind… will it work? That is always the question and the esscence of trying new mediums. A new firing schedule could help to achieve what the manufacturers promise, which I was given by a fellow metal clay designer:

Prometheus White Bronze Firing Scedule:

This kiln firing schedule is a 2-step method


Although this is the firing schedule recommended by the manufacturer, firing the White Bronze is not as straight forward as siver clay and can be a bit tricky. 

* We advise doing a couple of test strip firings first to ensure your pieces are sintering properly. 

* If your piece is still a dark charcoal gray after firing, it has not sintered fully. 

* We also recommend only firing one or two pieces at a time and make sure they are well covered with carbon. 

* Use a steel firing container with a tight fitting lid.

* You can combine  PWB® with PBC®, PCC® and fire with the same firing schedule. Please note that at this firing schedule, shrinkage of the White Bronze Clay is 10-11%.

Firing Schedule:

Step 1: Place your dried piece on a stainless steel mesh and put it into a cold or preheated kiln at 500°C / 932°F. Fire the piece for 10 minutes. Take it out onto a fire proof surface and let it cool down.

Step 2: Put your piece in a suitable container and cover it with activated carbon. Close the lid and put it into the kiln at 770°C / 1420°F for 2 hours. When the firing is completed, either leave it to cool down in the kiln or, carefully take it out and leave it on a heat isolated surface until it is cold enough to take your piece out.

Step 3 – The Annealing Process: In order to maintain high strength and malleability, PWB® needs annealing. Heat your pieces at 565°C (1050°F) for 5 minutes and quench in water.

Here are a few of my pieces pre-firing, which where completely ruined:

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I hope this helps those who are unsure of investing in the product, at least then my time was not a total waste and this is some “food for thought”! If my oppinion changes over time, I will re-post with my ideas and some guides on firing and how to get the clay to be as visually pleasing as Prometheus claim on their packaging.

I have shown my after firing disasters below so you can see when they have been incorrectly fired and ruined. 

These pieces have cracked, broken, have bobbles of clay on them and are an ugly grey colour. They where put into the bin after photographing and used as examples for readers of my blog:


Above: Pre-firing in White Bronze

Above: After incorrect firing which has destroyed the piece

Above: The reverse after incorrect firing which has destroyed the piece
Above: ‘Ruby’ by Laura Elliott BA (Hons). This is the final piece created from traditional Prometheus Bronze Metal Clay, which was originally in White Bronze metal clay

DESIGN NUMBER 2: Watch Strap Sections

Above: At the top left you can see the watch strap sections before firing

Above: The bobbles all over each piece after incorrect firing which has destroyed the piece
Above: The bobbles all over each piece after incorrect firing which has destroyed the piece

I am going to re-try this clay, with caution, to see if it can be sucessful and I hate to give up on anything. We will see when I try it in late 2016!

We will wait and see what the future holds!!” ~ LHE

All artworks & designs displayed are © Copyright by artist Laura H Elliott BA (Hons), Dip.

View my professional gallery of works at:

View my work quick link @ http://www.lhe-art.co.uk

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2 thoughts on “• Review: Prometheus White Bronze Metal Clay by Laura H Elliott BA (Hons), Dip

  1. Did you by any chance try firing in paper towels and fiber blanket? Unorthodox I realize but it’s an old recommendation Prometheus had when bronze first come out. It can actually work which is interesting. Apparently proper sintering of these base metal clays is an balance of burning off the binder which requires oxygen. The sintering itself does better when oxygen, therefore firescale, bubbling, pick marks are also reduced resulting in better finished products.
    I just got some white bronze in and I’m excited to try it out.
    Thanks for sharing

    Liked by 1 person

    1. Hello Holky

      Thank you for your comment. I will have to try that. Do you think activated carbon might work too?
      I will try it again, but hopefully it might be okay this time. It is disheartening when beautiful designs are ruined.

      Let me know your thoughts and thank you for reading my blog.
      Laura 🙂


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