Prometheus Bronze Clay

How to Fire Bronze Metal Clay

Prometheus Bronze ClayExperimenting with metal clay jewellery designs? Ever thought about trying bronze? If you haven’t already tried out Prometheus Bronze clay, this metal clay is simple to work with and will give you a professional result in no time at all.

To help you get the finish you’re looking for, use our guide on how to fire bronze metal clay. With some straightforward Prometheus bronze clay firing instructions and a full breakdown of the tools and supplies you’ll need you’ll soon be able to produce unique bronze metal clay jewellery pieces that your customers will love.

How to fire bronze clay

Prepping your Prometheus bronze clay for firing

Before you start the firing process, you’ll need to make sure your bronze metal clay design is completely dry. During the design and sculpting stage, your clay will be wet and more easily sculpted, but once you’re happy with your design you should always leave it to dry out completely.

Can you speed this drying process up?

With smaller pieces you may want to carefully try drying your bronze metal clay with a hairdryer. Alternatively, you could place it on top of your kiln (if you have one) or a hot plate to dry out entirely. This means that you won’t have to wait as long when it comes to firing your bronze metal clay.

You can test your metal clay to make sure that it is completely dry before firing. Simply take a cold mirror and place your clay on it. Leave it on the mirror for just a few seconds. Is there any condensation left behind? If there is, your bronze metal clay is not completely dry yet. Leave it for a little longer and test it again to make sure it’s completely dry.

Tools for bronze clay firing:

  • Hand torch or Kiln
  • Bronze clay
  • Soldering block
  • Tweezers
  • Spatula
  • Stainless steel woven mesh
  • Brass bristle brush
  • Pickling solution

Kiln firing bronze metal clay

Kiln Firing Method: Prometheus Bronze Clay
Firing time 30 minutes
Temperature 820ºC

How to fire bronze metal clay using a kiln:

Prometheus Clay Kiln

  1. Set your kiln to 820ºC and wait for it to reach temperature.
  2. Place your bronze clay jewellery piece onto your stainless steel woven mesh.
  3. Place the mesh onto a spatula with a wooden handle and carefully place in the centre of your kiln.
  4. Once the door is closed, make sure the temperature goes back up to 820ºC.
  5. Once the kiln reaches the right temperature again, set the timer for 30 minutes.
  6. Once fired, take the bronze clay jewellery piece out of the kiln and place it on a heatproof surface while it cools. A soldering block is ideal.
  7. Now prepare some pickling solution.
  8. Place your jewellery piece into the pickle and wait for the black oxides to start coming away.
  9. Remove from the pickle and rinse.
  10. Continue to remove the oxidisation using a brass bristle brush.

Torch firing bronze metal clay

Torch Firing Method: Prometheus Bronze Clay

Minimum firing time (once binder has burnt off) 7 minutes
Target colour Red

Here’s how to fire bronze metal clay using a hand torch:

Jewellers Hand Torch

  1. Place your bronze clay jewellery design onto your stainless steel wire mesh and sit this on top of your soldering block. This will protect your work surface.
  2. Light your hand torch and start heating the bronze metal clay using a circular motion so that all areas of your design are being heated equally.
  3. Your clay will then catch fire. This is completely normal! It means that the organic binders in the clay are beginning to burn away leaving you with the bronze metal.
  4. Continue to heat the clay until the binder burns away, leaving you with a piece of bronze metal that is glowing red.
  5. Now start a timer. Prometheus bronze clay has a minimum firing time of 7 minutes during which the sintering process takes place.

What is sintering?

What is sintered bronze? Sintering happens during the firing process and is when the tiny bronze particles in your metal clay get so hot that they start to make a stronger bond with each other. Before sintering happens, the metal particles are not connected and make the metal weaker. As the sintering process continues, the metal particles merge and the metal becomes stronger. That’s why it’s important to ensure you use the recommended time for firing your bronze metal clay, making it fully sintered and as strong as it can be.

  1. Continue heating the jewellery piece for the allotted time making sure that you keep the flame moving for a consistent firing process.
  2. Is your 7 minutes up? Turn off your flame and quench the bronze in some water using tweezers.
  3. Now prepare some pickling solution ready to remove the oxides that have collected on the surface of your bronze design.
  4. Remove from the pickle and rinse.
  5. Brush your bronze metal clay design using your brass bristle brush to remove any oxides that are still clinging to your design.

5 bronze clay firing problems to avoid

  • Think about shrinkage. Remember Prometheus bronze clay shrinks about 6-10%, so make sure the jewellery piece you’re working on has been measured to account for the shrinkage that takes place during firing.
  • Proceed with caution when drying. Before the bronze clay firing process, you’ll work on the design while it’s still wet then leave to dry completely. With larger pieces, don’t try to speed this process up with a hairdryer as drying it out too quick could leave it prone to cracks and breakage.
  • Firing larger pieces? Firing bronze metal clay can be done in a kiln or with a hand torch. But remember that pieces of bronze metal clay that are larger than a 50 pence piece are much easier to fire in a kiln. And it’s a more accurate way of ensuring that your bronze metal clay jewellery has been fully sintered too!
  • Keep your eyes peel for that cherry red glow. Throughout the bronze clay firing process, watch out for the cherry red colour that means sintering is taking place. If the piece is glowing orange, that usually means that the bronze clay is a little too hot so pull your flame away slightly to leave you with a glowing, cherry red colour instead.
  • Stick to the firing schedule. It’s important to stick to the bronze clay firing schedule of 7 minutes. If you don’t it’s likely that the metal will not be fully sintered and the piece may be weakened.

With a better idea of how to fire bronze metal clay, you’ll be able to experiment further with your metal clay designs and create unique jewellery pieces for your customers. Don’t forget to pick up bronze clay supplies before you start, and if you’re new to working with metal clay, check out our precious metal clay kits that include all the tools and supplies you’ll need to get started.

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