What is precious metal clay?
Precious metal clay, also known as PMC, is a malleable material made of either pure silver or 24K gold that has been revolutionary in several creative industries.
The development of this medium has allowed creators everywhere to explore working with metals in a simpler way than other traditional methods. Detailed and precise work is achievable using this material that has unique properties and will adapt so that artists bring their designs into reality.
PMC Composition
To understand how PMC works it is important to describe its composition. PMC is made from 3 essential elements: a precious metal powder, a binding agent, and water. These ingredients form the paste that will eventually become firm after molding and firing in a kiln.
A key aspect of PMC is that the binder used to form the substance will melt away during the firing process, making the volume decrease after all the steps are completed. Because of the heat, water will also go away through evaporation. It is necessary to anticipate this shrinkage when designing pieces so that your resulting piece is the desired size.
Both the silver and gold versions of the product can be combined with each other or even other molding materials to create unique pieces. You don’t need expensive equipment or tools to work with PMC, making it accessible even for true beginners.
It is possible to make changes to your PMC design during whichever stage of the manufacturing process, allowing for flexibility when creating. The paste-like qualities of it offer the possibility of making designs that are as simple or intricate as preferred, and you can reshape your piece as many times as possible before committing to a specific design.
Different types of PMC
There are several different variations of the material, each with specific properties that might aid in certain designs. The first one would be Standard PMC, which contains a 30% binder in it. This means that after firing, pieces made from this version of PMC will shrink to around 70% of their original size. Standard silver PMC is fired at 1650F for two hours, while gold is fired at 1830F for two hours.
Some benefits of using this material versus conventional fine silver and 24k gold is that PMC items are stronger and more porous, which means the results are much lighter than when using conventional metal. If you’re planning on designing large wearable pieces, PMC might be a very good option so that weight isn’t an issue.
Another variety is PMC+, which comes in silver. includes less binder (12%) in its composition, therefore reducing shrinkage. It can also be fired at lower temperatures and the firing time required can go from 10 minutes up to two hours. When fired for two hours at 1650F it becomes almost as strong as sterling silver, and if fired at a lower temperature of 1470F makes it possible to embed sterling silver findings, such as earring posts, before firing.
Finally, there is PMC 3. This variety is slightly denser than the other two, resulting in stronger pieces. It has the same shrinkage rate as PMC+ and it can also be fired for as little as 10 minutes, or for as long as two hours.
Precious metal clay: starter kit
One of the best things about precious metal clay is that artists and makers do not need traditional metalworking skills such as soldering or forging to produce their designs. It is also not necessary to have a specialized workshop; a small workbench or table will do. It is possible to roll, shape, mold, glue, stamp, and extrude PMC with simple tools and equipment.
A few of the most common tools to work with PMC are molds and texture sheets. They are usually made from polymers, and they come in endless shapes and sizes. These will allow you to imprint shapes and patterns, and to build volumes that are replicable. You can also use small rolling pins and regular crafting knives to aid you while manipulating this material. There are also sculpting tools from other disciplines like ceramics that could be used for finer details.
After molding comes firing, a step that requires you to follow appropriate safety measures. Wear safety glasses and kiln gloves when handling hot materials. Keep in mind that after firing, there are several more steps to achieve a finished piece.
You might need to do some sanding and polishing to your solid metal pieces so that they can look their absolute best. In this case, sanding paper of several different grits is recommended. Polishing can be done with an electric rotary tool or a buffing cloth and any metal polishing chemical. A steel anvil and texture hammers might also be helpful when trying to reshape and finish a piece.
Best kiln for precious metal clay
Metal clay can be fired by several different methods. The three most common firing methods are electric kilns, stovetop, or torch. Using a kiln that is specifically designed for the firing process is the simplest way to complete this step, so we will focus on this technique.
Kilns designed for metal clay are programmable and easy to use. Choosing the right kiln for your projects will always make a difference when bringing your designs to life. The main factors to consider when selecting a kiln for your PMC projects are kiln size, temperature maximums, interior materials, loading style, technical features, and accessories.
Ideal size for your kiln
The size of your kiln needs to respond to the type of projects you intend on firing. If you’re planning to do larger pieces, maybe even use it for firing other materials, a larger kiln is recommended. This is also recommended if you intend to produce pieces in large quantities continually. If your plan is specific to disciplines like jewelry or bead making, or if you’re a novice in the field, you might want to start off with a smaller version.
How to choose by temperature?
If your kiln has a maximum firing temperature of 2000℉ and it is constantly being fired near this temperature, the heating elements in the kiln will burn out sooner. A kiln´s power is reduced over time, so make sure to overestimate the temperature of your projects by 200-300 degrees Fahrenheit when choosing the correct kiln for your practice.
PMC Kilns interiors
Usually, a metal firing kiln will come with two types of interiors: brick or ceramic fiber. The former takes longer to heat but it can withstand higher temperatures, while the latter heats up more quickly, decreasing firing times. Brick interior kilns need to be cleaned more regularly because their heating elements are exposed, while ceramic fiber kilns need to have the interior completely replaced if one of their internalized heating elements goes out.
JPSKilns offers brick interior models that withstand higher firing temperatures, allowing the user to create their pieces under more varied circumstances according to their specific needs. Having a brick interior kiln will assure insulation that makes the temperature stable, while having exposed heating elements allows for easy replacement and maintenance of the kiln in question.
PMC is easily fired in these models, but you may also explore other mediums such as copper and bronze. Overall, these are sturdy and reliable kilns that can work under different settings, so creators may work on projects according to their own vision instead of being limited by their tools.
PMC Clay Kiln Loading Styles
In terms of loading styles, there are usually 2 types: front-loading and top-loading. While it is much more convenient to move things in and out of front-loading kilns, the cost of this is higher. Also, placing and replacing their interior shelves is much easier. This type of kiln is recommended for creators who will need to quickly extract pieces (usually enameled ones) at high temperatures.
Top-loading kilns may need the assistance of special lifting tools to remove pieces from them, but they come at a much lower cost.
Other aspects to consider
The technical features to consider while shopping for a kiln include the type of controller and if it includes a viewing window. A manual controller requires you to be in control of the temperature changes, while a digital one regulates the temperature and deactivates the kiln when needed. Viewing windows or viewports are recommended if you want to keep an eye on your projects while they’re going through the firing process.
Which are the best supplies and accessories for your kiln?
If you are looking to spruce up your kiln with some accessories, you may want to consider the following options:
- Kiln Shelves:
These exist in several different materials, the most common being ceramic fiberboard, ceramic board, soldering surface, and firebrick.
The different material dictates their lifespan: a fiberboard will give you a couple of dozen firings before breaking down, but a ceramic board shelf can last you for years. Soldering surface shelves also last a long time but require you to let the kiln cool before removing them to avoid thermal shock breakage.
- Supporting elements:
Bead firing dishes, vermiculite, and alumina hydrates are all used to support metal clay supplies or pieces with specific details like round, domed, or dimensional shapes that might deform during the firing process.
- Fiber blankets:
These also act as support elements, and they refer to thick sheets of cotton that can be used as a blanket or pulled apart to support oddly shaped items. Keep in mind that these will only last just a few firings before disintegrating.
Precious metal clay projects
Usually, precious metal clay artists display their skills in the form of jewelry. Earrings, pendants, rings, beads, and bracelets are just a few of the available options for people looking into working PMC.
It is also very common to introduce gems or stones into PMC designs, giving creators the possibility to embed colorful elements into their projects. Artists who are looking to experiment through this medium may also produce pieces that are a little bit out of the box: figurines, charms, and even coins can be produced through this method.
While working with metals usually requires a lot of expertise and skills, precious metal clay allows anyone to join in on the creative possibilities of metal, making it the perfect craft for even the most amateur of jewelers. All the different textures and details of clay plus the durability and strength of metals are all combined into one single medium that will impress artists everywhere.
