How Do You Use Mason Stains In Pottery?

Mason stains are ceramic stains made specifically for pottery and ceramic work. They are manufactured by companies like Mason Color Works, which has been producing high quality ceramic stains since 1842 (https://www.masoncolor.com/mason-color-history). Mason stains allow potters to add color to their work in a controlled and predictable way.

Mason stains work by using metal oxides and other inorganic pigments that can withstand the high temperatures of firing clay or glaze. When added to clay or applied under a glaze, mason stains provide vibrant, permanent colors. They are a versatile option for potters looking to decorate, accent, or add color to their finished pieces.

Some key benefits of using mason stains in pottery are:

• Wide range of colors from a single stain manufacturer
• Color consistency between batches
• Stable colors that resist fading
• Ability to mix, layer, and blend colors
• Compatibility with various clays and firing methods

With their longevity, brilliance, and versatility, it’s no wonder mason stains have become a staple in many potters’ studios.

Types of Mason Stains

There are two main categories of mason stains – chrome-based stains and non-chrome stains. Chrome-based stains offer bright, vibrant colors but contain toxic chemicals, while non-chrome stains have more muted earthy colors but are non-toxic. Common color options for chrome stains include brilliant blues, grass greens, tomato reds, and sunny yellows. Non-chrome stains come in colors like terra-cotta, sage, plum, and pistachio.

In addition to regular mason stains, there are also specialty options like lusters. These contain small flecks of mica that create a shimmering, iridescent effect. Lusters come in various colors like pearl, opal, iris and labradorite. They add a unique look that catches and reflects light beautifully.

So in summary – chrome stains offer bright colors but require safety precautions, non-chrome stains have earth tones and are non-toxic, and lusters add special shimmering effects.

How Mason Stains Work

Mason stains are colored pigments made of metal oxides, carbonates, and other inorganic materials that are finely ground into a powder. They are formulated to bond with clay bodies through an ionic exchange that occurs during firing. The metal ions in the mason stain powder interact and swap places with ions in the clay, allowing the colorant to become part of the clay matrix.

The composition and chemistry of mason stains allow them to provide vibrant colors and integrate into the clay body permanently after firing. They are made to be used at high temperatures and flux into the clay rather than burning out. The particle size of mason stains is optimized for maximum saturation of color.

Mason stains have some limitations depending on the composition of the clay body. For example, dolomite clay can inhibit the ion exchange that allows mason stains to bond properly. Some stains also interact differently with iron-rich red clays versus white clay bodies. Testing stains on test tiles is advised to ensure good results.

Preparing Clay for Stains

It is important to bisque fire clay before applying mason stains. Bisque firing opens up the clay body so it becomes porous and allows the stains to soak in evenly. Non-porous clay will cause stains to sit on the surface and flake off. Mason stains work best on low-fire porous clay bodies like earthenware.

For non-porous clays like porcelain or stoneware, apply a porous engobe or slip before adding stains. A white engobe allows the true colors of the stains to show through. Apply the engobe to raw clay and bisque fire before adding stains. The engobe soaks up the stains and adheres to the non-porous clay body. Using a slip is another option for priming non-porous clay. See this article for recipes and instructions: [http://www.ccpottery.com/colored-clay-lessons–chris/how-to-color-clay-with.html]

Bisqued clay is ready to accept mason stains evenly for vibrant, consistent color. Whether using porous earthenware or priming with engobe/slip, proper bisque firing and surface preparation is the key to success with mason stains.

Applying Mason Stains

There are several techniques for applying mason stains to clay pieces including brushing, dipping, and spraying. It’s important to get even coverage when applying stains. Uneven staining will result in a patchy and unattractive finish.

Brushing stains directly onto the clay is the most common method. Use a soft brush and apply the stain in smooth, even strokes. Multiple thin layers tend to work better than a single thick coat. Let each layer dry completely before adding another. Brushing allows for precise control and is great for detailed decorations.

Dipping involves submerging the clay piece into a container of diluted stain. This can provide quick, full coverage but it’s difficult to achieve an even stain. Rotate and tilt the piece while dipping to cover all sides. Consider wearing gloves to protect your hands.

Spraying stain through an airbrush or spray bottle achieves a soft, blended effect. Work in light layers, building up intensity gradually. Position the piece at different angles to coat all surfaces evenly. Spraying requires some skill but creates a smooth professional finish.

Layering multiple colors of stains on top of each other expands your options for custom designs. Allow the first color to fully dry before adding another. The underlying stain will affect the final mixed color. Test layers on a tile first to perfect your technique.

Cite: https://www.georgies.com/pdfs/Mason-Stain-Class.pdf

Sealing Mason Stains

Once mason stains have been applied to clay and allowed to dry, they must be sealed in prior to firing. The most common sealant used with mason stains is a clear glaze. Clear glazing creates a glassy surface that keeps the mason stains from burning out in the kiln. It also protects stained pieces from fading over time with use.

The main benefit of using a clear glaze to seal in mason stains is that it fully protects the stains and allows the natural texture of the clay body to show through. The downside is that clear glazing requires an additional step after staining – the piece must be dipped or brushed with glaze then allowed to dry before firing.

Alternatively, some potters choose to use a colored glaze over top of stains instead of clear glazing. This eliminates a step, as the colored glaze can be applied in one firing after stains. However, the drawback is that colored glazes cover up the natural clay texture and can mute or alter the stained colors. Colored glazes must be tested to ensure compatibility with the mason stains used.

Other options for sealing in mason stains include using a transparent overglaze or even a spray acrylic sealer on low fired earthenware pieces. Overglaze creates a glossier surface than clear glaze, while acrylic can yellow over time. Test options to determine the best sealant for the desired results.

Firing Pieces with Stains

When firing pottery pieces with mason stains, it’s important to fire to the ideal temperatures to achieve vibrant colors and avoid issues. Mason stains require specific cone temperatures depending on the type of stain.

Most mason stains will achieve their full color potential at cone 5-6 temperatures (2165-2185°F). Firing to lower temperatures may result in paler or muted colors. For example, firing an iron oxide red stain to cone 04 will produce an orangey color vs the full red at cone 5. Over-firing stains can also cause issues – firing higher than cone 6 may cause colors to burn out or become muddy. Always test fire samples first to ensure desired results.

Using witness cones in the kiln is recommended when firing mason stains. Witness cones bent to the proper angle will indicate that the kiln reached the target temperature for the stains. Keeping detailed notes on firing temps, witness cone results, and the color outcomes will help determine the ideal firing profile.

In summary, firing pottery with mason stains requires carefully monitoring kiln temperatures and using witness cones to achieve the most vibrant colors from the stains. Testing samples first is key to determine the optimal firing range.

Advanced Techniques

Mason stains open up many possibilities for advanced decorative techniques when using resists, mixing custom colors, and combining with underglazes or slip trailing.

One popular advanced technique is to use wax or latex resists to block out areas before applying mason stains. The resist prevents the stain from reaching the clay beneath, allowing you to reveal decorative patterns after removing the resist. Resists can be painted on in detailed designs, or you can spread wax over the entire piece then scratch through it to create textured effects.

You can also mix custom stain colors by blending two or more mason stain powders together before adding to clay or dipping your piece. Keep notes on blend ratios so you can recreate colors. Refer to a color mixing chart to help determine which stains to combine for your desired shades.

Mason stains pair beautifully with colored underglazes and slip trailing. For example, you can trail black slip over a red stained area to create dark accent lines. Or brush blue underglaze over light green stained sections. Experiment with layering and combining colored stains and underglazes to achieve unique multi-toned finishes.

Always test combinations on test tiles before applying to your final piece. Mason stains offer limitless potential for creativity when using advanced techniques.

Troubleshooting Issues

When using mason stains, some common issues that can arise are color bleeding, spots or runs in the stain, and firing faults that affect the final color. Here are some tips for troubleshooting these problems:

Fixing Color Bleeds

If you notice colors from your mason stains bleeding into areas where they aren’t wanted, there are a couple potential causes. First, the clay may have been too wet when the stains were applied, allowing them to spread. Letting clay dry more thoroughly before staining can help. Second, overlapping colors before firing can lead to blending. Be sure to leave space between different colored stains. If bleeding persists, try sealing the stains after applying them but before firing by spraying with a light coat of clear glaze.

Refer to: https://www.sheffield-pottery.com/Mason-Stains-Frequently-Asked-Questions-s/354.htm

Preventing Spots and Runs

Spots or runs of color in fired pieces often occur because the stain was not fully sealed before firing. Be sure to apply a transparent overglaze or clear coat over the stains prior to firing. Multiple thin layers tend to seal better than a single thick coat. Let each layer dry fully before adding the next. Runs can also happen if stains are applied too thickly in any single layer. Build up color gradually with multiple thin layers.

Refer to: https://www.masoncolor.com/frequently-asked-questions

Dealing with Firing Faults

Issues like colors changing unexpectedly during firing are often due to interactions with the clay body chemistry or glazes. Try testing the stain on test tiles before applying to a finished piece. Compare results at different temperatures or in oxidation vs reduction atmospheres. Record glaze and clay recipes to identify possible reactions. Adding extra calcium to the glaze may help stabilize some colors. If issues persist, consult an expert for advice.

Refer to: https://community.ceramicartsdaily.org/topic/21481-mason-stain-troubleshooting/

Safety Considerations

When working with mason stains, there are some important safety precautions to take into account. Some of the key things to be aware of are:

Toxicity concerns – Some mason stains contain heavy metals like cobalt, copper, manganese, and chromium which can be toxic if inhaled or ingested in powder form. It’s important to avoid breathing in stain dust by wearing a protective mask. Direct skin contact should also be avoided by wearing gloves. Refer to safety data sheets for toxicity details on specific stains (https://www.masoncolor.com/sites/masoncolor.com/files/mason_color_works_sds_6236.pdf).

Proper handling – Mason stains should be handled carefully to avoid spills and contamination. Work in a well-ventilated area and clean up any spills right away. Keep containers tightly closed when not in use.

Disposal – Leftover stains should not be washed down the drain or discarded in regular trash. Check for hazardous waste disposal options in your local area to properly dispose of mason stains.

Ventilation – When mixing dry stains or spraying stain slips, work in an area with excellent ventilation to avoid breathing in stain dust. Use a ventilated spray booth if possible. Allow pieces to thoroughly dry before handling to avoid exposure to wet stains.

With proper safety gear and careful handling, mason stains can be used safely. But being informed about the toxicity and taking precautions is critical. Refer to safety data sheets and follow all recommended handling guidelines.