Can You Erase An Underglaze Pencil?

What Are Underglaze Pencils?

Underglaze pencils are coloring tools used in ceramic arts and pottery. They are made from underglaze pigments mixed with a wax or oil-based binder to create a pencil-like consistency that can be used to draw and decorate pottery pieces before firing.

Underglaze pencils allow ceramic artists to add detailed decorative designs, patterns, and illustrations directly onto bisqueware, greenware, or raw clay (source). The underglaze colors are absorbed into the clay body for a permanent graphic decoration after firing.

Common uses for underglaze pencils include:

• Drawing fine lines, shapes, and detailed imagery
• Adding handwritten words, signatures, or greetings
• Shading delicate coloring effects
• Outlining areas to be painted with underglazes

Underglaze pencils come in a variety of types:

• Standard pencils with a wooden casing and pointed core
• Water-soluble pencils that can be blended with water
• Square or chiseled shaped pencils for special effects
• Jumbo pencils for bolder lines

Can You Erase Underglaze Pencil Marks?

Underglaze pencil marks can be challenging to erase completely, especially once the ceramic piece has been fired in a kiln. The colorants in underglaze pencils are designed to permanently fuse with the glaze during firing, so it’s impossible to remove the marks after this point.

Before firing, it is possible to erase underglaze pencil, but the process is more difficult compared to erasing regular graphite pencil. The pigments are formulated to adhere well to bare and bisque fired clay surfaces, so they tend to stain the clay even after erasing.

There are a few techniques that may help remove underglaze pencil marks before firing:

• Use a slightly damp sponge or magic eraser to gently rub the area and lift some of the pigment
• Try a ceramic pencil eraser, which is more abrasive for removing stains
• Lightly smooth the surface with fine grit sandpaper



• Cover with a clay slip to hide any remaining discoloration

Taking precautions like using a light touch when drawing or putting down a layer of wax first can also help minimize staining. But some ghosting of the original marks may still be visible. Planning out designs carefully and avoiding errors is advisable when working in underglaze pencil.

Removing Marks Before Firing

There are a few techniques you can try to remove underglaze pencil marks before firing your ceramic piece:

Blotting the area with a paper towel or soft cloth can help lift some of the pigment while it’s still wet. Gently rubbing or abrasion may remove additional material.

Solvents like turpentine or alcohol can dissolve the binders in underglaze pencil and allow you to wipe away the mark. Take care not to oversaturate the piece.

Light sanding with fine grit sandpaper may remove pencil lines, but take care not to scratch the bisque surface. Start with 220 grit or higher.

While these techniques may reduce the appearance of pencil lines, it can be difficult to completely erase underglaze pencil prior to firing. Marks may remain visible even after efforts to remove them. Planning your decoration technique in advance helps avoid the need for erasing.

Working Around Mistakes

If you happen to smudge or make a mistake with your underglaze pencil, there are a few ways to work around it:

Incorporate the smudges or errors into the overall design. Underglaze has a fluid, organic look when smudged that can be used artistically in some cases. Lean into “mistakes” and make them part of the aesthetic.

Paint over any errors with additional underglaze or slip. Let it fully dry and start again on the new surface. Multiple thin layers of underglaze pencil can build up vibrancy of color. According to a post on Reddit, sanding the bisqueware first will help underglaze adhere to the surface better.

If needed, start over with a new bisque piece. Underglaze pencil can be difficult to fully remove from porous bisqueware if the layer is too thick. When working on an important commission or show piece, it may be best to scrap the test and begin again on a fresh start.

Preventing Smudges

There are a few techniques you can use to help prevent smudging when using underglaze pencils:

Let each layer of underglaze fully dry before adding another layer or moving on to glazing. Underglaze dries quickly, but giving it at least 10-15 minutes to set will help prevent smudging. Be patient and avoid rushing.

Use light pencil pressure when applying underglaze. Heavy pressure can lead to thicker application that takes longer to dry and is more prone to smudging. A light touch will allow for clean, precise lines.

Make sure your hands are clean before handling pieces with underglaze pencil. Oils from skin contact can cause underglaze to run or smear.

Apply a fixative spray after underglazing and before glazing such as Krylon Workable Fixatif Spray. This seals and protects the underglaze layer so glazes can be applied without disturbing the underglaze.

Alternative Mark Making Tools

While underglaze pencils are a popular choice for ceramic decoration, there are other mark making tools that can achieve similar effects:

Watercolor pencils are a good alternative as they can create subtle details and shading like underglaze pencils. The main difference is they are applied over an already fired glazed surface rather than raw clay. Popular brands like Derwent and Caran d’Ache make watercolor pencils safe to use at high temperatures.

Chalk pencils and pastels can also mimic the soft, dusty look of underglaze pencil. Oil-based chalks and pastels may burn out in firing, so ceramic artists prefer wax or water-soluble options. These can be used on greenware or bisque ware before glazing.

Markers with ceramic ink are convenient for making bold, graphic marks similar to underglaze pencil. Brands like Pentel Arts and Sharpie make markers formulated for high heat applications.

Ink applied with brushes, droppers, or pens can produce delicate line work or shading like underglaze pencils. India ink and ceramic stains are commonly used. Test ink on a bisque tile before applying to pieces to ensure it will not burn out.

Firing Process for Underglaze

The firing process for underglaze depends on whether it is low-fire or high-fire underglaze. Underglaze is formulated to mature at specific temperature ranges.

Low-fire underglaze is designed to be fired between cone 06 and cone 04, which corresponds to temperatures between 1728-1945°F (940-1063°C). Low-fire underglaze will melt and fuse to the clay body between these temperature ranges. The process usually takes 4-6 hours to complete in an electric kiln.

High-fire underglaze is designed for cone 6 firings around 2200°F (1204°C). It requires a longer, hotter firing around 8-12 hours to fully fuse the underglaze to the clay body. High-fire underglaze results in more vibrant, durable colors.

It’s important to match the correct underglaze formulation with your planned firing temperature. Underglaze fired too low may fail to fuse properly. If fired too high, it can burn out and fade away.

Underglaze is applied before the final glaze firing. Once matured at the ideal temperature, the underglaze will become permanent beneath a transparent glaze.

After Firing

Once an underglazed piece has been fired, the underglaze color is permanently affixed to the clay surface. There is no way to remove specific underglaze pencil marks from a finished, fired ceramic piece.

Underglaze pencils fuse with the clay body during firing, so their marks become an integral part of the pottery. The pigments in the pencils chemically interact with ingredients in the clay body to create a permanent bond.

According to ceramic arts expert John Britt, “Once fired, underglazes are permanent. The only way to remove underglaze color from a fired piece would be to sand the entire surface.” (Source)

So while underglaze pencil marks can be erased or cleaned from greenware or bisqueware before firing, they are indelibly baked into finished pottery and ceramic sculptures after the firing process. There is no way to selectively remove or undo specific underglaze pencil strokes from a fired ceramic piece without mechanically abrading the entire surface.

Caring for Underglaze Pieces

Caring for pottery that has been decorated with underglaze requires some special considerations. Underglaze decoration sits under a layer of clear glaze, which provides protection for the design. However, the glaze can become compromised over time with use, so it’s important to handle underglaze pieces with care.

Experts recommend handwashing underglaze pottery. The abrasives in dishwasher detergent can slowly wear away at the glaze and expose the underglaze beneath over repeated washings. Gentle handwashing allows you to carefully clean the piece without adding extra stress to the glaze.

You’ll also want to avoid using abrasive cleaners or scrubbers when washing underglaze pieces. Scouring pads, steel wool, and rough sponges can scratch the glaze. Stick to soft cloths and sponges instead.

With use, the protective glaze layer may become compromised. It’s a good idea to periodically reapply a thin layer of clear glaze to your favorite underglaze pieces to renew the protection. This will help prevent the underglaze from becoming exposed or damaged during everyday use.

By treating underglaze pieces gently and taking steps to preserve the glaze, you can keep your hand-decorated pots looking beautiful for years to come.

Key Takeaways

When working with underglaze pencils, it’s important to understand that their marks cannot be erased once the piece has been fired in a kiln. However, there are some techniques for dealing with mistakes before firing:

– Plan out your design carefully to prevent errors. Use light guidelines in pencil if needed.

– Blot up wet underglaze quickly using a damp sponge or towel. This can lift some of the color.

– Use painters tape to mask off areas you want to protect from smudging.

– Sand wet marks gently with fine grit sandpaper to remove the color.

– Avoid overworking an area as this can rub the underglaze into the clay body.

While underglaze pencil is semi-permanent prior to firing, once cured in the kiln, the marks are fixed permanently into the glaze. At this stage, the only way to remove the color is by grinding away the finished surface glaze.

With planning and care, underglaze pencils can create beautiful, vibrant results. Their semi-permanent nature before firing allows for fixing small mistakes. But for best success, underglaze is an unforgiving medium requiring forethought and attention to detail.