Best Sealants to Use Alongside Pottery Glazes

When it comes to creating durable, beautiful ceramics, glaze plays an integral role in both aesthetics and functionality. However, even the best pottery glaze sometimes benefits from an additional sealant layer to enhance durability, prevent water absorption, and improve the overall finish of the piece. Choosing the right sealant to use alongside pottery glazes can be a game-changer for potters, especially those aiming for longevity and professional-quality results.

In this article, we’ll explore the best sealants to use alongside pottery glazes, their applications, advantages, and considerations. Whether you’re a beginner or an experienced ceramic artist, understanding these options will help you elevate your craft.

Why Use a Sealant Alongside Pottery Glazes?

Pottery glazes are primarily made from silica, fluxes, and colorants that melt during firing to form a glass-like coating on ceramic pieces. While glazes create a protective barrier and add aesthetic appeal through colors and textures, they are sometimes porous or prone to micro-cracking depending on the firing process or glaze composition.

Here are some reasons why adding a sealant after glazing might be beneficial:

• Enhanced Water Resistance: Some glazes may not be fully waterproof, especially low-fire or crackle glazes. A sealant adds an extra layer of protection against moisture penetration.

• Protection Against Stains and Residue: Sealants can help prevent oils, dirt, or food residue from penetrating porous glaze surfaces.

• Improved Durability: Sealants can guard against chipping, scratching, or surface crazing by reinforcing the glaze surface.

• Increased Gloss or Matte Finish: Depending on the sealant used, you can modify the surface finish, adding glossiness or reducing shine.

• Food Safety Concerns: Certain sealants can ensure that non-food-safe glazes become safe for use with food items by preventing leaching of harmful materials.

However, it’s important to note that not all glazes require or benefit from sealants. Some high-fired stoneware and porcelain glazes are sufficiently impermeable and durable on their own. Sealants are more commonly used with low-fire pieces, decorative items not intended for heavy use, or restorations.

Key Factors to Consider When Choosing a Sealant

Before diving into specific products and types of sealants, consider these factors:

• Compatibility with Glaze Type: The sealant must adhere well without altering or damaging the glaze surface.

• Intended Use of the Pottery: Food contact items require non-toxic and food-safe sealants.

• Finish Desired: Glossy vs matte; some sealants enhance shine while others reduce it.

• Durability Needs: For functional ware that will see wear-and-tear versus decorative pieces.

• Application Method: Brush-on, spray-on, dipping, ease of use matters depending on your workshop setup.

• Drying/Curing Time: Some sealants dry quickly; others require extended curing periods.

• Environmental and Health Safety: Preference for non-toxic, water-based products.

Best Sealant Options to Use Alongside Pottery Glazes

1. Clear Epoxy Resin

Overview:
Clear epoxy resins are two-part polymer coatings widely appreciated for their hard, durable finish. When applied over pottery glazes, epoxy resin creates a thick, glassy surface that is waterproof and resistant to scratching.

Advantages:

• Excellent water resistance
• High durability and chip resistance
• Adds a deep glossy finish that enhances colors beneath
• Can fill minor surface imperfections

Considerations:

• Usually not food safe unless specifically labeled as such
• Requires mixing two components accurately
• Longer curing time (typically 24-72 hours)
• Can yellow over time if exposed to sunlight
• Proper ventilation needed during application

Best Used For:

Decorative pottery pieces such as sculptures or vases where durability and gloss are prioritized over food safety.

2. Acrylic Polymer Sealers

Overview:
Acrylic polymer sealers come in both water-based and solvent-based forms. They are commonly used in fine arts as varnishes but also serve well in ceramics by providing a transparent protective layer over glaze surfaces.

Advantages:

• Available in gloss, satin, and matte finishes
• Water-based varieties are low odor and non-toxic
• Dries quickly
• Easy application with brushes or sprays
• Generally flexible coatings help resist cracking

Considerations:

• May not offer as thick or tough protection as epoxy
• Not always food-safe unless specifically formulated
• Could slightly alter the appearance of some glazes (e.g., darkening)

Best Used For:

Functional pottery that does not require heavy wear resistance but benefits from added moisture protection; also suitable for decorative pieces.

3. Food-Safe Ceramic Sealers

Overview:
Several manufacturers produce specialized sealants designed explicitly for ceramic tableware. These coatings pass FDA regulations for food safety and can be applied over glazed surfaces to prevent leaching in lower-fired ceramics.

Advantages:

• Certified non-toxic and safe for direct food contact
• Penetrates minor micro-pores sealing the surface effectively
• Typically water-based and odorless
• Maintains original glaze appearance without yellowing

Considerations:

• Often requires reapplication after extended use
• Less impact on gloss level; primarily functional protection
• May involve multiple coats with drying time between applications

Best Used For:

Low-fire pottery used as plates, bowls, mugs where glaze lacks full vitrification but food safety is critical.

4. Wax-Based Sealants (Microcrystalline Wax)

Overview:
Wax coatings have been used historically on pottery surfaces to create water repellency. Microcrystalline waxes provide a thin protective layer when buffed onto glazed ceramics.

Advantages:

• Adds subtle sheen without dramatically changing color
• Easy to apply with cloth or brush
• Provides temporary moisture resistance
• Can be buffed or removed easily if needed

Considerations:

• Not durable long term; wears off quickly with washing
• Not suitable for functional tableware needing sustained protection
• Attracts dust if left unbuffed properly

Best Used For:

Decorative pottery or pieces needing short-term sealing; ideal for outdoor garden pots or display items.

5. Silane/Siloxane-Based Sealers

Overview:
Silane/siloxane solutions penetrate porous ceramic surfaces forming hydrophobic barriers inside rather than just coating the surface externally. Originally developed for masonry waterproofing, these can work well on porous low-fire ceramics.

Advantages:

• Penetrates deeply sealing pores inside glaze cracks or crazing
• Allows vapor permeability while blocking liquid water absorption
• Invisible finish that preserves original look of glaze
• Durable once cured

Considerations:

• Generally not food-safe; better suited for decorative ware
• Application requires proper ventilation and often multiple coats
• May take days to cure fully depending on humidity/temperature conditions

Best Used For:

Porous stoneware vases or decorative tiles exposed to moisture but not intended for food use.

Application Tips for Using Sealants Over Glaze

To maximize effectiveness when applying any sealant over pottery glaze:

1. Ensure Cleanliness: Wash pieces thoroughly to remove dust, oils, or residues before sealing.
2. Test First: Always test your chosen sealant on a sample piece with similar glaze to observe results.
3. Apply Thin Layers: Multiple thin coatings generally perform better than one thick coat.
4. Follow Manufacturer Instructions: Pay attention to recommended drying times and environmental conditions.
5. Avoid Contamination: Use clean brushes/tools and avoid touching glazed surfaces before sealing.
6. Handle Curing Carefully: Some products require curing at specific temperatures; ensure proper conditions.
7. Consider Reapplication Needs: Certain sealants may wear off over time, plan maintenance accordingly.

Final Thoughts

While many potters rely solely on firing techniques and glaze chemistry to achieve optimal finishes, supplementing pottery glazes with suitable sealants offers an additional level of protection and aesthetic enhancement. Choosing the best sealant depends heavily on your specific project goals, whether durability, food safety, finish type, or ease of application.

For decorative ceramics where durability and gloss are essential but food contact is unnecessary, clear epoxy resin stands out as a top choice due to its toughness and depth of finish. Acrylic polymer sealers provide versatility with easier handling but somewhat less rugged protection. Food-safe ceramic sealers fill an important niche for functional ware needing extra assurance without compromising safety.

Ultimately, experimentation combined with careful observation will guide you towards the ideal combination of glaze and sealant tailored perfectly to your artistic vision and practical needs.

By investing time into understanding these materials now, you’ll significantly enhance both the quality and lifespan of your pottery creations, making each piece truly stand out!