Air-dry clay is a fantastic medium for artists and hobbyists, but many wonder: Is air-dry clay waterproof? The short answer is no—but with the right sealing techniques, you can protect your creations from moisture damage. In this guide, we’ll explore how to waterproof air-dry clay, ensuring your sculptures and pottery last for years.

Does Air-Dry Clay Need to Be Sealed?

Unlike kiln-fired ceramics, air-dry clay remains porous even after drying. If exposed to water, it can soften, crack, or completely disintegrate. Sealing is crucial to protect your pieces from humidity, spills, and outdoor conditions.

Good news: With the right sealer, air-dry clay can become water-resistant!

How to Waterproof Air-Dry Clay

1. Choose the Best Sealer for Air-Dry Clay

There are different types of sealants depending on the level of waterproofing you need:

• Mont Marte Natural finish Clay Sealer– A non-toxic, water-based sealer designed specifically for air-dry clay.
• Acrylic Spray Sealers – Great for decorative protection.
• Polyurethane Varnish – Best for outdoor exposure.
• Epoxy Resin – Provides full waterproofing.
• Mod Podge – Offers light protection but is not fully waterproof.

2. Preparing Air-Dry Clay for Sealing

• Allow full drying time (24-72 hours).
• Sand rough edges for a smooth finish.
• Remove dust with a damp cloth or soft brush.

3. How to Apply a Waterproof Sealant

Using Mont Marte Natural Finish Clay Sealer

• Apply a thin, even layer with a soft brush.
• Allow to dry for 30 minutes before applying a second coat.
• Use 2-3 coats for maximum protection.

Acrylic Sealers (Best for Indoor Use)

• Apply 2-3 thin coats.
• Allow full drying between layers.
• Finish with a clear coat for added durability.
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Epoxy Resin (Best for Waterproofing)

• Mix resin according to instructions.
• Brush a thin layer over your piece.
• Let cure for 24-48 hours.

Polyurethane or Varnish (Best for Outdoor Use)

• Choose a UV-resistant, water-resistant varnish.
• Apply 2-3 coats, allowing drying between layers.