Yes, air dry clay will generally break down and disintegrate when submerged in water.
Air dry clay, unlike polymer clay or kiln-fired clay, doesn't undergo a chemical transformation when it dries. Instead, the water within the clay evaporates, leaving behind hardened clay. This hardened clay is still water-soluble, meaning it can be rehydrated and softened. Prolonged exposure to water will cause it to soften, lose its shape, and eventually break apart.
Here's a breakdown:
- Softening: Initial contact with water softens the clay. This is why you can add water to air dry clay to rework it.
- Structural Weakness: As more water is absorbed, the clay's structure weakens. The bonds holding the clay particles together are broken.
- Disintegration: Eventually, the clay will become a slurry and lose all form, effectively breaking down completely.
Factors influencing how quickly it breaks down:
- Clay Type: Some brands or types of air dry clay may be slightly more resistant to water than others, but all are susceptible.
- Size and Thickness: Smaller, thinner pieces will break down faster than larger, thicker ones.
- Water Temperature: Warmer water may accelerate the breakdown process.
- Water Agitation: Still water will result in slower degradation compared to agitated water.
Preventing Breakage:
The only reliable way to make air dry clay waterproof is to seal it thoroughly with a waterproof sealant. Several coats are often required. However, even with sealant, prolonged submersion is not recommended.