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Sometimes when working with polymer clay it is not ideal to make and bake readily. Therefore, one might wonder how long to leave polymer clay before baking? This guide has complete instructions to assist you in keeping your clay properly for longer time if you plan to bake later.
How long to leave Polymer Clay before baking?
Polymer clay can sit for months or even years before baking, as long as it’s stored properly. It doesn’t dry out like air-dry clay because it cures only when exposed to heat. However, here are some things to keep in mind:
Short-Term (Days to Weeks)
- If you’re working on a project and leave it out for a few days or weeks, the clay will stay pliable as long as it’s not exposed to excessive heat or sunlight.
- Dust and lint can settle on the surface, so covering it with plastic wrap or a container is a good idea.
Long-Term (Months to Years)
- Unbaked raw clay can last for years if stored in an airtight container away from direct sunlight and heat.
- Pre-made projects can sit for months before baking, but the surface might collect dust or lose slight pliability if exposed to air for too long.
Storage Tips
- Temperature: Keep it at room temperature (around 60–75°F or 15–24°C).
- Avoid Plastic Bags: Use wax paper, glass jars, or plastic containers made from polypropylene (#5 plastic).
- Cover Projects: Use foil or cling wrap to protect from dust and lint.
Related: How Long to Bake Polymer Clay?
What to do if Polymer Clay becomes firm?
If your polymer clay has become slightly firm after sitting for a while, here are several ways to soften and revive it:
1. Condition by Hand
- Kneading: Start by warming the clay with your hands. The heat from your hands can soften it gradually.
- Rolling: Use a rolling pin or acrylic roller to flatten the clay, then fold and repeat.
2. Add Softening Agents
- Clay Softener: Sculpey Clay Softener and Fimo Quick Mix are liquid clay softeners. Just add a drop or two and knead it in.
- Mineral Oil or Baby Oil: Add a tiny amount (a drop at a time) and mix thoroughly.
- Mix with Fresher Clay: Blend older clay with fresh, soft polymer clay to restore pliability.
3. Warm It Up
- Body Heat: Hold the clay in your hands or keep it in your pocket for a while.
- Heating Pad: Place the clay in a plastic bag and set it on a low-temperature heating pad for 5–10 minutes.
- Warm Water: Place the sealed clay bag in warm (not hot) water for a few minutes.
4. Pasta Machine or Clay Conditioning Machine
Run the clay through a pasta machine several times to break it down and make it more flexible.
5. Last Resort: Food Processor
For extremely hard clay, use a dedicated mini food processor to break it down into crumbs. Then add a softening agent and knead it back together.
Softeners and Tools for Softening Polymer Clay
Here are some highly recommendations for softening polymer clay:
1. Clay Softeners
- Sculpey Clay Softener and Thinner: A few drops can restore firmness without altering color or texture.
- Fimo Mix Quick: A conditioning additive that blends with stiff clay to make it pliable.
- Cernit Magic Mix: Great for softening without making the clay sticky, also works as a liquid clay thinner.
2. Oils (Household Options)
- Mineral Oil: Inexpensive and gentle—ideal for softening small amounts.
- Baby Oil: Similar to mineral oil but scented, so use sparingly.
- Coconut Oil: Works well but can add slight greasiness if overused.
3. Tools for Conditioning
- Pasta Machine: A classic tool for conditioning clay. The Clay Conditioning Machine or Atlas 150 are popular.
- Acrylic Roller: Useful for manually flattening and folding clay.
- Clay Extruder: Helps condition hard clay by breaking it into smaller pieces.
4. Storage Helpers
- Polypropylene Containers: Airtight and safe for long-term storage. Look for the #5 recycling symbol.
- Wax Paper or Parchment: For wrapping clay pieces to prevent dust buildup.
Written by: Hani Shabbir
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