When casting decorative items, figurines, or DIY projects, air bubbles often spoil the result. In this article, we'll show you 8 simple and effective ways to avoid air bubbles in casting compound—from the stirring technique to using our bubble scraper.
Anyone who creates creative objects with casting clay—be it for decoration, model making, or DIY projects—knows the problem: After demolding, unsightly air bubbles appear, spoiling the result. In this article, we'll show you the most common causes of air bubbles and offer practical tips on how to reliably avoid them.
🫧 Why do air bubbles form when pouring?
Air bubbles in casting material are usually caused by:
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stirring too vigorously or quickly
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Inclusions when pouring into the mold
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insufficiently vented casting compound
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Temperature fluctuations during drying
Depending on the material (e.g. plaster, concrete, Keraflott or other casting materials) the behavior can vary – but the basic principles are similar.
✅ 8 tips to prevent air bubbles in casting compound
1. Mix properly
Stir the mixture evenly and slowly, preferably with a spatula or hand mixer on low speed. Avoid rapid beating, which introduces air into the mixture.
2. Let it rest briefly before watering
Let the mixed casting mixture stand for 1-2 minutes so that air bubbles can rise on their own.
3. Pour thinly and build up slowly
Instead of pouring the entire mixture in at once, pour slowly in a thin stream and gently swirl the mold so that the mixture reaches all corners.
4. Use vibration
Gently tap the filled mold on the table or use a vibrating plate to force air bubbles to the top.
5. Pay attention to the material temperature
Do not process the casting compound when it is too cold – room temperature (18–22 °C) is ideal. Cold compound is more viscous and more prone to air pockets.
6. Remove blisters specifically – with the blister scraper from Lillify
For delicate details or hard-to-reach areas: With the small bubble scraper from our shop, air bubbles can be pushed out of corners and gaps – without damaging the mold.
7. Choose the right casting compound
Some products are formulated to be finer and more flowable – pay attention to the manufacturer’s instructions (“self-venting”, “suitable for delicate shapes”).
8. Patience when demolding
Allow the mold to fully harden before removing it. Removing it too early may rupture hidden bubbles.
🎯 Conclusion
Air bubbles in casting compound can be easily avoided with the right technique. A steady approach, patience—and the right tools—ensure clean, smooth results. Particularly helpful are small tools like our bubble scraper , which allows you to reach problem areas.
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