Air bubbles (sponge-like holes) in stick lipstick poured into mold

When making stick lipstick poured into a mold, the optimal temperature for pouring the lipstick base is very important. The ideal temperature depends on the ingredients in your formula, especially the types of waxes and oils used.

Generally, the lipstick base should be poured at a temperature slightly above the melting point of the highest melting ingredient (usually the wax) to ensure the base remains liquid and flows well into the mold without solidifying too quickly. However, the temperature should not be excessively high, as this can cause excessive shrinkage upon cooling or degrade some heat-sensitive ingredients.

A common temperature range for pouring lipstick is typically between 70-85 degrees Celsius, but this range is just a general guideline. The most accurate temperature should be determined based on the melting points of the ingredients in your specific formula and testing to find the optimal temperature that yields a smooth texture without air bubbles.

The problem of sponge-like holes in solidified lipstick is usually caused by air bubbles trapped within the lipstick base. The causes may include:

• Overly vigorous mixing: Whipping or stirring the ingredients too forcefully, especially as the base cools, can introduce air bubbles.
• Heating too quickly or unevenly: Can cause air bubbles within the base.
• Pouring at too low a temperature: If the base is too cool before pouring, it becomes too viscous, making it difficult for air bubbles to escape.
• Pouring too quickly or from too high a distance: Can cause splashing and introduce air into the lipstick.
• Not allowing the base to de-aerate: After mixing and heating, the base should be allowed to sit for a short period (while maintaining a pourable temperature) to allow air bubbles to rise to the surface.
• Mold is too cold: If the mold is too cold, when the hot base is poured in, the outer layer of the lipstick solidifies very quickly, trapping air bubbles inside.

Solutions for air bubbles (sponge-like holes):

1. Mix gently: Avoid vigorous whipping or stirring, especially as the base cools.
2. Heat slowly and evenly: Use moderate heat.
3. Pour at the appropriate temperature: Test to find the temperature that keeps the base liquid enough, not too viscous, and easy to pour.
4. Pour slowly and steadily: Pour the lipstick base smoothly into the mold, trying to pour as close to the mold opening as possible.
5. De-aerate the base: After mixing, let the base sit for about 5-10 minutes (while maintaining pouring temperature) to allow air bubbles to rise.
6. Check mold temperature: Use a mold at room temperature or slightly warmed (but not hot) before pouring.
7. Use a vibrator: If available, gently vibrate the mold after pouring to help air bubbles rise.

To provide more specific and accurate advice for your formula and process, the staff has requested detailed information about your formula and steps. Providing this information will help in analyzing the problem and recommending more targeted solutions.