How to prevent air bubbles in cast concrete outdoor armchairs?

Air bubbles in cast concrete outdoor armchairs can ruin the finish and weaken the structure. To prevent them, follow these steps:

1. Proper Mixing: Ensure the concrete mix is well-blended but not over-mixed, as excessive agitation can trap air. Use a low-water-content mix to reduce porosity.

2. Vibration: Use a vibrating table or handheld vibrator to release trapped air bubbles. Gently tap the mold sides if tools aren’t available.

3. Slow Pouring: Pour the concrete slowly and at an angle to minimize air entrapment. Avoid dropping the mixture from a height.

4. Mold Preparation: Coat the mold with a release agent and ensure it’s clean and dry. Smooth surfaces reduce bubble formation.

5. Curing: Cover the cast with plastic and keep it moist for 24–48 hours to prevent rapid drying, which can exacerbate bubbles.

By following these techniques, you’ll achieve a smooth, durable finish for your outdoor concrete armchairs.