Cracks and sinkholes are common and quite frustrating to find in your candles.
Cracks can sometimes be a cosmetic issue, but if these cracks uncover sinkholes or craters, then you can be looking at a performance issue as well.
So why is this happening?
When candle wax cools, it shrinks. If this process happens too quickly, the wax can have trouble adhering to the container or wick, leading to cracks forming.
Another reason could be air bubbles. If the surface of your candle solidifies before air bubbles have had a chance to release, air will be trapped in the wax. This can create air pockets which will cause cracks and sinkholes.
How to Fix and Prevent Cracks and Sink Holes in Candles
Tap Container
Gently tap the candle container after pouring the wax to release air bubbles trapped in the wax.
Experiment With Your Pour Temperature
Pour temperature can be tricky because you can pour too hot or too cool.
If you pour at too low a temperature, the cooling process for the wax will be fast, and imperfections like cracks and sinkholes may form while the wax contracts.
If you pour too high a temperature, you can also run into problems. The higher the temperature you pour, the more the wax has to cool and the more the wax will shrink, leading to more opportunities for imperfections to form.
The right pour temperature will depend on your specific environment.
When you purchase wax, the manufacturer will have a recommended pour temperature. For example, 464 soy wax has a recommended pour temp of 135°F.
Use the recommended temp as the baseline and adjust up or down as needed by increments of 5 degrees.
Preheat Containers
Preheat the container to reduce the shock of hot wax pouring into a cold container.
Pouring hot wax into a cold container can shock the cooling process leading to adhesion problems, cracks, and sinkholes.
By heating the container, your candle will have an even cooling process helping with adhesion.
To heat your containers, you can use a heat gun or put your containers in the oven on a low setting (~100°F) for 2-3 minutes.
Don’t Stir Vigorously
Make sure you are gently stirring your wax.
Vigorously stirring your wax will create air bubbles. These air bubbles can lead to air pockets trapped in the wax during its cooling stage and can lead to cracks, sinkholes, and poor performance of your candle.
Slowly Pour the Wax
Slow and steady wins.
Slowly pour your wax to avoid creating air bubbles which can cause imperfections.
Melt the Surface of Candle
If you have minor cracks, you can melt the top layer of wax with a heat gun.
Put the gun on the lowest setting and evenly melt a thin surface layer. You may want to repeat once more to get a smooth top.
If you have some cracks and suspect sinkholes, poke some relief holes into the wax (typically, these sinkholes form around the wick). Use a chopstick or something similar to poke a hole and expose any air pockets or craters lingering beneath the surface.
Then use your heat gun to melt the top layer of wax, which will fill in the relief holes you made.
Do an Additional Pour
Poke relief holes around the wick with a chopstick or something similar in shape. Do this while your wax is still warm but has the appearance of being solid.
Melt additional wax and pour it into the holes you’ve made.
For the wax used to fill in the holes, melt it to the same temperature as the original wax you poured.
Store Candles in Warmer Environment
If you’re in a cold climate, insulate and cure your candles in a warmer environment.
Try storing them inside a box but make sure they have a few inches of separation between each candle while they cool. Once completely cooled, you can store them for curing without worrying about the separation between each candle.
Conclusion
It may be frustrating to see cracks and sinkholes in your candles, but the good news, it’s not the end of the world.
To prevent or fix cracking imperfections in your candle, you can:
- Tap the container after pouring to release air bubbles.
- Gently stir the wax to avoid creating air bubbles.
- Gently pour your wax to avoid creating air bubbles.
- Experiment with pouring your wax at different temperatures.
- Preheat candle containers for a smoother cooling process.
- Melt the surface layer of the candle to repair cracks.
- Create relief holes in your candle while it’s still warm and fill in with an additional pour of wax or by melting the top layer of wax with a heat gun.
- Store your candles in a warmer environment while they cure.