Sinkholes can be a pretty frustrating outcome when you’ve literally and figuratively poured hours of labour and love into your candle creation. So, what are sinkholes? How can you prevent them? And how can you fix them if they do happen? 

What are sinkholes? 

Sinkholes are craters, tunnels or pockets of air that get trapped or form in the wax of your candle as it sets - which can cause BIG problems during the course of your candle’s burn.

Naturally, wax shrinks as it cools and hardens in your vessel.  A large variance in temperature from pouring to when your candle is cooled and set creates an environment for sinkholes to form. This is because wax cools faster on the outside of the vessel than it does in the middle - where heat stays trapped and takes longer to dissipate. This can cause air bubbles to get trapped or the wax to start pulling apart from itself, ultimately creating sinkholes. Harder waxes like votive and pillar waxes are more prone to creating sinkholes since they require a higher melting point whereas softer waxes don’t require as high of a temperature and have less variance from pouring to when your candle is set.  

As we mentioned, sinkholes can cause lots of problems during the course of your candle’s burn so they’re not just an aesthetic issue. Sinkholes can affect how your candle burns or sometimes prevent it from burning altogether. For example, it can cause your wax to fall into the sinkhole as it melts, leaving nothing for the wick to burn other than itself. This can also cause the wick to burn too quickly and eventually drown your wick out once the wax does fully melt. It can also cause uneven heating in your vessel if a sinkhole directly exposes your vessel to the flame creating risk of your vessel overheating and shattering. So, make sure you keep reading to understand how you can prevent sinkholes or fix them if they have occurred! 

How can I prevent sinkholes? 

The biggest factor in the formation of sinkholes is temperature. That’s why it’s important to control the temperature variance as much as possible. There are a few different ways you can achieve this. 

1. The room temperature of your workspace should be around 21°C and you should keep your candles away from windows in the winter and AC vents in the summer. 
2. Make sure your vessels are at or above room temperature before pouring. Let them come to room temperature by leaving them in your workspace for approximately 15-20 minutes. Alternatively, you can warm up your vessels by putting them in the oven on the lowest setting (120-160°F) while your wax melts or hitting them with a hair dryer or heat gun to warm the vessel prior to pouring.
3. Avoid cooling your vessels on a cold surface like marble or stainless steel. If possible, use a cooling rack to set your candle creations with at least 4 inches of space between each vessel. This allows for proper air flow and ensures that you’re not creating hot spots from the warmth of the other cooling vessels. 

But temperature isn’t the only factor. Here are a few other things to consider: 

1. Make sure your vessels are clean and dry before pouring. We recommend cleaning your vessels with rubbing alcohol, rinsing them out with water and then letting them completely air dry before using. 
2. Mix your candle's ingredients gently. Mixing your ingredients too vigorously can cause you to trap air bubbles inside of your mixture. 
3. Slowly pour your wax into your vessel. Similar to mixing your ingredients too vigorously, pouring too quickly can also trap air bubbles inside your wax as it sets.  

How can I fix a sinkhole once it’s formed? 

So, you’ve followed all the above recommendations and a sinkhole still occurred? That’s ok, it happens. There are a few ways to fix a sinkhole once they’ve formed: 

1. If you’re working with a hard wax that you know is prone to sinkholes from your testing phase, pour to just below your ideal fill then once the wax has begun to set, poke a couple of relief holes around your wick (a wooden BBQ skewer is perfect for this step). This will help any trapped air escape and allow melted wax to fill any sinkholes that have formed within the setting wax. However, now that you’ve created holes, you’ll need to do a second pour to fill your relief holes. We recommend making sure you have some extra wax from your initial pour that you can re-melt and pour to fill the relief holes and top off your wax to your ideal fill.
2. If you’re working with a softer wax and not concerned about sinkholes inside your candle but your candle’s top is not as even as you would like or the wax has pulled away from the side of the vessel, then hit the top/side with a heat gun or hair dryer to re-melt the wax in that area and create a more even surface.  

We hope these tips and tricks are helpful for you on your candle making journey. Have questions? Send us an email info@creatorsjourney.ca or reach out to us on FB/Instagram @shopcreatorsjourney.

Written by Creators Journey