Tunneling is a common problem in candle making. We would look at, in this article, the causes of tunneling and how to prevent and fix candle tunneling. With candle tunneling, prevention is the best and if your candles have been having that problem, you are just about to know what to do to stop it.
The wax and wick are the most essential element in candle making. Both work together to ensure a clean burn. The candle wax is the ‘fuel’ of the flame and as the wick burns down, the candle wax gradually depletes. Under normal circumstances, this depletion should take place evenly across the surface of the candle. When it does not, it is called candle tunneling.
If tunneling occurs, instead of the wax to melt down evenly, there is just a hole in the wax through which the wick burns. If a candle tunnels, you would notice a round patch of wax around the edge of the container that remains dry and does not melt as the center does. Container is mentioned because tunneling is noticeable in container candles. Tunneling is so common in candle burning that some people think that is just how some candles burn. But, no, that is not how. Candle tunneling is a problem and a sign that you have done something wrong in making your candles (if homemade) or in burning them.
Some Effects of Candle Tunneling
As mentioned, the visible sign of candle tunneling is that the wax would not melt all the way to the edges of the container. But what exactly does this cause?
• It becomes hard to relight the candle when its flame goes off. This is harder with large container candles. And it happens because only a small hole is made through the center of the candle. As a result, once the wick has gone too far down, it will become difficult to get a lighter through the hole to relight the wick.
• Also, when a tunneling candle burns up to a certain point, the wax at the edge of the container collapses over the wick, drowning it. That means that candle has become useless, except for such use as is to leftover wax.
• The candle flame goes off when there is still a lot of unused wax that has not melted. Tunneling is wastage of wax. The wax around the edge of the container that does not melt is a waste.
• It is unsightly. Tunneling can render ugly the most beautiful of candles. Yes. Seriously, who likes a candle that burns with a hole at the middle? The flame burns within the candle and is not even seen unless looking at the candle from the top.
Causes of Candle Tunneling
Tunneling can be caused by either using the wrong wick for the candle or burning the candle the wrong way. Either way, tunneling shows something is wrong.
• Using the Wrong Candle Wick
Not using the right type or size of candle wick would lead to tunneling. It happens because the flame from the wick does not burn widely to the edges of the container. Most cases of tunneling are a result of a small wick being used for the large container. Size here is in terms of diameter.
• Burning the wrong way
When a candle is burned for only short periods at a time, it would not achieve a full melt pool and so tunneling can occur.
How to Prevent Candle Tunneling
You may have inferred ways to prevent tunneling from the sections above. But I will give you more details here.
• Use the right size of a candle wick.
The diameter of the container should determine how thick a candle wick should be. Using a small candle wick for a large container would cause tunneling.
• Short candle wicks.
Yes, candles wicks should be trimmed before the candle is burned. But an ideal level is a quarter to one half of an inch. Anything lower would result in tunneling. This is because the flame from the wick would not burn high enough to create a full melt pool. Actually, candle flame should not be too high, as that can cause new problems: smoking and appearance of black hair residue (soot). So it is better to stay within the ideal level. For larger containers, you may not trim the wick to the recommended level at first to get a full melt pool. But when you light the candle wick and notice that the flame is too high, turn it off immediately and trim it a little. Candle wicks are to be trimmed before each burn, not just the first burn.
• Double Wicking large candles.
Even by trimming your candles to the recommended level, you may still not get a full melt pool if you are using a larger container candle. To prevent tunneling in container candles, it is necessary to use two wicks for each candle. The wicks should be arranged in such a way that they are able to each cover half the container. That means there should be some form of distance between them. It pays to imagine your container divided into two, and having a wick in the center or each division. There is a different article devoted to double wicking your candles; you may want to check it out.
• Use of wrong wick type.
There are different types of wicks and different considerations to be made in choosing one. Apart from the size of the container, you also need to consider the type of wax being used before purchasing wicks. All wicks do not work with all types of wax. So using a type of wick that is not suited to the type of wax being used means that the candle would not burn well. And poor candle burn is also one of the causes of tunneling.
• The perfect first burn.
The first burn of the candle goes a long way in determine how the candle burns subsequently and how the wax depletes. You can prevent tunneling by making sure that at first, the candle is burned long enough to have a full melt pool. If the candle does not melt all the way on the first burn, subsequent burns would follow the pattern established and most likely cause tunneling.
• Longer burn periods.
I mentioned above that burning a candle for short periods of time can cause tunneling. So a good preventive measure would be to ket candles burn for longer periods before putting off the light. However, how long a candle should be burned at a time depends on the size of the container. It can take up to two, three hours or more to get a full melt pool. Here you can do a little experiment to know how long your candles need to be burned. So expect tunneling if you light your candles for thirty minutes, one hour periods. If you want that, then you may want to get another type of candle.
How to Fix Candle Tunneling
• Fixing a short wick problem.
If the cause of the tunneling is that the wick is too short, there are different solutions to it. Of course, you would not be able to lengthen the wick but you can manipulate the wax for better burn. First, if the wick is caught in melted wax, pick it up using tweezers so it can start straight. After that, dig the area around the wick a little. Do not dig too dip, else, you just worsened the issue. Better still, you can use a heat gun to melt the whole surface of the candle and remove the excess wax. This method is more efficient as you would get an even surface. When the wick extends out the wax at the normal height, you can now light the candle and let the wax melt evenly.
• Removing excess wax.
You can simply use a knife to remove the excess wax, that is, the ring of wax above the wick. Such excess wax can be used for something else; it can even be melted and used to make another candle. This method is not very effective as there is a probability that the candle would still tunnel again. Hence, the next method.
• ‘Resetting’ the wax.
We talk of ‘resetting’ wax because it has a ‘memory’. This is why the first burn is very important as I have stated above. Place the candle in a hurricane or a vase and let it burn for some hours until the top is all melted wax. Alternatively, you can wrap the candle with aluminium foil with the top opened. As the candle burns, heat flows round the candle, melting the excess wax. You may have to take out some liquid wax as it burns so that it would not drown the wick. This method is effective as it not only fixes the tunneling but it also makes it unlikely for the candle to tunnel again.
Note that most candle tunneling issues (especially relating to the wick) arise with homemade candles. This should not deter you from undertaking your own candle making project. Candle making is very interesting but one has to be careful to get perfect results. Just as a reminder: pay attention to the wick you use and how the candle is burned if you want to avoid tunneling issues.