The candle was first manufactured thousands of years ago, using materials from livestock and insects. However, today most candles are made from paraffin wax. Unlike many of mankind’s greatest inventions which have become obsolete or extinct with time, the candle has never quite gone out of style. Although, they are no longer one of the sole sources of indoor illumination – not since the invention of the light bulb in the 1800s – candles continue to hold a special place in our hearts and in society. However, the knowledge of how to take proper care of them appears to be becoming extinct.
AIR BUBLES AND THE FINE ART OF CANDLE MAKING
Candle-making is a fine art that has existed for hundreds and thousands of years. It has persisted since earlier times, candles were one of the few light sources available to man ad candles were made from boiled down fat (tallow) from cattle and other livestock, as well as other animals and insects. During those times, candle-makers – also known as chandlers – were renowned for their skill and talent. As a matter of fact, the art of candle-making was so important back then that it became a guild craft, and chandlers would go from house to house in order to get commissioned to make candles for each household, using fat which had been set aside in their kitchens for that purpose (i.e. for the express purpose of candle-making). As a result, many of the candles produced during those times were of very high quality. Not only did earlier chandlers spend several months – and even years – learning their craft, they also had a market that knew how to tell the quality of their products. However, with the invention of electricity in the mid 18th century, the nature of demand for candles was changed forever. Arguably because of this, the general interest in the art of candle-making began to experience a massive decline which has now resulted in a much higher occurrence of defects in candles such as the occurrence of air bubbles on the side of candles or/and within them. In recent decades, there has been a noticeable rise in the demand for candles, particularly scented candles – however, despite this growing interest, many chandlers of today still run into a lot of defects which were not very common back when candles were one of the greatest sources of indoor illumination. The occurrence of air bubbles in candles is one of those lingering defects.
WHY DO AIR BUBBLES APPEAR IN CANDLES?
Air bubbles are defects or flaws in candles that arise as a result of many reasons, the greatest of which include:
- Pouring hot candle wax into cold moulds
Temperature is one of the most important things to watch out for in candle-making. The candle itself is something that is sensitive to temperature, which is why the wax always melts when the wick is lit, only to solidify later when cooled. And so, temperature should be taken into account not only during the preparation of candle wax but while pouring the wax into moulds. Pouring hot candle wax at about 85 ºC into cold moulds about 25 ºC or lower creates a temperature gradient that needs to be overcome as the candle begins to set. This results in a situation where the outside of the candle solidifies at a much faster rate than the inner parts, in some places and eventually bubbles are usually formed on the sides of the candle or inside it (or both on the sides and inside the candle).
- Pouring cold candle wax into hot moulds
Pouring cold candle wax into hot moulds is also another situation which can result in the occurrence of air bubbles on the sides of candles and within in. Here as well, a temperature gradient is formed between the candle wax and the mould and this will cause portions of the candle to solidify faster than others. Thus this uneven cooling can result in the presence of air bubbles on the sides of the candle and within it.
One unique thing about cold candle wax – or wax that is at a much cooler temperature than it needs to be during the process of candle-making – is that solid pieces or portions of wax already exist within it, thus affecting its pouring ability. This would then result in air bubbles and air pockets on the sides of the formed candles, as well as its interior.
- Not taking enough care when pouring candles into moulds
Asides temperature, another thing that can increase the risk of air bubbles flaw in candle- making is the speed and method by which the hot wax is poured into the mould. Care should be taken when pouring hot wax into moulds in order to prevent the risk of air mixing with the wax. Therefore, the candle-wax should not be poured too slowly or too fast, as this can allow air bubbles to form on the sides of the candle and within it.
HOW TO PREVENT THE OCCURRENCE OF AIR BUBBLES IN CANDLES
Air bubbles are very dangerous because they affect the efficiency of candle burning. When spaces which should contain candle wax are filled instead with air bubbles, the candle tends to burn down faster. Also the presence of air bubbles on the sides and interior of a candle is often indicative of much larger air pockets which may lead to the explosion of candle wax, and this may cause an accident. Therefore, it is very important for air bubbles to be prevented when making candles.
To prevent the air bubbles flaw in candle- making, hot candle wax should not be poured into hot moulds and cold candle wax should not be poured into hot moulds. Also, cold candle wax should not be poured into cold moulds either. Instead, the temperatures of the candle wax and that of the mold should be ideal to ensure the proper cooling and setting of candle-wax. This is very important as many of the most common reasons for the appearance of air bubbles in candles involve the common thread of being temperature related. Also, the speed at which candle wax is poured into the mould should be regulated (i.e. it must not be too fast or too slow) in order to prevent air bubbles from forming on the sides of the candles or within it.