When making candles, it is really important to conduct candle burn tests to ensure that the candle meets safety and performance standards.
A candle burn test is one that can last as long as a few weeks, depending on your candle, as each candle in the test will need to be burnt in until the candle is either used up or fails. As candles are combustible, it is important that your candle can fill a room with aroma, without sacrificing safety.
Candle makers typically use this test to prove to customers that their candles are safe, with an appropriate hot throw.
Regardless of whether you will be selling your candles, a burn test will provide you with an idea on how well designed your candles are, helping you optimise its performance while maintaining safety standards.
If you are looking to conduct a simple candle burn test, read on to find out how.
Purpose of a simple candle burn test
As mentioned, this candle burn test can help ensure that your candle meets the necessary safety and performance standards.
Another purpose of this candle burn test is to tell if your candle needs a larger, smaller or different wick.
As fragrances and waxes have different thickness and viscosity, you will need to use a proper wick for your candle to perform safely. for example, thicker fragrances and high viscosity waxes will need a thicker wick, as compared to thinner fragrances and waxes.
What to do before burn testing
The most important part before conducting a candle burn test is to ensure that your candles are made and substantially cured. Waiting for your candle to cure for the recommended amount time is a necessary step before starting.
As wax changes dramatically as it hardens, starting your candle burn test before it is properly cured can result in a misleading test result. Remember that patience is needed, especially when waiting for your candle to cure.
If you intend to test multiple candles at once, ensure that they are clearly labelled.
ASTM standard burn test
Trim the wick to 1/4 inch.
Place your candles on a flat heat resistant surface. If you are testing multiple candles, keep each candle 3-6 inches apart.
This area should be clearly visible as your candles should not be left unattended while lit, especially so when testing new wicks.
Light your candles and take note of the time.
After 2 hours, observe the candles and take note of any noticeable details, such as the melt pool and wick appearance.
After 4 hours, observe the candles once again, taking note of noticeable details, before blowing out the flame.
Allow your candles to cool for at least 5 hours and repeat until the candle is completely burned.
Burn test results
By observing the results of your test, you will be able to identify if your candle needs a bigger or smaller wick.
If the wick is too big or too hot, you will notice:
- Your container temperature exceeding 140F
- 5mm or greater carbon balls
- Excessive soot
- Flame greater than 3”
- Large melt pool
While if the wick is too small, you will notice:
- Candle tunnelling
- Flame that extinguishes before the end of the candle
- Wax on the edges after your candle finishes
Now that you have an idea on how to conduct your own candle burn test, go forth and experiment!