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Flash Points Explained
As a candle maker, beginner or otherwise, you may have come across the term ‘Flash Point’. This can be confusing to understand, but we’ve broken down the key factors to help you understand the science behind making candles!
What is a Flash Point?
Many fluids give off vapors, including fragrance oils, which is the point in time when the liquid starts turning into a gas.
Generally speaking, the warmer a fluid is the more it wants to “release” vapors to the atmosphere, but cooler liquids hold their vapors much better.
The flash point is the temperature where a fluid (any fluid) gives off enough vapor that an open flame could ignite it. This doesn’t have to be a continuous more ‘flammable fire’ but a brief flash of light, hence the name flash point.
The only thing that can ignite the vapor is a true ignition source, not just heat.
For example, submerging a fluid that is heated to its flash point temperature in super hot wax (as is the case with adding fragrance oil to wax), it won’t ignite the oil, but lighting a match (an open flame) over it will.
The Flash Point that you will find on your fragrances SDS sheet is an indication of the temperature at which you fragrance will ignite to an open flame and is therefore not something that needs to be overly considered when mixing with wax.
What a Flash Point Is Not
A fragrances flash point is merely there to state at which point, when ignited by an open flame, it will ignite. This means that the flash point is not to be confused with fragrances being ‘burned off’ when added to wax at high temperatures. Simply warming a fragrance oil to the flash point doesn’t create mass-evaporation of the oil.
In short, unless part of your process involves lighting a match over the surface of the fragrance, you won’t lose any scent from those temperatures.
Fragrance oils will only ‘burn off’ at the fragrances specific boiling point. Fragrance oils lose scent through evaporation. The critical temperature associated with volatility of a fragrance oil is called the boiling point. When fluids reach their boiling point, they evaporate. If the fragrance is raised to the boiling point, then mass-evaporation would occur and a lot of scent would leave the fluid, however, this only applies to the fragrance oil by itself, when introduced to wax, the effective properties of the blend aren’t those of wax OR of fragrance oil – the properties are a mixture of both.
In general it’s best not to worry about your fragrances igniting or loosing their throw when making candles, as long as you are adding your fragrance at the correct temperature and in the correct quantities.
You can read more about adding fragrance oil to your candles here.
Gel candles
Our Gel Wax will hold up to 6% fragrance oil. But it's important to note that not all scents are suitable. The scents recommended for this wax are called 'non polar' and have a flash point in excess of 77°C. Not using the right scent for gel wax can be hazardous. Unscented Gel wax has a burn pool temperature of 130°C, this is well below the general flash point of 227°C. However, adding fragrance lowers the flash point of the wax, potentially low enough to cause the wax to ignite, so avoid these fragrances, and be sure to test your gel wax candles in a safe controlled environment.
To find out which of our fragrances and essential oils are suitable for use in gel wax view our table here!
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