Flames commonly burn with a yellow and orange colour, but the hues are not usually clearly defined or vivid. If you want to create an interesting display when lighting your candles, create coloured wicks that allow your candles to burn bright in all the colours of the rainbow. You can use these wicks to produce simple, homemade, coloured-flame candles for use at parties, on cakes or simply to add a nice touch of decoration.
Choose the chemical for the colour you want for the flames. Strontium chloride burns red; calcium carbonate burns orange; sodium chloride burns yellow; boric acid burns green; copper chloride burns blue; potassium chloride burns purple; and magnesium sulphate burns white.
Fill a small bowl with your chosen chemical, and soak the candle wicks in the bowl. The wicks don't need to be dripping wet, but the chemicals must be thoroughly soaked into the entire length.
Thread the soaked wicks into the candle mould and plug the open holes at the bottom with clay. The clay will stop the melted wax from leaking out of the bottom of the mould.
Fit the double boiler with a confectionery or cook's thermometer and pour the paraffin wax into the top of the boiler. Heat the wax until it reaches 54.4C.
Pour the melted wax into the mould around the wicks and let the mould rest for 12 hours at room temperature. Move the mould to the refrigerator for another 12 hours before unmoulding.
You can use the same colour wax as the colour the wick will burn to keep track of your coloured candles.
Do not leave burning candles unattended.