Gel wax is different from paraffin wax in a number of ways. Gel wax is a combination of mineral oil and polymer resin. It has a slow melt rate and a long burn time making it good value for the money. Gel wax is translucent and has the consistency of a firm 'Jelly'. Gel wax doesn't so much 'melt' as become thinner and runnier, allowing it to be poured.
A popular wax, the clarity of the set wax means pretty embedded decorations can be used. This wax is often found in candles sold in souvenir shops. The gel is dyed a light shade of blue, and sand and shells are often added to make a novelty under-water scene. Other novelty candles using gel wax are filled with slices of dried fruits, small glass ornaments, glitter or anything that won't melt at a temperature lower than the wax.
Gel wax is used in containers, it doesn't have the rigidity to stand upright on its own. If you want to colour gel wax, it's better to use a liquid dye. Paraffin based dye chips or pellets will cause the gel wax to go 'cloudy' and it's difficult to get an even distribution of colour.
Gel wax has a higher melt point than paraffin waxes and is melted in a pot over direct heat, rather than using a double boiler. Gel wax does have a tendency to bubble, lovely is you're making a sea scene, not so good if you're not. To avoid bubbles, heat to a temperature in excess of 230 F, but don't exceed 260 F - the gel wax could ignite at this temperature.
Gel wax is available in 3 different densities, each one displays different characteristics.
LOW DENSITY - Low density Gel wax is the cheapest, and the easiest to melt as it has a lowest melt-point. It is however not firm enough to support embeds held in suspension, and better kept for candles with decorations that rest on the bottom of the candle. Low density gel wax will only hold fragrance at about 3%, so if you prefer a quite highly fragranced candle, use a higher density wax.
MEDIUM DENSITY - Still relatively east to melt and pour, but slightly thicker than low density, so it will support light-weight embeds such as beads, small flowers, glitters etc. Heavy items such as metal charms, glass embeds, larger beads etc will sink to the bottom.
HIGH DENSITY - This gel wax needs to be melted at a high temperature, but is firm enough to hold embeds in suspension. Wonderful if you are creating 3D scenes. It will hold candle scent up to 5 or 6% allowing you to create more strongly fragranced candles.
Wick for Gel Wax
A rigid, zinc core or paper core wick is favoured for gel wax. This type of wick has the rigidity to stand upright in the wax, keeping the burn pool central. gel wax burns more slowly than paraffin wax, so as a general rule of thumb, it is advisable to go up a wick size from the one you would use (or is recommended) for the same size container using paraffin wax. It's best to prime the wick with gel wax, not buy ready assembled wicks that have been primed with paraffin wax. The gel wax tends to be poured at a higher temperature than paraffin, and the paraffin wax around the primed assembly will melt and make the gel wax go 'cloudy'.
Scenting Gel Wax
Not all scents used in paraffin and vegetable waxes are suitable for gel wax. The scents recommended for gel wax are called 'non polar' and have a flash point in excess of 170F.
Not using the right scent for gel wax can be hazardous. Unscented Gel wax has a burn pool temperature of approx 270 F, this is well below the general flashpoint of 440 F for the gel wax itself. However, adding scent lowers the flashpoint of gel wax, bringing it much closer to the burn pool temperature. Polar fragrances used in standard wax candles can drop the flash point temperature alarmingly low, perhaps so low it can cause the gel wax to ignite, so avoid these fragrances at all costs.