Vegetable shortening (Crisco) is partially hydrogenated and is a firmer semi-solid. To make a long story short, the more it's hydrogenated, the harder the consistency is.Īs an example, soybean oil is not hydrogenated and is liquid. Hydrogenated vegetable oils have some of their double-bonds saturated with hydrogen, which creates tristearines, hard and wax-like. Because of this and in contrast to paraffin, these oils do not expand (or they almost do not) when heated. They have carbon-carbon double-bonds as well as oxygen atoms that allow them to interact with one another thanks to an hydrogen bond. On the other hand, vegetable oils are acids with a high molecular weight (fatty acids). This is exactly what happens in your candles). Hot, they extend their arms horizontally, sideways and push each other away cold, back to their initial position. Following the same principle, when paraffin cools off, this energy is lost and a contraction occurs (picture this: a row of people standing side by side, arms against their bodies, shoulder against shoulder. When paraffin is heated, the molecules start vibrating because of the thermal energy, causing an expansion. However, a teaspoon of chemistry is needed to understand how it all works:Īs explained in the article about paraffin waxes, paraffin is made mostly of long-chain saturated hydrocarbons that don't interact with one another. The good news is you don't need a particle accelerator or a master degree in molecular chemistry ! 3) modify the chemical structure of the wax in such a way that it will shrink less when it cools It's actually a nice effect that can be intentionally created by placing the container in the fridge during thirty minutes before pouring but if you want to avoid it, you should heat the container in a warm oven ( 176☏) during ten minutes before you pour (or, alternatively, heat it with a blow of your heatgun)Īs your experience grows, you will know when the time has come to pour without the help of a thermometer. If the container is cold as well, when the wax touches the inner walls of the container, it will solidify instantly and create what is called jump lines (light colored horizontal lines).
So try and pour as slowly and from as low as possible, tilting the container whenever possible (like you do when you pour a beer and want to avoid the formation of foam) at this temperature, the wax is rather thick and any air bubbles that may form when you pour won't be able (because of the viscosity of the wax) to reach the surface and burst.And it is also the best time to pour the wax into the container. This is an indication that it won't take long before the wax returns to its solid state.
#IGI 4627 SKIN#
When you watch paraffin cool off in a pouring jug (I know, I have exciting hobbies !), you will notice that when the wax reaches its congealing point (the temperature at which it starts returning to a solid state), a thin skin starts to form at the surface, starting from the sides of the jug. If you have access to a low melting point paraffin, use it instead of classic paraffin, it will give you a head start.Īllow the wax to cool off as much as possible before you pour You see where I'm heading here : a wax with a melting point of 124☏ doesn't have to "come such a long way" when it returns to room temperature and will be less likely to develop a shrink well or pull off from the sides of the container. Regular, drugstore-grade paraffin has an average melting point of 139☏ The difference between the melting temperature and room temperature is rather large and will probably trigger a strong contraction of the wax (think of the shrink well that appears when you make a pillar candle).Ĭandle wax manufacturers offer a large range of waxes with different melting points for all sorts of applications (see for instance the pages about candlemaking waxes on the IGI Wax website) including a range of specially formulated container waxes with a relatively low melting point (usually between 122☏ and 131☏) Let us see what our options are: 1) use a wax formula with the lowest possible melting point Make sure that the temperature at which you pour the wax into the container is as close as possible to the room temperature.