Candles

It may seem like I write a lot about light, and I want to assure you that it's not because I'm afraid of the dark. I actually enjoy nights better than I do days, and I have even been deep enough underground to have experienced true dark. I just like to be able to see where I'm walking and be able to pick things up when I drop them.

Candle Facts

• Candles have been around for a long time. Only oil/tallow lamps and campfires are older sources of light, and candles store and ship better than either of them. 
• Candles have a very long shelf-life (decades) if stored below their melting point. 
• The basic measure of light is the candela or candle-power, because candles are easy to standardize and mass produce. 
• Candles are like any other flame-based light source in that they can present a fire hazard. Keep children and the child-like away from anything that burns, unless you want to hear a lot of screaming. Burns are one of the most painful and slow healing injuries a person can suffer.

Making candles is simple: it takes nothing more than a wick, wax, and a way to melt the wax. Molds are nice if you want large or ornamental candles or if you are mass producing them, but the tried and true method of repeatedly dipping a length of wick into a container of molten wax and letting it cool between layers still works. I'll cover the three parts in order.

Wick

The wick is the string-like thing on a candle that you light. The wick isn't what burns to produce light, but is instead a conductor for the molten wax produced by the heat of the flame. The wax flows up through the wick under capillary action to the area of flame, where it is vaporized and ignited, creating a flame and light.

Wicks are more than just a piece of string. They are made of cotton, and are woven or braided in a specific method to create the necessary “open” weave that will allow capillary flow of the wax. A lot of the better quality wicking will be woven flat to cause the burnt portion to curl away from the flame. This makes for a cleaner burn by keeping the burnt area out of the flame, where it would disrupt the air and wax flow.

Most wicks are treated with salt or borax to make them more fire retardant. In a pinch, you can use plain cotton string, but avoid anything synthetic.

Wax

There are a few different types of wax. The oldest is Beeswax, taken from a beehive when the honey is harvested, followed by Spemaceti (whale oil), and then paraffin (petroleum) wax. Various trees and plants produce waxes, but not in quantities that are commercially usable. A fairly recent innovation is soy wax, made from soybeans. They each have their pros and cons.

Beeswax has a higher melting point than the other waxes, about 63 Celsius. It also burns with a pleasant odor due to the tiny bits of pollen and honey embedded in the wax. Beeswax is the most expensive of the common waxes due to the fact that honeybees are in limited supply.

Spermaceti melts at about 50 Celsius. Found in the heads of Sperm whales, this is almost impossible to obtain today. The whaling industry doesn't really exist any more, thanks to over-harvesting and changes in markets. Jojoba oil (pressed from the seeds of Jojoba trees) has been marketed as a direct replacement for Spermaceti, but I haven't seen it used much.

Paraffin wax is a byproduct of diesel fuel production. If you've ever worked around a diesel engine in the winter and had the fuel “gel”, that is the leftover paraffin solidifying in the fuel. It starts to melt at about 37 Celsius when pure. Paraffin is cheap and is the most common wax used in free-standing candles today. Food grade paraffin is also useful for sealing Ball jars full of preserves when you run out of lids and don't need a vacuum seal -- I've seen it used mainly on jams and jellies.

Soy wax is made by treating soybean oil with hydrogen under high pressure and temperature, usually with the aid of a catalyst. Hydrogenated soybean oil may even show up in the ingredients of some of your food. Soy wax has a wide range of melting points, depending on the type of treatment and amount of additives it has had added to it, from about 49 to 80 Celsius. Because soy wax melts at temperatures commonly found in homes or storage, most candles made with it are “container” candles -- glass or metal containers filled with wax that have one or more wicks in them, like tea lights or devotional candles. If you can move the wax at room temperature with your fingertip, it's probably made of soy. Soy wax is cheap, and is as easy to find as paraffin at most hobby/craft stores.

Other vegetable waxes include Palm (from Palm oil), Lanolin (from sheep's wool), and Montan wax (extracted from soft coal). These are not normally found in candles, but have other commercial uses.

Heat Source

Since all common waxes melt below the boiling point of water, a steam bath or double boiler is the normal way to melt wax. Never try to melt wax over an open flame. Using an open flame gives you little to no control over the temperature of the wax, and also presents an ignition source for any fumes or vapors produced by overheating it. Dumping water on burning wax is a very bad thing, as it will only spread the fire and usually causes a huge fireball in the process.

A double boiler is nothing more than a large pot of boiling water with a smaller pot floating in it. Bring the water to a boil, turn off the heat and place the smaller pot in the water. Dump your wax into the smaller pot and let it melt. Once melted, the wax can be poured into molds or you can start dipping wicks into it to make your candles.

If you don't have a double boiler and still want to make candles, heat the wax up until you can roll or press it out into a thin (1/8th inch thick) sheet. Lay a piece of wick on one edge and roll the wax into a cylinder around the wick.

For prepping purposes, there's no real need to get into the various additives that you can put into a candle. Color and fragrance are way down the list of priorities compared to light.