We all know what a wax feels like from experiences of warming Babybel rinds in our hands to model them it into tiny red sculptures, using Vaseline or beeswax to protect our chapped lips or hair wax to style our ‘do, or watching water bead on the waxed surface of an apple or surfboard.
But what does this motley crew of substances have in common?
At the Materials Library we have a particular soft spot (pun intended) for waxes, partly because this weird grouping of sticky, slippery and unctuous materials are actually quite different in terms of their chemistry and their origins in nature. Waxes can be animal, vegetable and mineral-derived, made by everything from otters and kale to beetles and bacteria. They can be found in the ground (ozokerite) or synthesised (paraffin wax), but they are held together by their shared behaviour and the history of how they’ve been used.
The origins of the word wax come from the Anglo-Saxon word for honeycomb, so fragrant yellow beeswax could be considered the original ‘reference wax’, and all other waxes are so-called because of their physical similarity to the glandular produce from a honeybee.
Young worker bees secrete beeswax from near their abdominal glands and chew it, mixing it with saliva, pollen, honey and propolis until it darkens and becomes a pliable and waterproof construction material. They use this to build honeycomb structures to store and protect honey and raise young bees. It is extracted by spinning the whole honeycomb in a centrifuge to separate the honey and wax, and it is then used for candle-making, cheese-wrapping, lipstick-making, furniture-polishing, as a shiny food additive (E901), and as an antibacterial and anti-inflammatory ointment to treat burns and wounds.
Other waxes derived from animal sources include pungent and claggy lanolin (extracted from sheep’s wool) and odourless spermaceti (oil from the head cavity of the sperm whale). Shellac wax is made by the lac beetle, a little scale beetle from South East Asia that exudes a chitinous mix of resin and wax as a protective cocoons for her eggs and the twigs she lays them on. We extract the wax from this beetle-made composite and use it as a polish for furniture and a coating for sweets like chewing gum and jelly beans.
Waxes do not all have the same chemical composition: they typically contain long-chain hydrocarbons, but these could be of any length, and could contain a variety of different functional groups, so could actually be chemically quite different. As you can see from handling our selection, waxes might be solid or liquid, brittle or malleable. Some are sticky, some are slimy, but all are brought together by shared behaviours that include: malleability, low melting point and a resistance to being dissolved in water.
Waxes are hydrophobic (resistant to being dissolved in water) and play a protective and antibacterial function as a result. In nature, this allows them to act as a protective coating: stopping water getting out, and stopping water and bacteria from getting in. This is as true in waxed lemons as it is in ducks: if you try to get either of them wet you will notice that water beads up and rolls off their surface, and as it does, it takes with it any lurking dirt, bacteria and mould spores. Humans use all sorts of lotions, potions and emollients, like Vaseline and lanolin, to create protective oily films on our skins to lock in moisture and support our skin barrier. We also use waxes like Renaissance wax to protect important heritage objects and artworks, bottle sealing wax to protect wine, plant grafting wax to protect the wounds of newly grafted fruit trees, and earwax to protect our inner ear from infection.
The protective and antimicrobial effects of beeswax were even understood by ancient Egyptians, who used beeswax in the mummification process (along with a bunch of other substances like pistachio resin and bitumen) to preserve corpses by removing liquid and supressing fungi, bacteria and odours.
Because it is biocompatible, wax has been used in and on the body for a very long time. There is some evidence from Slovenia to suggest that it was also used as an early dental filling around 6500 years because it is both suitable for use on the body and receptive to fine detail. In medicine, bone wax has been used to prevent excess bleeding during orthopaedic surgery, and lanolin has been used for medicine delivery because it is readily absorbed by the skin, transporting substances like nicotine, oestrogen and hydrocortisone along with it.
Wax’s similarity to human flesh has made it one of the best materials for mimicking human skin in theatrical prosthetics and waxwork models of famous people: our sample of Tussaud's casting wax is a special blend of paraffin wax, beeswax and sometimes sumac (Japan) wax. We even have a sample of artificial eye wax that is used by prosthetists to create a temporary model of the replacement eye that can be tested in the eye socket and easily adjusted to make it comfortable before a permanent glass or acrylic resin version is made.
Waxes are distinguished by their malleability and low melting point, which is why they are such a great material for drawing, sculpting (see our scopas modelling wax), and candle-making. Beeswax, carnauba and petroleum waxes are all used for the wax crayons that are responsible for the daily scribblings of children all over the world, as well as the work of artist Cy Twombly. You can feel by comparing our waxes that this malleability (how much they can be deformed by squashing) varies a lot, and this is to do with their molecular structure. Waxes have a crystalline molecular structure which is a lot like a metal’s: under a microscope both waxes and metals are made up of lots of tiny crystals, called grains, which are tessellated together in a pattern that looks a bit like crazy paving. When you squish a piece of wax you are forcing these tiny grains to stretch, bend, and slide past one another. When these crystals are smaller and more irregularly arranged they can more easily move past each other, and the wax is more flexible and malleable.
Different waxes also have a range of different melting points, and this relates to the length of their hydrocarbon chains and how much energy is needed to break them down. The softest waxes, like coconut wax, start to melt over 40°C, whereas some synthetic waxes need to be over 100°C to soften. Those waxes that melt with the heat of your hand or under friction and are polishable under pressure are great as car and furniture polishes. Malleable and meltable waxes also gave us one our most ancient metalworking techniques: they have been used since the Early Bronze Age (late 3rd millenium BC) for lost wax casting. Take a look at our bronze casting wax and luted crucible for more about lost wax casting.
As we explored in our Festival of Stuff candle-making activity, wax is also flammable, and as a result its most prominent use for centuries has been for making candles. Waxes are generally not flammable in their solid form, but when the wax melts and vaporises it burns, which is why you need a wick to heat the wax and then ‘wick’ it up so it can burn. Waxes are also suitable for candle making because they are great at taking on colour, as you can see from our rainbow of beeswax tablets, and scent, as you can smell from our heady damask and tuberose perfume ingredients produced by wax enfleurage.
And finally, waxes are used to lubricate everything from our saws, to drawer runners, leather workers needles and threads, and suppositories and pessaries. Our bullet lubricant wax is even used to reduce friction between the bullet and gun barrel.
Waxes can be combined into endless application-specific formulations: there are different waxes for cricket bats, cricket balls, polo sticks, darts, surfboards, snowboards, skis, water skis and ice hockey pucks, for example. Specialist kinds of wax are linked to specific parts of our bodies like earwax (you will be pleased to hear we don’t have any of this in the Materials Library…yet!) and bikini wax. There are specific blends of wax for particular professions, with various types of jeweller’s wax, shoemaker’s wax and even magicians’ wax that is used to secretly secure props, anchor invisible threads for levitation, and manipulate playing cards.
Is there anything this wonderful family of materials can’t do?!
