How do I permanently soften beeswax to a Play-Doh-esque consistency?

Question

I recently read an academic article suggesting that ancient Mesopotamian scribes wrote cuneiform not just on clay tablets, but also on wax-covered writing boards. I haven't seen this discussed before, and I'd like to test how practical it really is, so I'm hoping to make my own replica writing board and try it out.

(The one in the picture is a Roman design from several centuries later, but the principle is the same.)

For the most part this seems straightforward enough. I'll need to make a pair of tablets with a hollow in the middle, hinge them together, and fill the two hollows with melted wax. When the wax solidifies, I'll have a writing board.

The part I'm stuck on, though, is how to give the wax the right consistency. For cuneiform writing, I need to be able to easily push a stylus down into the wax and leave an impression, then smooth out the wax to erase the marks again. (Cuneiform involves "stamping" the stylus into the clay rather than dragging it through.) But I also want to be able to fold up the tablet and carry it around without the wax losing its shape.

Play-Doh seems to be about the right consistency for this—it takes impressions very well, and I can open a container and set it upside down without the clay coming out. So my question is: is there a way to modify beeswax (or some other wax, but beeswax is the easiest for me to get) to have that sort of consistency? I've read that melting it with mineral oil prevents it from hardening fully, but I don't want a liquid, I want it soft but solid enough to hold a shape.

Answer 1

There is a variety of recipes out there (my notes and emphases):

• The more advanced one included mixing in a resin:

  Beeswax for [medieval?] writing tablets seems to have been mixed with resin, such as the terebinth resin added to medieval sealing wax.
  [..]
  I have been unable to obtain terebinth resin, but I have experimented with mastic resin. Terebinth is produced by the terebinth tree, Pistacia terebinthus and Pistacia palaestina. Mastic is produced by the mastic tree, Pistacia lentiscus. They are members of the same genus, and so closely related that Pistacia saportae is believed to be a hybrid between P. terebinthus and P. lentiscus.

  Mastic and dammar have similar properties when used as a varnish or to temper wax, but less dammar needs to be added to the beeswax for the same hardness, and mastic is much more expensive.

  I experimented with a mixture of mastic and beeswax, in the proportion of the above recipe. Mastic has a higher melting point than beeswax, so I melted it first [i]n a pan with a digital thermometer, and then mixed in beeswax. The result, as expected, was harder than untempered beeswax, with a higher melting point. It seemed somewhat softer than a typical recipe for contemporary encaustic medium which uses one part dammar resin to six parts beeswax, but a dammar based recipe could achieve similar hardness by adding more beeswax.

  Wax for wax tablets would probably use a higher proportion of beeswax than sealing wax. Artists' encaustic medium would serve well as sealing wax, but I believe from my experiments that three parts beeswax mixed with two parts encaustic medium would serve better for a writing tablet. This is based on my experiments with the Enkaustikos brand of wax medium.

  A well stocked art supply store can provide encaustic medium, either premixed with pigment or not. I mixed this with yellow refined beeswax.

• For a school project, someone just added a quarter of coconut oil to the beeswax, and that consistency seems fine as well:

  Melt three tablespoons of beeswax pellets, and one tablespoon of coconut oil, together in a bowl in simmering water, over a low heat [i.e. au bain-marie].

  

• A recipe here only adds carbon black pigment (or black wax crayons) to the otherwise unaltered beeswax:

  I recommend beeswax blackened with lampblack (powdered carbon). Beeswax can be obtained at any apiary, or wherever you can buy honey in quantity. Lampblack can be purchased from pigment suppliers. Alternatively, you can blacken the wax by melting a black wax crayon into it. Some manufacturers make crayons with plastic in them; if you are not sure what your crayon is made of, melt it separately. If it melts like wax, you're OK. [What follows are easy instructions for preparing and pouring the wax.]

  But, as pointed out here:

  In both Classical times and the Middle Ages and, moreover, in modern Europe, the wax layer of most wax boards was black. The reason for this is that in those times beeswax was normally mixed with charcoal or soot in order to improve the plasticity of the paste.

  However, legibility suffers from the dark wax, which was called "sad wax" (tristes cerae) by the Roman poet Martial :)

The difference between recipes is making me wonder if the consistency and writing quality depends on the type/quality of the beeswax one uses, depending partially, perhaps, on the amount of pollen it contains (different compositions are mentioned in paragraph 5.1 here, as well). On the other hand, different producers/writers/artists/craftspeople will have different preferences, and different environmental conditions will also have an impact.

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For historical accuracy, we have to delve deeper into analyses of the wax used on the tablets from the time cuneiform was being used (3000 BC - AD).

• Here is a webpage with some background information (I got that link through this page which also contains a lot of interesting background information):

  According to analyses performed in the 1950s in the British Museum laboratories, the wax layer of the Nimrud writing boards [ca. 721–705 BCE] consists of beeswax compounded with ca. 25% sulphide of arsenic (orpiment [As₂S₃]). The use of orpiment, a highly toxic substance, was apparently aimed at giving this luxurious showpiece the appearance of gold.

  Orpiment is still sold as a mineral, and ground as a pigment in specialized stores, and can easily be found online.

• From a page linked above, the authors of which came to a conclusion similar to the one you arrived at when it comes to using pure beeswax, mention how in order to get different types and colours of wax (such as green and red), a variety of substances were mixed in with the wax..

  including oils of various origin, resins and turpentine, dairy products, honey, ochre, charcoal, soot, verdigris, cinnabar, red lead (minium), azurite, and basic lead carbonate (white lead).

  The black wax was likely a cheap variety of writing wax.

  Yellow ochre is mentioned in an Akkadian source, perhaps as an ordinary alternative to the rare and expensive orpiment:

  Further evidence is found in cuneiform tablets from the Neo-Babylonian and Achaemenid periods (7th–6th century BCE), containing expenditure accounts related to the manufacture of wax boards. These texts not only mention wooden boards, but also regularly refer to beeswax and yellow ochre (Akkadian kalû) as the necessary raw materials, thus providing indirect evidence for the composition of the wax paste. One of these texts also mentions a certain quantity of sesame oil, yet its purpose is unclear.
  [..]
  In view of the fact that high quality ochre was readily available all over ancient Mesopotamia, it seems likely that yellow ochre was the standard additive to beeswax in Ancient Near Eastern wax boards, whereas charcoal may have been used in Greece and Rome, simply because it was the most widely available pigment and subsequently canonized as a standard ingredient.

  Apart from the colouring, the addition of pigments to the wax paste reduces the beeswax’ stickiness and increases its malleability. As far as ochre is concerned, two of the Neo-Babylonian cuneiform accounts mentioned above suggest a proportion of 6.6% and 10% of ochre in the wax paste, a quantity that is very close to the average amount of ochre present in the sample of wax boards analysed by Reinhard Büll. Our tests showed that the addition of ochre (or arsenic sulfide), up to an amount of ca. 40–50%, generally makes the paste softer than pure beeswax and reduces its stickiness, thus meeting the basic requirements for a writing board. The proportion of either of these ingredients may vary between ca. 5% and ca. 50%; pastes with more than 50% ochre become too granular and too hard, especially at low temperatures, so that the wedges can be impressed only with difficulty.

  As for physical factors weighing in on that experience:

  Writing cuneiform on a paste containing 50% ochre at minus 10 °C requires a lot of pressure, whereas a paste with only 7% ochre feels very soft when writing at a room temperature of 35 °C.

Yellow ochre is quite easily obtainable and cheap, historically accurate, non-toxic, and easy to work with, so using this pigment to change and improve the consistency of your recipe is likely your best option.