A personal study of reproducing a Tudor verdigris compound for arrow protection
There are quite a few “recipes” available both online and in books for a medieval verdigris compound. Most are very similar, but often vague due to the lack of any real documentation from the period – wax, oils, resins and the powdered copper acetate scraped from sheets of copper suspended over vinegar in various ratios.
Mr Jeremy Spencer and Mr Alistair Aston of Warbow Wales have been doing extensive research into the verdigris mixtures along with in-depth analysis of the Mary Rose and Westminster Abbey arrows themselves for many years now. It’s the recipes and information that they have provided that forms the basis of most people’s reproductions of these items. Specifically, a recipe posted on their website (http://warbowwales.com) was the starting point for myself and many others in making a suitable verdigris compound.
In trying as many mixtures as I could find a common problem occurred throughout – the composition was too thin and the drying time of the mixture was far too long. With all the recipes, once mixed and applied, the compound behaved like a varnish. It was a brush-able liquid that took a very long time to dry, often up to 2 weeks. This seemed impractical as it meant that making arrows in large numbers would become a logistical nightmare, due to storage issues.
It was at this point that I got in contact with Mr Chris Dawson, who had been making a successful verdigris compound for some years. During discussions with Mr Dawson I was able to refine the recipe slightly. The ingredients were beeswax, verdigris powder and a form of artist’s varnish made of natural pine gum turpentine and resin in the form of pine tree sap or Dammar resin. This provided an excellent verdigris-infused varnish which could be brushed over the bindings. However, it still didn’t appear identical to the original arrows that I was looking at. They appeared to show a
consistent layer of solid coating with witness marks of both fletching and binding. This didn’t seem like a varnish painted over the bindings.
I returned to the recipe originally supplied by Warbow Wales, and began changing the proportions of the mixture drastically, to see if extremes would provide an answer. Adding far more pine resin gave the mixture a beautiful glassy finish but was almost impossible to apply as it cooled into a brittle compound immediately. Adding more oils and turpentine simply made it more liquid and far too slow-drying, so I was left with adding more wax. Previously, I had believed that the addition of too much wax was preventing the compound from setting hard enough, but when adding three times the amount I was using and removing most of the oils and turpentine, I was able to develop a mixture that was a thin liquid when hot, easily brushable and hardened within a few seconds to a resilient, hard and waxy compound. This wasn’t affected by heat or accidental knocks and would provide a solid protective layer over the bindings for storage and transport.
The recipe was as follows:
45g of beeswax
25g of pine resin
5g of natural pine gum turpentine
Enough verdigris powder to colour the mixture
Even up to this point, I was still approaching the compound as a liquid applied over the bindings, once the fletchings were glued into place. This is still the most commonly accepted method but wasn’t giving me the same results I could see in photographs of the original arrows and with the quick-drying compound very difficult to do neatly.
Simultaneous experiments conducted by Mr Guido Droste in Germany utilised a similar recipe to my own but applied prior to fletching. Being slow-drying the mixture allowed Mr Droste to attach his fletchings and then bind into place over the compound. The shaftment is then gently warmed and the compound melts just enough to blend the bindings and compound together into one solid protective base. With a quick-drying formula like my own, this is still achievable simply by holding the feathers in place with one hand while binding with the other. A quick drying compound also allows many arrow shafts to be prepared at once, which can be stored together with no problems. These can then be fletched and bound at a later time.
This method bears a remarkable similarity with earlier arrow manufacture – for example those found in Nydam, Denmark dating to 200 – 400 AD. These arrows have a thick black tar-based compound applied directly to the shaft, and very clear impressions of both fletching and binding can be seen in the compound. The Mary Rose arrows of 1545 are much more refined, and the compound is cleaner, thinner and wax or resin-based as compared to tar or pitch-based but the methodology remains the same.
It could be argued that gluing the fletching first, then binding followed by the compound would give the same witness marks, but the fact that compound can be seen beneath the impressions of the quill base in both the Nydam and the Mary Rose arrows makes this impossible. The compound must have been applied first, and the fletching bound down into it.
Weapons Of Warre by the Mary Rose Trust states that “previous analysis of [the compound] by gas chromatography and gas chromatography/mass spectrometry had revealed the presence of beeswax and a series of triacylglycerides, thought likely to derive from animal fat.” These could have been from animal hide glue, used to secure the fletchings to the shaft. However, if the fletchings are applied directly to the compound, then there is some form of animal triacylglycerides unaccounted for, if hide glue to secure the fletchings is unnecessary.
It was at this point that Mr Glennan Carnie suggested the use of tallow in the mixture. Tallow would have been cheaper than beeswax, and combining the two together creates a hard block of wax at a lower cost - it also contains animal triacylglycerides. Tallow has been suggested both in Weapons of Warre in the form of a tallow/wax mixture applied in layers and as a separate element of the mixture on various websites but not combined with wax as a base to which resin and other ingredients are then added.
Reproducing the compound
Below are two photographs – one of an original Mary Rose arrow taken by myself, and the other of my reproduction. It’s important to note the age and preservation of the original, and the fact that the bindings and feathers were pulled away from the compound on the reproduction, as compared to naturally disintegrating. There is also no copper acetate in the reproduction.
Below is an image of the same compound with copper acetate added into it as well. Less copper results in a lighter or less intense green colour.
In summary, it’s my opinion that most verdigris compound recipes have been created based on the theory that it is applied after the fletching and binding process and as such is often too thin or too slow-drying. This doesn’t conform to the physical evidence, and a waxy, firm compound applied at the start of the construction is the only method that perfectly replicates what we can see in extant finds. If this compound is quick-drying then many thousands of arrow shafts can be prepared with little time and effort, stockpiled in large quantities and fletched and bound when required. They can also be completed start to finish in quick succession.
In modern archery, the fletchings of arrows can be attached using numerous high-strength adhesives such as cyanoacrylate glues (superglue) or fletching tape and the need for binding them in place is removed. In the Middle Ages however, fletchings were attached either by wax or glue made from natural components and as such were likely to fall off if the wax/glue was heated, moistened or eaten by insects. This meant that binding was applied to secure the fletchings.
Period artwork shows this binding in very few occasions, yet the extant examples of arrows we have seen all show definitive wrapping of silk or very fine linen. Heath Hammond of the American Warbow Society has put forward the possibility that the full bindings were used only for arrows destined for storage or long distance transport, while arrows constructed for immediate use were simply glued and possibly bound at the head and tail of the fletching.
Those arrows destined for storage needed protecting further from the damages caused by bacteria and insects which would eventually remove the glues and bindings altogether. This was achieved using a waxy but solid compound applied around the bindings.
In most period depictions of this compound, the colour is usually striking – a dark, rich green. The green colouration comes from copper acetate or “verdigris” forming as a result of the corrosion of copper metal when exposed to acid over a period of time. Not only is it a striking pigment, but the copper is also poisonous creating a fungicide and insecticide when added to a mixture.
This can be seen very clearly on the remaining arrows discovered aboard the Mary Rose.
Fig. 1: The witness marks in the Mary Rose arrows, showing the compound underneath the quill base area, especially in the arrow third from bottom (Photographer: Bob Comlay)
Fig 2: The same witness marks in the Nydam arrows (Photographer: John Lee)
To use this compound, first the ingredients are melted together in a steel container over a flame. Once liquid, they can be brushed directly onto the arrow shaft or the shaft can be dipped into a long narrow tube holding the liquid. If the mixture is made up correctly, it should set almost instantly into a firm wax. At this early stage it won’t have fully hardened, so fletchings could now be pressed into the compound to hold them in place while binding. Alternatively, the compound can be left to cool and harden completely and then the feathers can be bound down into it, holding them in place with one hand and winding the silk through them with the other. The bindings will sit on top of the compound if left like this, but gentle heat from a flame will cause the compound to become liquid again, flowing over the bindings and encasing them. When fully cool the compound is almost plastic in its durability and completely protects the bindings from ripping or coming loose.
October 1st 2016
Fig 1: Photograph taken by Bob Comlay. Retrieved from <https://www.flickr.com/photos/bokononist/15213836305>
Fig 2: Photograph taken by John Lee, cropped. Danish copyright license <https://creativecommons.org/licenses/by-sa/2.5/dk/legalcode>