note, this is my documentation from 2015. Over the years, these have held up quite well although they have softened somewhat. Overall I would consider this experiment to be a success, but not the final solution.
A 14th Century Leather Rerebrace
Kingdom Arts and Sciences 2015
Project Description:
To create a pair of hardened leather rerebraces, suitable for SCA combat, based on an extant piece in the British Museum (item 1865,0701.1665). The piece will need to be able to withstand blunt impact, wet conditions, and general wear and tear.
Extant Piece:
The rerebrace in the British Museum (see cover page) is made of leather, tooled with scrollwork inhabited with grotesques. The grounding consists of fine lines of dots, approximately 36 to the inch, while the outlines are made with a blunt liner. The entire piece measures 287mm (11.3″) in length, which based on anthropomorphic data would indicate that it was made for a man at least 6′ tall. The piece is lined with a second lighter piece of leather, possibly as padding, or perhaps as reinforcing for the extant tear. The remains of three straps run through slits in the leather, one on the long outer edge and two on the inner edge. The object description does not provide the thickness of the leather.
Museum number 1856,0701.1665
Description Upper cannon of a right vambrace (rerebrace) of moulded leather. Originally tubular, it has been flattened into its current rounded Tshape. It has a pair of holes at the top for points, a slot with the remains of a leather strap at the centre of the outside edge, and slots for two more at the centre of the inside edge, one containing a strap fragment, where it was originally strapped round the arm. Inside is a separate leather lining, of softer leather, with a repaired cut. The exterior is tooled, stamped, incised and modelled with diaper design of foliage inhabited by birds and mythical twolegged beasts, and a plain border. The upper rear border has been cut off.
Date 14thC
Dimensions: Length: 287 millimetres, Width: 245 millimetres
Past Research:
I have been working towards this project for several years. In my first attempt, I did not account for the scale of the piece, nor was I aware of the method used for the groundwork. I scaled down the entire piece to fit my arm and used modern grounding tools. Since I’m much shorter than the original owner, the details were too small to fit properly on the piece. I completed the tooling as practice, but decided to discard it. As the piece was a “throw-away” anyway, I tried hot-water hardening of the tooled leather. As expected, the tooling was almost completely destroyed when the water was absorbed.
I then began some research into alternate methods of hardening in place of the SCA-traditional wax. Cennini describes how to make helm crests and parade helmets by first making a tawed leather core (similar to the method for water bottles) then hardening it with several coats of goat-skin glue. He also refers to goat skin glue being used by saddlers, but does not specify in what manner. In his description of the manufacture of this glue, he calls for the “necks” of goat or sheep parchment to be boiled in water, presumably he is referring to the waste pieces of the hide. Hide, fish (which Cennini calls leaf glue), and cheese (casein) glues were widely used in period. Unfortunately, they are also water-soluble, a characteristic unsuitable for armour. I decided to experiment with hide glue as it is readily available in granular form and thus easy to adjust the proportions.
A search of various internet sources provided a number of suggestions for rendering hide glue waterproof; adding tannic acid, alum, or skim milk, or exposure to wood smoke (formaldehyde). I then conducted a series of experiments (see notebook) to test some of these methods, as well as different consistencies of the glue to get good penetration into the leather. By the end, I had decided on alum in distilled water as my preferred method. I made two pieces of armour, vambraces and spaulders, using a post-treatment of the glue-soaked leather with alum. I then wore them for a year under all conditions. Both performed well, although the vambraces became a little sticky at Pennsic under humid/sweaty conditions. Both pieces used a fairly thick glue solution, 10:1, which did not penetrate well into the leather. I then wiped down the surface with a saturated alum solution to remove excess glue and to post-treat the glue. For this project I used a thinner glue solution for better penetration, and pre-treated the leather with alum solution.
I like the dark tone of the extant piece, although that may be age and/or conservation processes. At last year’s KA&S I entered a leather scabbard dyed with walnut dye. I decided to use the same dye to both darken the rerebraces and highlight the tooling.
Project Process – Tools:
Building on the lessons-learned described above, I began by scaling the extant piece to determine the size of the grotesques and the tools that I would need. Each creature is approximately 1″ across, and has some degree of sculpting. For these I needed a fine liner and burnisher. I already had a tool which combined both of these functions in a single tool made from antler. I used this to finely sketch the pattern, then used it again after doing the grounding to highlight the design details.
The grounding tool was more problematic. The ground on the original consists of rows of very fine convex dots at approximately 36 dpi. I could find no repeatable pattern or indication of a larger stamp. I made a single-dot stamp from antler and a multi-dot stamp from boxwood with 1/32″ holes but neither left the same impression as the original. I did notice that the original’s impressions had in places a squarish shape similar to when I have made beaded wire. I then tried scribing lines 1/16″ apart then going back over the ridges with the single dot punch but the result did not look right either. As the lines on the original are not straight it seems unlikely that the maker used a straight edge to scribe lines as for this method. It’s also a more time-consuming method, which would be unlikely for something unimportant like the grounding. The tool I used to make the beaded wire is square in section, which could leave the straight furrows seen on the piece, however, again, I could not get the same effect when I tried using the beading tool on leather. My own experiments with the single-dot tool gave results that I was happy with, and if I was careful, I could get reasonably straight lines at 20 dpi. By working away from me, and from right to left, I managed a fairly consistent pattern although I did tend to curve more than the original as my hand followed the arc of my wrist motion. It also was a little too big for the fine detail around the creatures.
In the photos above, the original (left) and my rendition (right) are compared. The grounding of the original is considerably finer, and more even, and the detail sculpting is also much finer. I need both a better tool, and much more practice.
Finally, I burnished the edges with a bone tool I had already made, and cut slots for the straps and holes for the points.
Project Process – Design Elements:
I made the right hand rerebrace first so that I could follow the original’s layout without having to mirror it at the same time. The base design is vine scrollwork with trefoils, inhabited with grotesque figures. Each creature is approximately 1″ across. I used the same creatures as on the original for some of the design, similar creatures from illuminations from the same period, and some creatures that I designed myself. Each creature was sketched in freehand on the leather with a scribe, the vines drafted around it, then the trefoils added to fill in the open areas. Care was taken with regards the interlace of the vines and overlap of the creature elements (wings, claws, tails etc.). Unfortunately, I made the griffon on the right rerebrace too big, which threw off the spacing vertically. Once the layout was sketched in, I filled in the grounding, refreshed the outlines with the liner, then added sculpting and details likes eyes.
Project Process – Treatment:
My experiments in hardening leather suggested that pre-treating the leather in a saturated solution of alum in distilled water, followed by soaking in a thin hide glue at 150°F was a workable method. I prepared the alum bath, soaked the leather until saturated, then allowed it to air dry until ready for tooling. I refreshed the leather during tooling with the same water.
The only other change I made from the experimental armour pieces was to dye the leather with black walnut husks soaked in ammonia. The dye was brushed on, scrubbed into the grounding, then lightly wiped clear to highlight the raised portions of the design. The dye was left to air dry for 24 hours.
The hide glue was purchased from Lee Valley Tools. A solution of 10 parts distilled water to 1 part glue granules was created, then left to sit at room temperature for an hour. It was then heated to 120°F in a small crock pot, when another 10 parts distilled water were added to create a 20:1 solution. The solution was heated to 150°F, then brushed onto the leather until saturated. Then leather was formed to shape, wrapped in Saranwrap to hold it in place, and left to cool for about 10 minutes. When I made the test armour, with a thicker glue, I needed to wipe down the pieces with alum solution not only as a post-treatment but to remove excess glue which lay quite thick on the leather surface. I repeated the same process but, due to the thinner glue soaking into the leather quite well, there was little excess glue to remove.
After air drying for 24 hours, I added straps and buckles purchased at Pennsic from Thor Thor. The joins were stitched with modern polyester thread rather than use even more modern rivets. In use, they will be pointed to my gambeson.
The end result was an armour with some flexibility, but, I feel, good protective properties as well. I will use them in regular combat to find how well they stand up to every-day wear and tear although based on my experiences with the test pieces I am confident they will perform well.
Lessons Learned:
- While the dot tool worked well for the large open areas, it was too big for the fine detail around the grotesques. Further experimentation needs to be done to develop a finer tool and to try different processes to recreate the grounding pattern on the original piece.
- The glue cools too quickly to get full penetration of the leather. I didn’t want to get too thin a mixture for fear that it would ruin the tooling, although the thicker solution used earlier did not penetrate well. Again, this needs more experimentation.
References:
- British Museum, item # 1865,0701.1665
- Covington, Anthony D.; “Tanning Chemistry: The Science of Leather”, Google Books version
- blogspot.ca; episode #90, discussion of hide glue in woodworking
- Cennino Cennini, “The Craftsman’s Handbook – volume 2”; translated by Daniel V Thompson Jr., Dover, 1960.
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