Recreations of 14th Century Plaque Belt, Belt Hangers, Sheath and Rondell Dagger

Introduction:

The plaque belt was in the height of fashion during the high Middle Ages, or Transition Period in the 14th Century. As seen on Edward, the Black Prince of Wales’ effigy (Figure 1), the belt was adorned with many heraldic castings or stampings around the girth.

The Rondel dagger was also born in the 14th Century (Figure 4), and quickly became the prominent sidearm worn opposite of the sword. It reigned throughout the 15th century as the secondary sidearm of the knight. Although no sheaths survived, it is understood that these daggers would be accompanied by a leather sheath by depictions on many effigies. We can tell by these effigies that the sheath had a metal chape at the tip and metal locket at the throat. The locket did not cover the forward rondel.

This project is centered on producing a plaque belt with artistic elements of my personal badge, the rondel dagger, the sheath with chape and locket, the period bar mounts to match the belt and dagger timeframe, and the accoutrements for attaching the work together (little metal bits).

As this project was started nearly eighteen years ago, there are many varied techniques of modeling, casting and enameling used. The plaque belt was cast and enameled circa 2006. The dagger was forged and fitted with the handle and rondels around the same year. The sheath was originally made during this timeframe, yet augmented with the chape, locket and harness being modeled, cast and "enameled" this year. The bar mounts were also modeled and cast this year. This project demonstrates the opportunities for various approaches to the overall lost wax casting process.

Approach:

Casting is the art of duplicating an original shape by surrounding the shape with a mold, removing the original shape, and pouring metal into the void left by the shape thus capturing the details of that original shape in metal. There are many approaches to casting in period: Sand casting, Split Mold Casting, Slip Mold Casting and Lost Wax Casting (LWC), to name the more prominent approaches. For this project I have utilized the LWC method and will focus on the processes used. The LWC method is to create an original shape with wax or other material that can be liquidized by applying heat. That original is then surrounded by an investment that starts off in a pliable or liquid state and congeals or solidifies around the wax original. This investment material needs to withstand the high temperatures of the molten metal. Then the wax is melted out of the investment, creating a negative void of the wax original. Then molten metal is poured into the void, and once solidified, the investment is removed to reveal a metal object with the same details as the original wax shape. The original wax shape as well as the investment form are destroyed in the process, thus the term Lost Wax Casting.

The approach to producing the original wax shapes for the castings for this piece is twofold: The belt plaque originals were produced with carving the original models from wax in the period fashion. The belt bars, chape and locket were sculpted using a 3D computer program and resin printing technique (a modern approach to produce a similar lost wax original). They were all then cast using the lost-wax casting techniques as outlined by Theophilus, Biringuccio and others. Some materials in this process were substituted for improved performance as described below.

The plaques on the belt were enameled using a period enameling process and materials. The chape and cope were augmented with color using a more modern technique.

The dagger is hand-forged and heat-treated using techniques that were used in period. The dagger handle was hand carved. Now these heat-treating techniques were treated as a State secret during the time that Toledo steel was deemed the superior product, so once you read of its process for heat treating, you will be considered to be in a confidence.

Materials:

Material Usage	My Materials	Period Materials
The Plaque original unrecoverable model sculpture (lost wax)	Microcrystalline Wax	Bees Wax1
The Model Sculpture materials for the Chape, Locket and Rigging Clasps (lost wax)	Castable Resin (Siraya Tech Cast)	Bees Wax1
The Final Cast Material (Plaques, Chape, Locket, Rigging Clasps)	Silicon Bronze (95% Cu, 2% Tin, 2% Si, 1% Mn)	Bronze (4:1 Cu/Tn Varies)1 or Gold or Silver. Pewter and Tin were discouraged.
Plaque Enamel	Metal Enamel - Rio Grande commercial, glass based.	Copper Carbonite Cu3-(CO3)2OH2 + Crushed Glass
The Duplication Mold - Investment Materials	Refractory Ceramic Investment (Prestige Oro)	White, thinned clay (porcelin)1 or gesso (gypsum)2
Belt	Tanned Leather – White dye (commercial)	Tanned Leather – If white it would be of Lead Carbonate – Discouraged for health reasons
The Sheath	Leather with silicon bronze chape and locket.	Most likely as seen on effigy - leather, none survive with bronze chape and locket
Rondel Dagger Blade	1060 Carbon Steel plate with 0.6% carbon – can be used for spring steel	Bloom steel. Varied in carbon content. A good target for the carbon content would be between 0.6-0.8% Carbon
Rondel Dagger Handle	Cocobolo Wood – spiral carved	Unknown – Possibly ash or oak
Rondel Dagger fore and aft guards	Brass (Cu + Zn)	Brass or bronze (Cu+Tn) or (Cu+Zn)
Rigging	Tanned Leather	Tanned Leather

Process for Utilizing these Materials:

Sculptures:

The original lost wax sculpture in period would have been carved from bees wax(2) with very early forms using tallow. The artist would produce the sculpture by carving it by hand, using files, pics and scrapers.

For the plaques of this project, I sculpted the original with a micro-crystalline carving wax (Figure 1) using files, pics and scrapers as in the medieval methods. The micro-crystalline carving wax is a firm wax that holds the details of the sculpture with the ability to withstand the heat of one’s hands. Bees wax carving in South Louisiana is difficult at best, as the heat and humidity tend to make the wax too soft to handle and manipulate without losing the detail of the carvings. I am sure that this was much easier in the mini ice-age of the middle ages.

There are multiple ways of creating multiple copies of a carving. The hardest is to carve each piece individually, however this is certainly not prudent for a plaque belt of many findings. Conversely, the original wax plaque can be cast in a period lost-wax process and then that secondary original then used in a sand cast process to produce multiple copies in metal. It may have been possible to sand cast the original wax a time or two, but for as many copies that are required for a plaque belt, the original wax would have lost the details. Sand casting is possible for these reproductions of the plaque belt as my original carving did not have any undercuts (a result of overhanging metal where the original cannot be pulled out of the mold without affecting the form). Two-part mold casting is also an approach that could be used, which is also a period method. This requires carving the details directly into a material that can withstand the temperature of the metal you are casting, or creating a front and back plaster mold of the originals (Figure 5). The split molds are carved or set and then the metal is poured into the void between the split molds to produce multiple copies.

For this project I have chosen to focus mainly on the lost wax method for all of the components. I therefore used a modern method of producing multiple wax originals from my original wax carving. This original wax duplication process is called injection molding. Once I had the original wax carving, I created a mold around the original wax carving using a two-part epoxy-like material called Room Temperature Vulcanization (RTV) liquid. It feels like silicon once the RTV sets around your original. Then, once the original is cut out of the rubberized mold, wax is then shot into the void of the mold, thus producing multiple originals of wax. Although I did not have any undercut in my original plaque wax carving, the RTV is able to be used with undercut originals as it flexes around the undercut when removing each copy without affecting the overall shape. Ultimately, I have used this method to create multiple wax carvings that are then treated as individual originals which can then be applied to the period lost wax methods.

Recently, I have begun modeling my original sculptures using 3D modeling on a computer and creating the original wax-like sculptures on a resin 3-D printer. The The chape, lockets and rigging clasp sculptures were modeled using Blender and Chitubox software. I printed the originals using a 3D resin printer (Elegoo Saturn) using a resin specifically for Lost Wax Casting (LWC) (Siraya Tech Cast). This resin performs like wax and can be completely melted out of the investment mold. The printed originals were placed on a tree to be entombed within an investment form. The originals are melted out of the form, and molten metal poured in their place.

For all these castings, I used a sprue (channel) of wax to allow the original wax to escape and the metal to enter. The ‘tree’ consists of the trunk sprue coming up from a base support, with several original wax forms branching from the main tree sprue (Figure 4). We have evidence of multiple castings being performed at once, as identified in the Split Cast mold for buckles (4) from the 14th Century (Figure 5).

Investment:

The investment is a ceramic, earthen or clay material placed around the original wax sculpture. It can sustain high temperatures without damage when subjected to the LWC burnout process of melting out the wax and when pouring in the molten metal. The common investment material used in period for LWC was white, thinned clay mixed with dung, set to age, then strained to create a slurry slip (1), or to use gesso (otherwise known as gypsum) (1). The gesso used in period is basically Plaster of Paris. It is a calcium-based material.

For this project I used a commercially available refractory ceramic investment (Prestige Oro) to create the mold. This material is silica based. This allows the ceramic investment to be semi-porous which assists in the vacuum casting process. This vacuum casting process aids in the removal of air around the sculpture while applying the investment, and secondarily aids in drawing the molten cast material into the voids within the investment. The period process is the same fundamental approach, yet without the porous material and the assistance of the vacuum there is more post-filing and cleaning required to remove the blobs of metal that fill in where the air pockets clung to the original wax. The other difference in approach is that the Plaster of Paris would have been painted on in subsequent layers (3) (Slip Molding) instead of bulk pouring a liquidized investment around the original surrounded by a flask to contain the liquid investment.

The investment is then heated to allow the wax to melt out. In period it was typical to place the investment by or over coals. In this case, I used an electric oven to slowly ramp up the flask temperature. This avoids cracking the details in the original form from the wax expanding in the form prior to the sprue melting thus allowing expansion room for the mold details. (Figure 7)

Cast Material:

The extant material for castings of this sort would have been gold, silver, or bronze (3). Bronze is a generic term for a copper-tin based alloy, with other constituents being manganese, silicon and/or other trace materials. Where bronze is an alloy of copper and tin, brass is mainly an alloy of copper and zinc. Both were used in period. The medieval castings utilizing bronze used mostly copper and tin in varying ratios. The proportions varied widely between 67 and 95% copper. A common ratio used during the Middle Ages is 4 parts copper to 1 part tin by weight (1). This ratio became known as bell bronze in later times. However, the stoichiometric ratio not realized until much later is 9:1, giving the best hardness. I used bronze for this project as gold and silver would be too expensive for reenactment purposes. The bronze metal utilized in the casting includes Copper, Tin, Silicon and Manganese, giving the bronze a high sheen with minimal repetitive buffing requirements to maintain the sheen of gold.

In period practice, the metal was melted in a crucible made of crushed pottery and dung mixed with clay and allowed to bake. The crushed pottery, or Grog, and the dung allowed the clay to withstand the higher temperatures of the furnace without cracking. I have used a graphite crucible for safety, as pouring molten metal is inherently dangerous and a failed crucible could be life threatening.

The metal was melted in the crucible in period times using air-assisted coal fire, or a forge. The air was driven by double-acting bellows (5). I have used a gas-fired forge.

The molten metal is then poured into the hot investment form (Figure 8). Again, my pouring process is assisted with a vacuum pull on the metal through the porous investment medium, but the essence of the process is the same.

The period method of extracting the casted duplicate from the Plaster of Paris investment is to break it out by chip and hammer. The silica based investment offers the added benefit of being able to quench the flask of investment while still hot, yet while the metal has solidified. This quenching action disentigrates the solid investment thus revealing the casting. I quench the flasks while the button, or cup of metal at the pour site, is between 650-675F.

Enameling The Belt Plaques:

In period, crushed and ground glass was mixed with a pigment, applied to the artwork (often with a quill), then heated over coals to produce an enameled finish (2), The pigment varies for the color needed. Blue is one color where an actual metallurgical compound was used. The early compounds used for blue were Copper Carbonate (Cu3-(CO3)2OH2) (2).

I have performed the same process however I have used a commercially available enamel (Rio Grande Enamel - Blue). It is a glass-based enamel, yet the coloring compounds are proprietary. It is lead-free for safety.

The "enameling" on the chape and locket are a UV light activated fingernail polish. I wanted to try this method to compare it to the period enamel. It is not as durable, yet it appears with the same luster.

Forging the Rondel Dagger:

The forging process is in itself a full topic of discussion to capture the nuances and differences between the modern and medieval process. I started with a sheet of ¼” thick 1060 steel plate and a forced-air charcoal forge I have built. With a hammer and anvil, I forged the blade shape. With a grinding wheel I finished the edges. I then heated the blade to a point where the material was no longer magnetic (a magnet would not stick to it). Aligning the spine of the blade to magnetic North, I quenched the blade in peanut oil. At this point, the metal is in the Martensitic phase of steel. It is extremely hard, like a ball bearing, yet also extremely brittle. In order to temper the steel to be usable while still maintaining an edge, I heated it to 350F for one hour, or until the steel had a wheat-like patina. At this point the metal is in an Austenitic phase, which allows it a sufficient amount of strength while still maintaining the ability to keep an edge.

Carving the Dagger Handle:

I used a solid piece of Cocobolo wood and carved the final shape and spirals in the handle. (Figure 12). Cocobolo is a South American wood. Medieval blades would have used mainly oak or ash, as these were popular hard woods used for carved bodies.

Conclusion:

This project assisted me in learning the medieval techniques of casting and forging, while incorporating modern techniques of casting for better detail in the final pieces.

Bibliography:

1. Bartlett, Robert Medieval Panorama Thames & Hudson Ltd, London 2001 ISBN 0892366427

2. Hawthore, John G Theophilus – On Divers Arts The Foremost Medieval Treatise on Painting, Glassmaking and Metalwork, Dover Publ., London 1963 ISBN 048623784

3. Ashbee, C.R. – The Treatises of Benvenuto Cellini on Gold Smithing and Sculpture Dover 1967 ISBN 1428604308

4. Whitehead, Ross Buckles 1250-1800, Greenlight Publishing Great Britain 2023 ISBN 189773817X

Hoover, Herbert - Agricola, Georgius - De Re Metallica, Martino Fine Books 2014/1912 ISBN 9781614277460

5. Mills Nigel Medieval Artefacts Catalogue and Price Guide Greenlight Publishing Great Britain 2017 ISBN 1897738277

6. Rondel Dagger Royal Armory Leeds, Great Britain Item X1