Gaeira's Anvil...Blog

Visual Typology of Twisted or Plaited Viking Age -Rings. Part 1.

Various Shapes of Forged Wire or Rod
for Viking Age -Rings, Figure 1.

This is Part 1 of my blog post series on the visual Typology I've worked on for twisted and/or plaited Viking Age (VA) Finger-Rings, Arm-Rings, and Neck-Rings (-Rings).

In this post I will be covering the most important elements, the metal rods and/or wire they forged and then twisted and/or plaited to form their -Rings.

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Various Shapes of Forged Wire or Rod for Viking Age -Rings, Figure 1.

The extant finds are predominately made of Gold or Silver (sometimes referred to as Fine Silver) as well Gold Alloys (23 Karats and below) or Silver Alloys. There are also some -Rings identified as 'Copper Alloy' or Bronze.

Unfortunately, the majority have NOT been tested to determine their exact metallic compositions. Somewhat vague terms tend to be used, which can cause confusion, usually based on how they look.

Example, 'Copper Alloys' could mean any of the various Brass(es) or Bronze(s) we use today, but they are referring to Brass.

Non-Modern Labels for 'Copper Alloys'

The blanket term 'Copper Alloy' is used within Archaeology to label and encompass a variety of Brass items. The main component of Brass is Copper (Cu) and its secondary one is Zinc (Zn). Even if this alloy is referred to as 'Bronze' it is still 'Brass' because it contains Zinc (Zn) and not Tin (Sn).

Bronze is an alloy of Copper (Cu) and Tin (Sn). This blanket term does not specify the percentages of either element in the alloy, this can also be seen with the above term used for a Brass, 'Copper Alloy'.

Copper Alloy = Brass = Copper (Cu) and Zinc (Zn)

Bronze = Copper (Cu) and Tin (Sn)

The Copper Development Association (CDA)

The Copper Development Association (CDA) is an international association that sets the standards for Copper and Copper alloys. They do this by creating internationally recognised ID code numbers that should be strictly followed when using their ID Codes to avoid confusion.

For example Nickel Silver's CDA code number can be written in any of the following formats:
CDA#752, CDA #752, CDA 752 or Alloy 752, etc. This specifically identified Copper alloy contain 65% Copper (Cu), 17% Zinc (Zn), and 18% Nickel (Ni), and it goes by various names depending on the sellers preferences: Nickel Silver, German Silver, Nickel Alloy, etc..

The CDA code number can be written in many different ways, as seen above, and yet mean the same thing. Using the CDA approved code for a specified Alloy ensures that the mix of metallic elements, that we are referring to, is the exact Alloy we mean so that there is no doubt.

I have been unable to find a complete list of the CDA's standards and Alloy code numbers, on any of their websites. Most vendors use different terms for the same Alloy which quickly gets confusing so I compiled information from various websites, PDFs and tables into a table on my personal website entitled, 'Metal Alloy Table'.

For additional information and links please see the section entitled, 'Copper Development Association (CDA)' on my 'Metal Suppliers' resource page.

Modern ID Codes for Copper Alloys

CDA#230: The modern alloy containing 85% Copper (Cu) and 15% Zinc (Zn), is referred to as Red Brass, Jeweler's Brass, NuGold, Jeweler's Bronze, etc..

CDA#260: The modern alloy containing 70% Copper (Cu) and 30% Zinc (Zn), is referred to as Yellow Brass or Cartridge Brass, etc..

Modern ID Codes for Copper Alloys: Bronze

CDA#521: The modern alloy containing 92% Copper (Cu) and 8% Tin (Sn) is Bronze and it is also referred to as Phosphor Bronze or Grade "C" Phosphor Bronze.

CDA#521 is also significantly close to the proportions of tested extant Bronze items.

Forging an Ingot into Various
Shapes of Wire or Rod, Figure 2.

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Forging an Ingot into Various Shapes of Wire or Rod, Figure 2.

On a flat anvil, place your wire or rod while holding it with a pair of pliers, hammer from one end to the other along each corner's length and use consistent force. Rotate the wire or rod a quarter turn and repeat these steps until it has parallel sides and a polygon cross-section.

Stages:

Ingot > Square [4] > Octagon [8] > Hexadecagonal [16] > Triacontadigonal [32] > Circle

Anneal when the metal's length is doubled or the thickness is halved. Use the appropriate heat for the metal being used, immediately quench it in clean water. Use non-Ferris tweezers to place it in a warm pickle solution to remove any oxidation. Thoroughly wash the metal and dry the surface before continuing.

Annealing returns work hardened metal to dead soft by returning its Ductility.

Remove the ragged ends with a saw or use a sharp cutting chisel. Rotate a 1/4 turn after each chisel strike and repeat until you cut through. Leaving the ragged ends could leave cracks or flaking that could get bigger as you work the metal causing a great deal of damage.

Late Anglo-Saxon Disk-Brooches. Part 6. (Enamelling Tools)

Goldsmithing and Enameling Tools: Iron Hoods / Muffles and Trays.

This is Part 6 of my series of blog posts related to my Late Anglo-Saxon Enamel Disk-Brooch project on the historical tools used in Goldsmithing and Enamelling from approximately the 2nd-century BCE until the middle of the 2nd-millennium CE.

Figures A to J.

I was inspired by the hood/muffle sets that two fellow Enamelers each fabricated and based on Theophilus' description from, 'On Diverse Arts'. A couple of years ago I saw the set made by THL Alys Treeby, my Apprentice Belt-Sister, she's had multiple successful enamel firings on a Blacksmith's charcoal heated forge. Recently Sir Ælfwyn Langanwuda sent me photographs of the set she fabricated. This past weekend she was able to use it with great success on her period bead kiln that she's repurposed, previously she used a blacksmith's forge as a heat source. Both of their hoods are appropriately 3-inches in diameter.

In May of this year, Doug Colin Guyton fabricated for me a perforated, domed hood/muffle and tray (see Figure M.) based on my research of Theophilus' Treatise, ‘On Diverse Arts’. Both the domed extant and reproduction pieces have handles though shaped differently. Theophilus' description is of a flat tray similar to a pizza paddle, and the domed Georgian extant tray is concave, similar to a frying pan.

Figures K and L.

Over the next year I plan to experiment with my muffle set using a charcoal forge to solder, enamel and fuse. I hope to fabricate another domed muffle/hood as well as conical shaped ones, based on the extant finds of the “Iron hood, Vani, second half of the 2nd century B.C.”.

The hood/muffle and its tray are used on a charcoal forge (see Figures B and O) or with a furnace, both are smaller than what Blacksmiths use(d). They are placed on top of heated charcoal and other heated pieces of charcoal are piled a couple of inches high around the hood. Since the holes in the hood/muffle were punched from the interior outwards, the sharp edges of the cut and stretched metal point outwards, much like a cheese grater, and help reduce how much ash and particles can enter. The charcoal quickly heats the metal and interior space. Once the needed temperature range and time have been reached then the charcoal can be carefully brushed away from the sides and the entire hood/muffle and tray can be removed from the forge or furnace.

"A copy of the Colchian cloisonné hood was made and tested, which showed that the Colchian “hood" is a goldsmith's tool – an iron muffle. If placed underneath a pile of burning coals as described by Theophilus, high temperatures are achieved inside the muffle and a highly skilled jeweler can perform work on glass, gold or silver." (Ermile Maghradze, Nature, June 2014)

I am researching the writings of three other historical figures in hopes of finding more information on the tools and techniques of pre-Renaissance soldering, fusing, and enameling techniques. I will continue to write blog posts of my experiments and findings over the coming year.

Figures M to P.

Figure A.

Ermile Maghradze fabricating a Gold Cloisonné enameled medallion based on an extant find.

Figure B.

One style of “Colchian hood” being used for Georgian style enameling on a charcoal forge. The one shown above is a reproduction based on an extant find (see Figure K and L).

Figure C.

Ermile Maghradze placing Gold cloisons on the back plate.

Figure D.

The perforated, domed hood looks like Theophilus’ description in his Treatise, ‘On Diverse Arts’, though this extant Georgian base is concave, similar to a frying pan, instead of flat like a pizza paddle, as in his description.

Figures E & F.

“Iron hood, Vani, second half of the 2nd century B.C.”, a conical style of perforated muffle / hood and its base, displayed in the Georgian National Museum.

Figures G to J.

A variety of Georgian Cloisonné enameled pieces.

Figure K.

The various tools used for fabricating Georgian enameled pieces, several are extant finds (both hoods), others are modern recreations based on finds and research.

This conical hood is very similar to the “Iron hood, Vani, second half of the 2nd century B.C.” from page 57 of the article.

The perforated, domed hood looks like Theophilus’ description in his Treatise, ‘On Diverse Arts’, though this Georgian base is concave, similar to a frying pan, instead of flat as in his description.

Figure L.

"One very important archaeological discovery in Western Georgia was a perforated, cone-shaped iron “hood” and a tray discovered in 1966 in the remains of a city near Vani in the historical region of Colchis. We made a link between this artifact and a type of “hood” used to mount enamel, which had been described by Theophilus. In the chapter of the treatise that explains firing gold plate with mounted enamel, Theophilus describes a “hood” with a tray that a smith has to use to complete the firing. It is apparently very important that Theophilus is describing one of the types of muffles (a clay or iron box inserted into a furnace in order to fire an article) that was widespread in the medieval goldsmith workshops."

- from, Ermile Maghradze (2014) 'The Discovery of the “Colchian hood”, a tool that shaped the art of Medieval Cloisonné Enamel Technology', Museum. Georgian National Museum, N1, June 2014, 54-57.

Figure M.

This perforated, domed hood was fabricated by Doug Colin Guyton based on my research of Theophilus’ description from his Treatise, ‘On Diverse Arts’.

The base of the domed Georgian extant set is concave, similar to a frying pan, instead of flat like a pizza paddle, as the version that Theophilus was familiar with.

Figures O and P.

The conical hood is similar to the “Iron hood, Vani, second half of the 2nd century B.C.” from page 57 of the article in Nature. Its base does not have a handle like the domed hood.

Figure P.

Figures A thru J, N, O, and several quotes are from:

Ermile Maghradze (2014) 'The Discovery of the “Colchian hood”, a tool that shaped the art of Medieval Cloisonné Enamel Technology', Museum. Georgian National Museum, N1, June, 54-57.

Figure M.

Photograph by Gaeira Aggadottir.

Figures K, L, and P.

These images are from the Georgian National Museum’s website.

Etching...Uncovering the Hidden Image. Part 4

Figure 1. Chemical ‘Wet’ Etching,
Undercutting, and Resist Lifting

This is Part 4 of my series of blog posts on how to chemically Etch Copper Alloys using Toner Transfer Paper (TTP) or Press-n-Peel Blue (PnP, or PnP Blue) sheets as the main Resist. Please see Part 1 of this blog post series for general information and additional tips, several points are not repeated here.

This blog post adds details related to Part 3's figure, "The Process of Chemically Etching Copper Alloys", please see it for further details that are not repeated here.

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Chemical ‘Wet’ Etching, Undercutting, and Resist Lifting

1. The Depth of the Etch is determined by: length of time, types of Metal and Etchants, as well as the strength / age / temperature of the Etchant.

2. Narrower lines are shallower and thinner than (3.) Wider lines.

4. Undercutting: The Metal is left in the Etchant for too long or it is too strong or new and it begins to erode away just under the resist’s edges causing an inconsistent and rough outer edge.

5. Resist Lifting: The Resist did not bond well enough to the surface, it either flakes or lifts off, the Etchant flows under and etches the new areas.

TO GO TO PART 1
TO GO TO PART 2
TO GO TO PART 3

Resource: My Video Tutorials and Demos on Vimeo

Gaeira's Anvil...Videos

You can now find my Video Tutorials and Demos on my Vimeo page, Gaeira's Anvil...Videos

I will be uploading my videos on my Vimeo page instead of on fb and posting information and a link as I make and upload new ones.

Please leave constructive criticism so I can improve my future video sessions. The 4 current ones, which were previously posted on FB, will most likely be replaced at some point with updated versions as I improve my video making skills.

https://vimeo.com/gaeirasanvil

Late Anglo-Saxon Disk-Brooches. Part 5 (Display 1)

Figure 1. Close up.

This is Part 5 of my series of blog posts related to my Late Anglo-Saxon Disk-Brooch research and fabrication Project. Part 1 is a general history of the disk-brooches that my research and fabrication project centers around.
On Sunday, August 4, 2019 I participated for the first time in the 22nd Annual Known World Arts & Sciences Display at Pennsic 48 with phase 1 of my Late Anglo-Saxon Enamel Brooch Project. From 1pm to 5pm I was one among a few dozen artisans displaying their projects from across the SCA Known World.

The 9 glass bottles on the right half of the display are of my White Paste experiments which I'll be writing a blog post about in the near future.

The colorfully filled glass bottles on the left half of the table are the enamels that I made from hand grinding several soft glass Lampworking rods of CoE 104 glass. [See Part 2, Part 3, and Part 4 of this blog series for more details.] The back row are the first 5 colors of glass rods that I ground. They were unfortunately contaminated from the marble mortar and pestle I used when I started this project. The front row of 6 enamels were entirely hand ground using a Stainless Steel mortar and pestle and fired beautifully as enamels. I switched to Stainless Stell once I read a passage from Cellini's Treatise in which he mentions using Steel, this made a great difference.

Figure 2. Full display.

It was far too windy to put out either the small Sterling Silver bezels I enameled, the glass beads I set with White Paste in bezel settings, and sample pieces of the glass rods. I will need to attach them to a sturdy backing before St. Eligius Arts & Sciences Competition in mid November, hosted by the Barony of Dragonship Haven, so they can be seen without risking their loss to wind or by getting tipped over.

These are 3 of the 4 currently printed out binders of my research sources. I've found other papers that I need to print out.

The two cutting chisels and Muffle set were made by Doug Colin Guyton. The overall muffle design is based on my research of both Theophilus and Cellini's Treatises. The muffle top is also very similar to one of the extant finds of Georgian enameling muffle covers in the Georgian National Museum.