Beads at Upper Canada Village - June 2017

Each year Upper Canada Village in Morrisburg, Ontario takes a step to the side from its Canadian Settlement timeline to host a Medieval festival. We were asked to provide a viking element for this three day festival including their education day for the students on Monday. The bead work is one of the mainstays of our presentations.

Photos

Making Reticella	Ragnarr Bellows	Mixing Clay	Beadmaking
Ragnarr Bellows	Ælfwyn bellows	Talking beads	Beads!

While the dominant purpose of this weekend was to provide a public demonstration of Norse bead making to the general public, this doesn’t mean that we can’t we can’t learn something ourselves.

Title: Bellowing Ash
Series: Ash, Ash, Go Away
Background:
The furnace is based on hearth ÆZ from Ribe - a 30x60cm oval base. For this design the primary air inlet (a standard 2.5 cm I.D. port) was inserted at one end of the oval, and the chimney was set up close to the opposite end.

Specific Question: Will placing the chimney a further distance from the air inlet reduce the amount of ash being deposited on the glass.

Materials:

• Furnace: Cobb (clay, sand, horse manure, approximately 1/3 of each material)
• Charcoal: Royal Oak (sized)
• Glass: Standard 104 CE lampworkers glass
• Air source: Bellows (0.4 L/m)

Steps:

1. Build: Using the cobb mixed build the furnace to shape
2. Harden: Allow the furnace to air dry
3. Sinter: Using a wood fire, dry the clay, slowly raising the temperature as the water is driven off to sinter the structure to a ceramic
4. Preheat: On the day of use - use wood to gently warm the body of the furnace
5. Fire: open the top, load charcoal, close the top. Seal the top in place using a clay/water mix. Turn on air.
6. Work: At temperature (c. 800C) make the beads.
7. Recharge: when the temperature drops too far to work glass, open the top, refill with charcoal, replace and re-seal the top and start again
8. Cool: When work is done for the day allow the furnace to cool
Variables:
The air inlet change and the chimney position were the primary modifications over previous oval oven designs. A hole in the right bellows bag likely decreased the volume of air being pumped.

Observations:
• Ash levels in the beads seemed to be about the same as always if not even a little heavier
• Loading was made through a door at the end opposite to the tuyere. This meant that when reloading the charcoal, it had to be pushed the length of the oven. This decreased the volume of charcoal from what would be added in a top load.
• The air from the bellows did not penetrate as far as the chimney. There was a burn channel down the middle, with the edge of the “burn bowl” ending about 5 cm from the closest edge of the chimney.
• Working times for making beads were much shorter. It was difficult to produce a bead that included decoration. However, Ragnar was able to use it to produce a full rod reticelli with Emunder at the bellows. This demonstrated that the glass was above the softening point of glass, but not by much.

Conclusions:
The movement of the chimney does not appear to be the right solution. It did not reduce the ash visibly, but it definitely reduced the heat generated at the chimney.



Title: Air Power
Series: Blow wind blow
Background: The furnace is based on a 30x30 cm round base in the standard teapot design.

Specific Question(s): What effect does the bellows operator have on the charcoal burn pattern?

Materials:
• Furnace: Cobb (clay, sand, horse manure, approximately 1/3 of each material)
• Charcoal: Royal Oak (unsized)
• Glass: Standard 104 CE lampworkers glass
• Air source: Bellows (0.4 L/m)

Steps:
1. Build: Using the cobb mixed build the furnace to shape
2. Harden: Allow the furnace to air dry
3. Sinter: Using a wood fire, dry the clay, slowly raising the temperature as the water is driven off to sinter the structure to a ceramic
4. Preheat: On the day of use - use wood to gently warm the body of the furnace
5. Fire: open the top, load charcoal, close the top. Seal the top in place using a clay/water mix. Turn on air.
6. Work: At temperature (c. 800C) make the beads.
7. Recharge: when the temperature drops too far to work glass, open the top, refill with charcoal, replace and re-seal the top and start again
8. Cool: When work is done for the day allow the furnace to cool

Variables:

Using different bellows operators for a charcoal cycle: adults (Ragnar and Hrobjartr) and children (Emunder and Keiran). A hole in the right bellows bag likely decreased the volume of air being pumped.

Conclusions: The children definitely appeared to have a lower air penetration.


Text © Robert Schweitzer
Photographs © Individual artists
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