15 Oct 2011 - More temperature records

The goal of this day was to get some additional temperature measurements for different designs of furnaces for a paper we are working on.

The outcome of this series was the paper:
Glass on Fire: Temperatures in reconstructed Viking Era bead furnaces, in "Can These Bones Come to Life?" Insights from Reconstruction, Reenactment, and Re-creation Vol II. It is available from Freelance Academic Press.

We ran three furnaces this time - the "Sarah", the "Goderich", and the "Neil".

Furnace Name	Archaeology	Description	Notes
Neil	Ribe Circular design	A "teapot" design. Single chimney, with annealing pot attached to one side. A single working port cut into the body. Charcoal is loaded through the working port or chimney. Walls are standard thickness (3cm) and have a very pronounced curve joining walls and floor in a bowl shape to aid in charcoal concentration. The working port is cut high on the wall.
Sarah	Ribe Oval	A smaller version of the standard shape built with a single chimney. This had originally been intended to work as a single working port but the plan was changed. A port was cut into each end, and a diverter added to the inside. The air port was cut in the usual location.
Goderich	Ribe Oval	Dual chimney oval furnace, cobb construction. Internal construction includes gentle slopes from walls to floor, and a large air diverter opposite the air port. There is no opening cut for charging - charcoal is added through the chimneys. Working ports are cut into each end. Right port uses cuts angled up into the furnace. Left port cuts angle down into the furnace. Right port produces more heat onto the bead maker.	Good functional furnace with 10 hours of burn time.

Several videos were made to allow us to plot temperature over time, both in the chimney and in the door. These are the results.

Operating temperatures

All temperatures are in celcius.

Compressed video (8x normal speed) to go with the chart below


Compressed video (8x normal speed) to go with the chart below


We also got a chance to run and record the "goderich" furnace the next weekend
Compressed video (8x normal speed) to go with the chart below


Videos

We also have a few videos available:

	Decorating a bead with reticella
	Drawing reticella rod
	Creating millifiore

Photos

The "Neil" furnace	Winding on glass	Working a bead in the chimney	Working a bead in the chimney
Temperature of "Neil" furnace	The "Sarah" furnace	Working in the door	Reticella
Pulling reticella	Adding more glass	Rolling a bead	Touchng up an edge
Adding reticella	Sarah getting ready

Beads Produced

Black - impacted by atmosphere	Blue decorated	Blue with reticella	Wasp bead
Wasp bead 2	Wasp bead 3	Rayed eye bead	Dotted
Light blue	Clear	Black with ringed eye	Second view of bead
Yellow with dots	Bead with reticella	Second view	Black with red and yellow bands
Second view	White	Two temps

Furnaces


Following this session the bead furnaces were broken down in order to record more information about their construction.

Neil

Exterior diameter of base	22.5 cm
Thickness of base	18 mm
Interior bowl width	13 cm
Depth of bowl (to bottom of door)	11 cm
Bottom of tuyure to bottom of bowl	5 cm
Bottom of bowl to top of chimney	22.5 cm

Measurement	Total (mm)	Sintered (mm)	Dark Clay (mm)
Wall at base of bowl	70.58	4.55	16
Wall half way to door	34.91	4.33	5.5
Wall at door	31.33	7.24	13.18
Wall at top of door	25.01	8.72	9.08
Wall at top of chimney	13.29	6.27	5.4

The floor had only a thin amount of sintered clay, most of it was just blackened. At the center of the bowl the black was the full thickness while at the edges there was unblackened clay at the bottom.
On the inside of the bowl the bottom is partially blackened and partially unblackened. The black area is on the side of the bowl closest to the door and covers a part of the interior wall.

Top view	Side view	Air inlet	Opened between door and tuyure
Wall above door	Side view of cross-section

Sarah

Exterior length	40 cm
Interior length	32 cm
Exterior width	21 cm
Interior width	14 cm
Interior tuyure to diverter	8.5 cm
Exterior height	25 cm
Interior height (to bottom of chimney)	20 cm
Thickness of base	18 mm
Interior bowl width	13 cm
Depth of bowl (to bottom of door)	11 cm
Bottom of tuyure to bottom of bowl	5 cm
Bottom of bowl to top of chimney	22.5 cm

Measurement	Total (mm)	Sintered (mm)	Dark Clay (mm)
Chimney	17	8.2	6
Chimney 2nd location	16	7.7	7.4
Chimney 3rd location	16.2	6.2	5.2
Top shoulder at chimney	22.5	9.2	8.2
Top shoulder at chimney 2nd location	24.8	11.9	11.9
Above Tuyure	36.5	17.7	12.8
Above Door	32.5	19.3	11.1
Wall under tuyure	35	13	19
Wall under tuyure at base	50	4.5	38.7
Base	23.4	4.7	7.3

Back view	End view	Wall below tuyure	Side view, wall below tuyure
End view with door	Base	Floor

Goderich

Exterior width of base	25 cm
Exterior length of base	54 cm
Thickness of base	18 mm
Interior bowl width	13 cm
Base to bottom of door	2.6 cm
Door height	6.2 cm
Base to top of chimney	28 cm

Measurement	Total (mm)	Sintered (mm)	Dark Clay (mm)
Tuyure wall at base	54.5	0	12.52
Tuyure wall 1" up	37.18	7.29	10
Tuyure wall 2" up	34.97	11.48	14.38
Tuyure wall 3" up	34.68	15.9	13.17
Tuyure wall 4" up	30.29	13.05	14.25
Tuyure wall 5" up	31.75	11.25	10.88
Tuyure wall 6" up	23.59	7.95	8.69
Tuyure wall 7" up	19.23	11.51	7.2
Tuyure wall 8" up	21.85	10.34	0
Tuyure wall 9" up	20.32	8.58	0
Tuyure wall 10" up	15.7	6.91	0
Tuyure wall at top of chimney	15.8	5.44	0
Back wall at base	40.68	8.24	22.61
Back wall 1" up	32.86	11.91	14.44
Back wall 2" up	35.27	10.34	19
Back wall 3" up	32.95	14.27	9.73
Back wall 4" up	29.55	13.11	8.25
Back wall 5" up	24.05	11.06	5.09
Back wall 6" up	21.83	12.62	6.01
Back wall 7" up	16.95	8.62	4.13
Back wall 8" up	17.75	6.68	5.66
Back wall 9" up	20.72	8.12	5.79
Back wall 10" up	19.24	9.11	6.32
Side wall above door	28.73	15.51	9.67
Base a door	52.78	18.91	25.07
Base 7cm in from door	25	5.82	All

The inside of the base showed almost no blackening. Just a small amount at the midpoint between the door and tuyure.
Underneath the base (exterior) heat blackening was visible in a fairly regular oval starting about 3cm from the edge. There was no visible difference in the heat marking where the air diverter is found.

End view	Back view	Top view	Air diverter
Door to back wall	Interior	Underside of base	Base cross-section
Plan drawings