Saturday, June 26, 2010

Currency Bar from DARC Iron

A general feeling was that we should have at least one completed 'currency bar' made up for the L'Anse aux Meadows presentation - that was formed from iron we had smelted ourselves. There was one completed billet of iron on hand. Unfortunately there are some gaps and errors in the records, so not as much information can be gained as was hoped.


Date : November 12, 2005 (note that earlier records show this as 'October 2005'
Experiment :13/D7 (detailed notes on the DARC Iron series)
Location : Wareham, ON
Team : DARC
Furnace: Norse Short Shaft
- clay cob with stone slab support
- tap arch
Note - reuse of furnace from June 05
Size : 25 cm x 60 H
Source : suggested by earlier experiments
Tuyere : 25 mm ID ceramic kiln support
Placement : 16 cm from base
- about 5 cm in from wall
- angle at 20 down
Bellows : vacuum blower
Air : 600 l / min (estimated)
Charcoal : 79.5 kg broken hardwood
Consumption : about 2 kg charcoal every 10 minutes
Ore : Stelco taconite + Virginia Rock Ore
17 kg (roasted)
Sequence : ore added in variable sequence (7 - 10 min)
as small charges .75 - 2.25 lbs
Duration : about 6 1/4 hours (not including preheat)
Result : 4.3 kg bloom
Yield : 22 %
Notes : - Successful creation of historic sized bloom
- Success in patching and re-firing furnace


My notes list an undated effort to forge down a portion of the November 2005 bloom. These seem to indicate the main part of the bloom was cut into two sections, one at 1.70 kg, one at 1.86 kg, the remainder of the mass as smaller fragments. The 1.70 kg piece was forged down into the working bar seen above. The notes list the resulting bar at roughly 2 x 3 by 34 cm, but do not give the finished weight.

This is the completed currency bar. The finished weight is 895 gms. The size is in the range of the artifact samples : 15 x 15 mm (widest portion 18 x 18) by 525 mm long.

This is a close up of the flattened end of the bar. The 'paddle' is 110 mm long, and roughly 32 mm wide. It tapers slightly from 5mm thick at the base to 3 mm at the tip.

A close up of the bar end. I developed the runic mark seen for use on DARC replica objects. In five strokes it combines all the letters for DARC, both in Roman and Norse characters.

The starting billet could perhaps have used one additional consolidation weld. There is some cracking along the straight corners of the bar as a result. The flattening step held together very well however, a step added in the Viking Age as a quality check. Overall the quality of this bar is in the same range as I found when I created a set of replica bars for Parks Canada, using various antique wrought irons.

Replica Currency Bars - for L'Anse aux Meadows NHSC, 2001

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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