Monday, September 19, 2016

Iron Smelt in Poland (one)

I do need to write more about the iron smelting symposium in Pruszkow Poland - and how I got to be there.
The team working area on Friday.
Jens & Lee at the rear (Michael's furnace).
Tom central with his and Jens' furnace.
My furnace at the front.
For now, a short look at the two iron smelts I undertook there...

'Loki at Pruszkow'

About 3 1/2 hours into the smelt.
Norse Short Shaft furnace :
70 cm total height = 20 cm base depth / 50 cm stack height
28 cm interior diameter, cylindrical
Copper tuyere : insert 5 cm, angle about 20 degrees
Air from Danish 'standard vaccum' set about 2/3 volume (??)
Ore 'Goldere' and 'Harres' from Denmark, total 30 kg
Charcoal type unknown, total 46 kg +
Total Time : main sequence about 5 hours to extraction

Remains of the broken furnace after the smelt. (Snorri looks on)

An attempt was made to undertake a top extraction. It did not prove possible to find an edge of the encased bloom.
At that point a normal bottom extraction was undertaken. During the smelt however, there had been very little slag removal via tapping. For that reason there was a very large slag block filling the entire base of the furnace.
In the end it proved necessary to simply break off the top shaft, basically at the top edge of the tap arch. This then exposed the entire slag bowl, and it was possible to grab the bloom.
'Loki' bloom, partially compressed.
Total Bloom Weight = 5.80 kg
Yield = 19 %
side view of the interior cut section

For comparison, look at this Viking Age artifact bloom (one of very few recovered).
There are a number of similar features.

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

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