Tuesday, August 12, 2014

First Iron Smelt for 'Turf to Tools'

This is a fast overview of the progress so far at the "Turf to Tools' project at the Scottish Sculpture Workshop:

Team : (L-R) Thomas, James, Eden, Darrell

Air System, just as first graded charcoal is being added.

Initial Compaction - slag mass has been struck off at this point.

Forging the edges of the bloom.
I arrived at SSW later on Friday.
Saturday was filled with general preparations, and forging up some of the specialized tools expected to be needed for the smelting processes.
Sunday was preparing the ore and charcoal, then mixing the materials for the furnace and building it. (For a general description, see the earlier blog posts.)
Monday was smelt day - expected to be the first of three over the project.

31 kg of mixed ores were prepared. Primarily this was a mix of the local (unusual!) Macaulayite ore, with added industrial taconite. There was a small amount of red iron oxide analog used as well.

The furnace ran extremely well, consuming 2 kg of graded charcoal an average of every 11 minutes. This rate was much more consistent than normal in fact. Charges started with 1 kg, and mounted up to 2 kg per charcoal measure.

There was in fact more slag produced than normally seen.
The slag bowl formed higher than usual, and had a sharp edge turned up only about half way across the furnace. This was thought to be because of the blower used, which likely was not producing as much delivery pressure as the standard unit employed back in Wareham.

The finished bloom weight was just over 2 kg, not the best yield. This is considered to be an effect of the Macaulayite ore, which in fact may be a bit low in iron content. (Visually, this material looked quite 'sandy'.)
The extracted bloom, cleaned of slag, was a saucer shape, about 5 cm thick at the edges and roughly 20 cm in diameter.
Several compression steps were taken  on a large block using two strikers. At this point the 'plate' was transferred to a coal forge, where the edges were worked in and the entire mass was further compressed.
Work for this day (!!)  finished up by cutting the bloom into two rough half pieces, ready for further compacting and welding to consoldate the iron to a working bar - the work planned for Wednesday.
The initial furnace build was done

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

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