Two - Virginia Ore in Flue Tyle
Early Iron 3 - Peter's Valley Craft Center
October 9, 2006
This second smelt was with the assistance of Dick Sargent,
and was fired on the wrap up day on Monday Oct 9. In past years this
day sees the departure of most all the participants early in the day,
with only the four of us team leaders hanging over till the Tuesday.
Also this has come to be 'weird smelt day' - usually some
wild idea contributed by Mike McCarthy.
Mike's weird idea this time was 'stick it too it'. Instead of our
standard slow ramping up of ore from a single scoop / pound per
charcoal charge (4 lbs in this case), we STARTED ore charges at close
equal amounts of ore to charcoal. This amount was increased from that
level to about as large an amount as the smelter could stand. The
maximum ore additions reached 6 lbs per bucket, with 4.5 lbs each 9
minutes being the averages.
If you want to see the field data for this smelt - go HERE
The smelter was a re-use of the standard Flue Tyle teaching /
experimental test bed developed by Lee & Skip. They had set this up
for a Saturday demonstration smelt, which was undertaken by Mike
assisted by Lee. The furnace was in pretty good shape, just needing a
bit of patching with clay around the tap arch and the tuyere. For the
Monday smelt I used one of my normal ceramic tube tuyeres, but one of
Lee's high volume blowers. (Sorry - I don't have air volume numbers for
these - but it would be the range of 1000 litres per minute.)
The overall numbers were a bit surprising. Roughly 100 lbs of the
Virginia Rock ore were charged (about 45 KG). Because of the high ore
additions, considerably less charcoal than normal was consumed, roughly
130 lbs total (58 kg). The smelt was also faster considering its
volumes - about 4 1/2 hours altogether (plus an hour for pre-heat).
The end result of this smelt was a very nice solid bloom. Extraction
was basically from the bottom. Unfortunately there was no large sized
scale on hand to get a finished weight. The bloom was slightly
consolidated, then sectioned in half, and one half into quarters.
Lee and Mike had been working in the forge most of the day on a
sculptural piece created from the bloom they had made on Saturday.
Normally I'm pretty beat after a day long smelt, but they were keen to
compress my quarter section to see what the quality was. Under Lee as
forge master, with most of the striking labour supplied by Mike, and
some contribution of myself as second striker, the section was forged
to a very faithful replica of a Viking Age anvil.
The finished object is rough cube 3 inches (7.5 cm) on a side. Finished
weight is almost exactly 2 kg (roughly 4 1/2 lbs). It tapers
slightly to the base (to permit solid mounting in a wooden stub
latter). One of the sides shows fracturing, but it was decided to leave
this crack as is rather than weld it shut. This was done to accent the
nature and origin of the source material. At this point the surface is
just hammer flattened. I have not decided if I will actually
further smooth or polish the face. As it is the anvil will certainly
serve its function. Right now the remaining three faces have two
differing rough radius curves and one section that is relatively sharp.
Again these edges could be dressed to even them up, but they will
certainly prove functional. Lee's estimate of the relative carbon
content (based on his extensive experience forging out blooms) is that
this iron is some place between a 'pure' wrought iron and a modern mild
steel in carbon (say equivalent to a 1010 material).
We all were extremely happy with the result. Although there are no
measurements of the starting weight of the bloom before forging, the
comparison of the ore weight to finished object is of note. Although
not an exact ratio, the finished production yield is roughly 18% -
considerably better than has been suggested by some other researchers
Text and photography ©
1998 - 2007, Darrell Markewitz