Premise / Questions:
|Diameter:||9" (22.5 cm)||Stack above Tuyure:||16" (40 cm)
with 12" (30 cm) metal collar it totals 18" (70 cm)
|Tuyure Diameter:||1" (2.5 cm) I.D.|
|Tuyure Distance above floor:||5.5" (13.75 cm)||Tuyure Angle:||15°||Tuyure Penetration into stack (start/finish)||3/4" (1.9 cm) / N/A|
|Reports of all of our iron smelting efforts along with more articles and information are available on the "Iron Smelting in the Viking Age" CD from the Wareham Forge. Copies of the CD can be purchased here.|
|Total Charcoal||124 lb (56.4 Kg)||Weight of Bloom||900 g (1.98 lb)||Total Elapsed Time:||5:46 to last charcoal added, 6:08 to next smelt fully loaded with charcoal|
|Total Ore||51.24 lb (23.3 Kg)||Weight of Slag:||Not recorded||Bloom Quality||Good soft Iron|
|Side view||Top view||Dry smelter||In progress|
The first smelt was undertaken by Neil and Dr. Ron Ross, with Darrell guiding and troubleshooting (avoiding most of the work). Once finished with charcoal, Sam stepped in as record keeper over both smelts.
As is typical, although our intention was to start pre-heat for 8 AM, getting equipment set up and everything organized always delays the start, so actually the fire was started closer to 9:45. The preheat phase was fairly standard, with the switch to graded charcoal marking the official start of the smelt after 60 minutes. Over the first smelt the furnace ran evenly and maintained a textbook burn rate of 8 minutes per standard 4 lb charcoal charge. A total of 20 kg of ore was added for the first smelt. The course of the smelt followed what has come to be the fairly standard method : heat the stack / seed charges / main charges slowly increasing in volume / allow the last charge to settle then add a larger shock charge / burn down for extraction. As was expected with the high rock ore, more glassy slag was created than in our past smelts, and several tappings were undertaken.
Neil prepared and started a top extraction. It was quickly clear that there was an excessive amount of liquid slag at tuyere level, and he was having trouble locating the potential bloom. His pounding with the thumper was found to be just splashing into a large pool of liquid slag. Darrell quickly stepped in (working without much gear on and burning off a glove in the process) and located and loosened out the smaller than expected bloom mass. Darrell then grabbed it out with tongs and quickly moved it over to the consolidation stump, where Ron / Sam / Gus were waiting with large hammers. The bloom proved to be quite spongy, but was quickly worked down to a rough block a bit larger than fist sized. The finished bloom weighs only 900 gm. It still contains considerable slag and is expected to loose a significant amount of weight as it is later further compacted in the forge into a bar. The metal appears to be of workable quality however, expected to produce a good soft iron - if only a smaller amount.
|0:00||Start Preheat, Tap arch Sealed, Air started||4||A+½|
|1:00||Switch to graded charcoal|
|1:06||Increase Air flow||C+½|
|1:42||Ore - Seed Charge (full scoop)||1||0.4||0.4|
|1:48||6||Ore - Seed Charge (full scoop)||1||0.4||0.8|
|1:57||51||Increase Air Flow||C+¾|
|5:12||Remove Metal Sleve after initial burn down|
After this we pulled the bloom and immediately refilled the smelter for the second smelt. The record of the second smelt is here.