Iron Smelt at CAMELOT : Demonstration
September 14 & 16 - 2018
St Jerome's University - Waterloo

Smelt Team:
Sarah Johnston & Hayley Ellis (of St Jerome's)
'Gus' Gissing, Tyler Hickey
Smelt Master : Darrell Markewitz

My close friend and regular iron smelting partner, Neil Peterson, had long organized an event called Forward Into the Past. I had been a regular contributing lecturer and session leader over the 27 year history.  (1)
Starting in 2018, the concept of on day conference format, bringing serious 'armature' / independent researchers together with senior students and academics was taken up by St Jerome's University of Waterloo ON.
I had early on offered to undertake a full bloomery iron smelt demonstration at the new CAMELOT conference to help kick off this new series.

The full demonstration included two days, with a full day build and set up undertaken on Friday, September 14. My old friend and 'apprentice' Gus Gissing proved of immense help for the build. Neil Peterson came by later that afternoon, so was able to provide some photography of that process. 
Because this smelt was intended as a full public demonstration, as well as a potential teaching segment for St Jerome's students, a standard 'Norse short shaft' furnace was constructed :

furnace layout

Furnace Layout - note variations from a 'theoretical' build

 - Clay Cobb Construction : the usual mix of equal amounts (by volume) of powdered clay, rough sand, and shredded horse manure.
- Overall size : 25+ cm ID / 65 cm + tall
- Tuyere : forged copper - with ID at 20 mm (tapers to tip)
- Tuyere Set : roughly 20 + cm above base, at 22 degrees down, 5 cm proud of interior wall.
- Furnace constructed on a base plinth of standard concrete blocks, the central space filled with charcoal fines.

The full build is described as a separate article on the blog - HERE (2)

finished build
Dry mixing clay / sand / manure.
(image by Neil Peterson)
Lower course in process, using a metal form for consistent size.
(image by Neil Peterson)
Build complete, packing inside and rope around exterior for support.

For this smelt, the well proven DD1A analog was used, with roughly 30 kg prepared:

- 22.5 kg red iron oxide powder (Fe2O3)
- 2.5 kg whole wheat flour (10%)
- 2.65 kg collected forge scale as enrichment (roughly 10 % Fe3O4) (3)

Because of the small team - almost all who had never seen (much less participated) in an iron smelt before, there was a bit more chaos than normal here at Wareham. Additionally, the demands of explaining the process to the public would greatly reduce any photography by the working team (especially myself). (4)


Tyler and Hayley breaking ore to suitable sizes, Sarah maintains the wood splint pre-heat.

The passive display - showing materials, remains, and process.

For this smelt, the totals were :
- ore = 30.6 kg
- charcoal = 51 kg
- time = 5 3/4 hours, to extraction (another 2 hours on pre-heat)
The full smelt data is available HERE

Final bloom - showing weight in Imperial (image by Gus Gissing)

Final Weight = 5.4 kg

Yield = 18 %

Given the use of a normal ore addition sequence, the results are perhaps a bit low - but still reasonable. (Rather than the very high returns seen in the other two smelts bracketing this one, both using the early addition of iron rich slag known as the 'Nissen Method')


Remains of the furnace (with bottom extraction), seen the following morning.

1) I am listed on the FITP web site as contributing 43 individual lectures over 21 years (For the list, look about half way down - alpha by first name)

2) The description of the build is more complete on the blog post than the usual notes. This primarily because there had been a number of recent questions related to furnace construction on the Facebook 'Iron Smelters of the World' group. I was attempting to 'kill several birds with one writing'.

3) Observers will note that this 'DARC Dirt - One / Altered' has become a standard mix used for continuing experiments here at Wareham. The original mix (in 2008) was created in an attempt to mimic the primary bog iron ore found at L'Anse aux Meadows, Newfoundland. A large donation of red iron oxide powder several years back (1500 lbs total!) has allowed us to keep to a 'standard' ore quality.

4) There is a fair chance additional images, particularly of the extraction, may be available at a latter date. The extraction was timed to match the end of formal lecture sessions, and a good number of the conference attendees stayed to watch this (exciting!) process. Plenty of cameras were in evidence...

unless otherwise credited - Text and photography Darrell Markewitz