Materials Test - Lyndhurst at CAMELOT

Although the Bloomery Iron Smelt undertook last Fall at the CAMELOT conference was primarily a public demonstration of the physical process, the concepts of Experimental Archaeology were also illustrated.

Additional Descriptions:

Furnace Build  

Experimental Overview

 

Ore Analog addition - main sequence

There was also a small experimental materials test integrated into the two day demonstration.

Regular readers may remember that I took part as a 'digger' volunteer at the ongoing excavations at Lyndhurst, Ontario, late August 2018. (1)

This illustration does not quite match the actual ground contours!

The original Lansdowne Iron Works is the first full scale commercial iron processing in what was then known as Upper Canada, dated to 1802- 1811. The complex included a blast furnace (producing cast iron) on the east bank, and a bloomery iron furnace on the west bank.

One of the main reasons for establishing a major iron processing facility has always been the local availability of the main raw materials : suitable iron ore and abundant wood for charcoal. A third element is the type and quality of the materials needed to construct the furnace itself. (2)

Of course limestone, which dominates the geography of the lower end of Southern Ontario, is not really suitable for construction of iron smelting furnaces. (3)
Lyndhurst however, is in the region of Ontario where the granites of the Northern Shield transition into the limestone covering Southern Ontario and New York state.

There was a thick deposit of clay also underlaying the modern backfill layer which has been placed over the ground level were the 1800 bloomery furnace was built. Clays, often modified with the additions of sand or organic materials has proved a very effective building material for furnace construction.

So - as part of my time at Lyndhurst, I gathered some of the clay from the furnace level, and some small fist sized stones from local rock cuts.

The raw clay was a medium grey colour, with what appeared a fairly high sand / silica content. Manipulating it, it felt more solid than 'slimy' (if that makes any sense to you). 

Lyndhurst stone sample

I had gathered two similar sized pieces of stone. The one used for the CAMELOT test was roughly 6 cm thick, 7 cm wide, on its highest point 8 cm tall. The thickness was consistent overall. (4)

Normally, the hottest part of our normal furnace build and operations is a rough oval that circles the tuyere. This extends roughly 10 cm to either side, 10 cm below and 15 cm above the centre of the tuyere. A ceramic tube tuyere was used for this smelt. (5)

Outside, Tuyere in place. Stone L / Clay R

Interior view (before tuyere installed). Clay (upper) is more obvious here.

You can see here that this test may not be quite as conclusive as it might be, as the two samples are placed just outside, and below, the 'hot spot' described above.

The surrounding wall material was the standard mix of high temperature clay / course sand / shredded horse manure. 

View of the interior of the furnace - cleared after the full smelt.

- In the image above, you can see how the tuyere has eroded back towards the furnace wall. 

- The stone sample shows less reduction than the regular furnace wall material that surrounded it originally.

- There is a bit more erosion to the sample clay than the regular wall material. 

The addition of sand and organics to the standard wall material mix is done specifically to reduce erosion and the effects of high temperatures. This does suggest that the Lyndhurst clay would prove effective for furnace construction.

During dismantling - The slag attached to the stone, and heat effects clearly seen.

The stone itself showed almost no damage at all - at least on a single smelt sequence. Again this suggests that the locally available stone would prove resistance to damage and effective for at least bloomery furnace construction.

Conclusion:

At least as 'proof of concept' both the clay and rock samples gathered have endured a full bloomery iron smelt, at least within the dynamics of limited size and specific position. 

Ideally this limited test should be followed up with full builds, clay cylinder and stone block. 

1) The report on my observations of the dig - and my interpretation of the ground at Lyndhurst is still pending!
The excavations (test pits really) I helped with were on the west bank - bloomery iron furnace side.
One of the problems with close inspection of the original furnace construction is that the site of the bloomery furnace has been reused for two large scale commercial operations since. First was a flour mill, which involved the building of a more massive stone walled structure, which appears to have been constructed on top of the remains of the iron furnace. (This itself subjected by a major fire in 1811, which destroyed the entire complex.) Later there was a lumber mill constructed over the remains of the abandoned grist mill. This lumber mill was in operation into at least the 1950's, when another major fire destroyed that operation. Considerable earth fill has been added over each of these sequences in an effort to level the ground. The test pit that appeared to extend down to the level of the bloomery furnace was a good 2 metres deep below modern ground level.

2) This is apparent when you consider the wide variation of furnace builds seen throughout the Norse world. Although the slag tapping, 'short shaft' design is fairly constant, the builds range from clay (Denmark), stone slab / block (Norway), to grass sod (Iceland). See the extensive experimental series.

3) The working temperatures inside an bloomery furnace are in the 1150 - 1250 C range (or higher in a cast iron producing blast furnace). Limestones will decompose into lime (CaO + CO2) at about 900 C. You * might * be able to work around this by either using massive thickness and allowing for aggressive erosion, or using a sacrificial clay liner. (Note that is is very offhand - I have no direct experience here!)

4) I freely admit that my knowledge of stone types is limited at best!
The stones gathered appeared to be some metamorphic type.
(DARC does include a professional geologist, and I need to get him to examine the rock used.)

5) This with a fairly durable ceramic or the very fixed copper tuyeres in standard use. Tuyere set 5 cm proud of the inner surface, roughly 20 degrees down. Important is that this is also with a high volume air blast.
Past experiments has proven changing these settings can dramatically change the amount of erosion to wall materials.

Telling People What they WANT - 'Making a (kitchen) Knife

I am wondering if you would run a session or private session on how to make a kitchen knife for 1-2 people.  I would like to make a knife that I could use daily.

I am getting requests like this a couple of times a week. So I freely admit that I have developed 'a bit of an attitude' about this...

'Forged in Fire' is completely fake, or at minimum extremely inaccurate and grossly misleading. (1)

Attempting to make something that vaguely looks like a knife is not at all the same as making a truly functional knife.

Forging a blade requires considerable hammer control. Control is only possible to achieve through practice.
Working with actual blade effective alloys requires good control of temperatures. Again equals experience (practice).
This means basically the results for a first time effort are likely to be poor.

After forging, shaping and polishing both takes considerable time - and considerable equipment. (2)

Two large blades, forged and ready for grinding & polishing.

You can switch one for the other (very expensive long belt sander instead of hours with a hand file).
I am not equipped with multiple polishing work stations. (3)

Remember there are three (or four) individual, separate skill sets and equipment requirements to actually make a finished knife :
Forge
Polish
Handle
(Scabbard)

'Gut Ripper' - 1979 (one of my first knives). All hand polished = 50 + hours

Kitchen knives, especially, are more complex shapes, and the demands of use require far better levels of skill. Often the use of more difficult to control specialised metal alloys.


I do not just 'market' courses.
Others do not share this opinion, and so are willing to merely give people 'what they want' - NOT 'what is true'.
(See a recent commentary here about 'axe making courses'.)

My concern is for actual learning.
To that end I offer a selection of programs that I know I can instruct effectively, have invested considerable to equip correctly, and outline what any individual should be able to achieve inside the time limit. 
I bring over 35 years teaching experience in a workshop setting to these assessments.

Consider how the 'Build a Zombie Killer' program is described...
- This program intentionally described as for 'fun' / not a 'technical' instruction
Against the description for 'Basic Bladesmithing'...
- A blade forging program, with 'basic forge skills' as a minimum requirement

In actual fact I would consider 'Making a Kitchen Knife' a third level program.
I will strongly advise you to only have limited expectations on the results you should expect. This will vary considerably depending on what hand skills you bring. 


I know Jeff Helms offers a one week long program via Haliburton College 'make a knife', offered over the summer.
Jeff is an excellent artisan, and a very good teacher. Expect considerable hand polishing work (the College is well equipped with forges, but has virtually no polishing equipment).

I know that David Robertson will sometimes undertake a two day 'make a blade' program for untrained students. You would have to contact him for details and availability. 
I do recommend David as an excellent teacher. (I have worked with David for about 35 years, and have taught programs together in the past.)







1) I have made several commentaries about 'Forged in Fire'. It has become the bane of all ethical metalworking instructors, as there is little Truth in 'Reality Television'.
'Forged in Fire ?' : October 2015
'Forged in Fire'- not this professional! : March 2017


2) I have made a few knives, but I don't consider myself a full time bladesmith. 
- For me to forge out the basic shape for a knife size will take me roughly 30 - 60 minutes, depending on profile and size.
- The annealing step takes overnight.
- Surface grinding, profiling, polishing typically takes me 2 - 4 hours. (see below)
- Hardening, surface polish, Tempering, final polishing, typically adds another hour.
- Hilting is extremely variable, depending on what fittings are added, the materials selected, what shapes and size is involved. Expect multiple hours at minimum.
- Scabbard? (I personally am not much of a leather worker, and typically do not provide scabbards - just simple leather 'keepers'.)


Note that I differentiate between :
Bladesmiths : those who forge bars into the blade blanks first. This allows for considerable freedom of design.
Knifemakers : those who grind out blade blanks from simple rectangular bars. Often don't undertake their own heat treating. This results in simple (often standardised) shapes.
(Watch 'Forged in Fire' - you can always tell the difference.)


3) What they are using for grinding and polishing on 'Forged In Fire' ??

This is a currently available 'knife grinder' - actually a long belt, high speed sander:
- 2 HP motor
- electronic variable speed control
- 2 x 72 inch belts
- front vertical plate
- large contact wheel (note the FiF units have a larger rubber wheel, additional cost)
Rough cost = $ 2000+ US

3) As I do not normally offer any 'knifemaking' programs (ie - bar to finished knife), I only have my own personal equipment:
- angle grinders with grinding disk (possible use of flap sanding disk)
- one bench grinder, 1/2 HP (I have a second 1/3 HP I could set up)
- one 6 x 48 sander, retrofitted with a 2 x speed 3/4 HP motor
- one 2 x 72 sander, 2 HP motor (which I do not provide to students)

"Americas Lost Vikings" Iron Smelt sequence

I had undertaken an iron smelt last October for Arrow Media (of the UK) for their series America's Lost Vikings.

This was all related to a specific object, a small spear head in the collection of the Wayne County Museum, Lyons, New York. (1)

'Charles Point' Spearhead : Length = 9 inches (+)

Now, I had been asked by the Producers not to release any information about this undertaking until the airing date for the segment I would be included in. This became part of episode three, later given the title 'War in the New World'. (2)

There was considerable back and forth, in considerable detail, on my research into bloomery iron smelting, Viking Age making and working technologies, Norse weapons, especially spears, and 'Vinland' in general. (3)

For this specific commentary, I will be limiting my critique to the only the depiction of the iron smelting itself :

during the smelt

Some technical aspects of the iron smelt :

Furnace Type - standard 'Norse short shaft' on stone plinth
Wall Material - clay / sand / horse manure mix
Measurements - ID = 27 cm / total height 73 cm
Tuyere - standard copper
Placement - 21 cm above base, 5 cm proud, 22 degrees down angle
Air System - standard blower, 1100 LpM (via scale)

Total charcoal consumed - about 60 kg
Base Set - 1.2 kg slag added
Ore type - Taconite (5 kg) / 'DD1A' (red oxide with 10% added forge scale)
Total ore used - 30 kg
Total time - 6 hours (plus burn down and extraction time)
Bloom weight - 8.5 kg
Yield - 28%

Supporting Team : David Robertson & Neil Peterson (seen but not named)

This is just the 10 minute segment that features the iron smelt itself.

Currently the full episode is available on YouTube. (4)

Leaving the edit method aside. (I personally hate that jumpy film technique - and this was not how it was shot originally.)

There is too much information that was filmed, but was not included.
There was totally artificial 'drama' created.

ONE : INACCURATE DESCRIPTIONS

There is inclusion of a diagram, intended to picture what happens inside the furnace.
It is wrong - and based on illustrations since proven to be incorrect. Including extensively in my own writings, presentations - and information sent to the Producers, and as described during that long day itself.

extracted from about minute 6

- The internal structure of the furnace as a 'layer cake' is simply not the actual case. I had explained the real mechanism in some detail. In actual fact, the reduction chemistry is a gas reaction, so the ideal (and real) is an even distribution of ore evenly through the charcoal mass.
(The theory illustrated is based on incorrectly understood descriptions of African 'tall shaft' furnaces, long discredited.)
- Why are two air intakes shown? And no tuyeres? And shown as flat lines? And shown right on the base of the furnace? This certainly does not illustrate the furnace that was built. Or Viking Age furnaces of any kind. Or the diagrams I provided before the filming?
(This appears to be a cross section of a Roman 'passive draw' furnace - which typically are three to four times the physical size of what was used.)
- That is not were the bloom forms. Its not the right shape. It is most certainly not an illustration of what the real filming shows happened!
- Where is the slag? Above the bloom? Again, this is simply not what happens in the real working furnace.

NONE of this agrees with the (extensive) descriptions I gave, both during the initial research, and during the actual day of the smelt.
NONE of this agrees with what is actually seen in the filming sequence itself. (5)

TWO : DISTORTION for DRAMA

That slag tap.
It is so NOT what actually happened.
You have to consider my personality, my nature as a teacher.
I had two archaeologists, who had never seen an iron smelt before. The tone of the whole day was as an example of the real operation of a bloomery iron furnace. I was acting as a 'known expert'. Nothing was 'faked'. I cautioned the Producers extensively that the smelt was a linear process, which could not be modified in any significant way. What they would see would be what actually happened on the day. There would be no halts. There would be no 're-do'.
'Things have gone badly wrong. Our experiment is about to fail'
Do you notice that I am taking time to describe the situation inside the furnace, how I know that, what it means, what I have to do? Must not be that much of a panic.
You notice that all the comments about frantic action, failing experiments - all are coming from the hosts. Shot away from the activity at the furnace? Set up to anchor a commercial break?
All to add 'drama' to what was in fact a wonderfully even and controlled iron smelt. Honestly, at the time I was actually concerned that there would not be ANY slag tapping required. I wanted to have Mike and Blue experience this aspect, and worried they might not see it. The 'frantic' was because the two, without experience (of course) were moving just too cautiously and too slow. There was need for a slag tap. This was a slag tapping furnace after all! (6)

THREE : MAKING STUFF UP

'If there is too much exposure to Oxygen, it will contaminate the Iron'
Heard during the sequence when we are doing the initial compaction and cutting.
Say WHAT?
Who had that fit of imagination?
The need for speed is that the iron bloom quickly cools below effective working temperatures when it is pulled from the furnace. Only.
That statement is a total fabrication.

'One bloom = one sword'
I got asked specifically about this. This is NOT what I told the Producers.
I had actually converted my long reply in detail to my estimate on how much workable iron this smelt had produced into an earlier blog posting.
My actual reply ?
Estimate two or three - depending on quality of the blades

'Viking Age swords have a blood groove'
Aw come ON...
This is just plain pop culture trash. No one who actually knows anything at all about weapons design, especially historic weapons, knows this is just plain stupid.
The shallow groove down the centre of a long blade is called a fuller.
The purpose is two fold:
a) it reduces the volume of metal, so reduces the overall weight of the blade
b) it changes the cross section from a diamond to a more complex shape --]---[-- , structurally strengthening the blade

Someplace in the edit process, the Producers (someone) decided to purposefully dumb down the whole content. Information was distorted for dramatic effect.
Entertainment totally dominated over content.

From such a good beginning, the final result?


1) Expect a fuller commentary to come about this object, and my own assessment of what it may actually represent.

2) I hardly know where to start here!
I have to say that the end product as broadcast is most definitely NOT what I expected!
- I had initially found the researchers at Arrow to be intelligent, undertook background reading I suggested, and both appeared to understand those materials and ask relevant questions.
- Both 'hosts', Mike and Blue, I found to be engaged and truly interested. They both were more than willing to get in and get involved in the tasks required. (The by-play and hesitancy seen on screen was largely made up for the camera.) Both were actually had at least a basic understanding of Viking Age Norse history.
- The camera crew where extremely professional and easy to work with. Almost everything was shot exactly as it happened - in real (working) time.
The final broadcast version was not what I had been lead to expect as the tone of the series.

3) What I personally consider the major flaw in the whole premise of the series as presented :
Vinland is not a single point location
The term 'Vinland' was used by Leif Erikson quite specifically to label a large region.
It should be compared to 'Iceland', or his father Erik's label of 'Greenland'.
So, to the people who gave the name, it was always intended to refer to 'That area west of Greenland, laying south of Helluland and Markland. (You do note the use of other regional names on this list?)
To the Norse, the piece of ground at L'Anse aux Meadows was specifically named 'Leifsburdir', meaning 'Lief's Houses'.

4) The included segment here is 10 minutes of the total 45 minutes of the episode, running roughly from 15 - 25 minute marks. I freely admit that I am skating on thin ice here.
I admit than have not been given permission to publish this sequence.
This segment has been drastically reduced in both quality and size. It also represents a bit less than 1/4 of the total. I also freely admit that this is more than the standard 'reproduce 10%' allowed for commentaries.

The YouTube link is to some (unknown to me) private individual who obviously viewed and recorded the full episode. There may be blocks based on your personal location (I saw someone say it was blocked for view inside the USA?) The video may also be removed at any point.
(I don't have commercial TV here, and would not have seen my own sequence if not for this placement on YouTube!)

I may undertake an additional commentary about Real vs 'Reality Television' - as those who follow these pieces may note a bit of a trend towards this topic of late.

5) All I can say is 'what the...'
Other than laziness or plain refusal to use fact - I can see absolutely no reason for this illustration. The Producers obviously instructed someone to draw these graphics. They obviously allowed the wrong source materials to be used - when they clearly had the correct information available.
I personally can see absolutely no reason what so ever that this would be undertaken. Did no one see that they were presenting information that contradicted their own filming? (You do understand the link between accuracy and 'authority'?)

6) My concern here is largely personal - and based on reputation.
I get introduced as 'one of the few in the world'. Ok - most certainly the only in Canada, and honestly one of the few in North America. But 'in the world'? (Apologies to my friends in Denmark especially!)
But seriously - this was almost a text book example of an ideal bloomery iron smelt. That is the proof of ability.

Telling People what they WANT : 'Make an Axe'

I came across your webpage and I was wondering if I could arrange for a private session so that I can build an axe. ... I plan on building the handle ahead of time, so I was looking to just build the blade/head with your assistance. I likely will bring someone with me as I understand it can be a two person job.

Recent e-mail to the Wareham Forge 
The following adapted from / suggested by my reply :


No, not realistically
I have a suite of programs I offer. (A total of 12 different programs)
The content is based on what I consider reasonable objectives for students.
Also what I am equipped to undertake.
Filtered by what skills and knowledge I am interested (and able) to teach.
I do not offer a one day axe making program.


So - unpacking the questions embedded above?

Forged Replicas by the Wareham Forge : Norse trimming axe (UL) / Hudson Bay trade axe (modified commercial) (UR) / Norse tool axe (C) / Artifact French trade axe (LL)

I've made a few axes over the decades.
There are a number of commentaries related to axe making and specifically Viking Age axes available here as past blog postings :





Norse Woodworking Axes
VA Ship Tools - Adze & Broadaxe
Jim Austin - Axe Making Tutorial
French Trade Axe from Bloom Iron
Ship Tools - Adze / Broadaxe




Loosely, there are two broad ways an axe can be made:

Viking Age Dejbejerg Axe replica

A solid block of iron can be punched on one end to create the eye.
The other end is then flattened out to a long taper.
There may be a small piece of hard steel forge welded to this taper for the edge. This may be done by cutting a slot into the end and inserting, or lap welding the piece to one side

Norse fine tool axe

A long narrow strip of iron can be folded over, then one end is forged welded together, leaving a gap at the fold to create the eye.
There most typically is a piece of steel inserted to the far end before the weld to create the cutting edge. (In the image above, you can see the colour shift.)

You can see how both these different construction methods result in quite distinctive shapes to both the peen end (heavy block when punched) the transition from sides of the eye to body (2 x thick typically for folded).
In most cases the shape of the punched eye is also different, with punched tending to round or oval, with folded to box or tear drop.

French Trade Axe - in process

Of course, a more complex method is to first profile a rectangular strip before it is folded over and welded. (Most Viking Age axes actually appear to use variations of this method.)

Over history, the method used at a particular time and place, with the resulting 'ideal' shape of the finished axe, is so specific that the shape of axes can often be used as a rough dating method.

Norse tool axes - for L'Anse aux Meadows NHSC

Note that my general prices for a properly forged axe head start at about $300.
This for a block of mild steel, profiled, folded, then forge welded with a carbon steel insert for the cutting edge, drawn to shape, ground and polished to sharp, heat treated correctly.
I would normally spread this heavy work over at least two working days, more realistically like three. Remember that I've made more than one of these. I have made the investment in a number of specialized tools, especially heavy powered tools (air hammer), but I'm also getting to be an 'old guy'.)


There is an individual who does offer what is described as 'one day axe making'. (The content of the e-mail does indicate that this is the point of comparison. 1)

So - What do * I * think is possible?
For a totally untrained individual, within a standard 9 to 5 workshop session?


I do not attempt to instruct forge welding as an (absolute) beginner's technique.
- You need to be able to accurately judge temperature through colour.
- You need to be able to quickly and accurately place hammer strokes.
- You have to accurately apply the correct amount of force through each hammer stroke.
I consider all of these elements only possible through practice. No practice = no control = bad results.
So folded construction is out, as is the addition of any carbon steel insert edges.

It might prove possible to start with a block, pre-drilled with a pilot hole (how many drill presses do you imagine I have?). Students would drift that hole open for the eye (would require one set of drifts per student of course). Then the other end of the block tapered and flattened to some kind of edge.
I will say however that this is heavy forging work. In untrained hands, the chance for incorrect hammer use vastly increases (Especially as most certainly attempting this work in a single day suggests rushing, into excessive physical fatigue.)
Honestly, I would not rate the probability of good results, or even finishing the work, very high.

What if you started with the eye pre-punched, the block ready to flatten to an edge?

Hammer into Axe - Black Bear Forge (see the video)

It could prove possible for someone with no forge experience to take a commercial ball peen hammer (already is half decent steel, has a prepared eye) and re-forge it down into a simple 'pipe hawk' shape. You could find lots of samples of this standard method on the internet.
This would likely be achievable for an untrained hand in a workshop day.




Another point from the e-mail above?
The handle is fitted to the head - not the other way around. You could do some previous work by splitting out the rough length, shaping it to oval with axe / draw knife. But before you know the size and shape of the actual eye - you can't really get much beyond a very approximate shape - or it simply will not fit correctly.
If you were making standardized axe head blanks (like using pre-made, standardized dies on an air hammer - see above) you could have rough blanks prepared in advance. Of course this is all woodworking - not blacksmithing, anyway.


As you can see on the web site, a 'private session' one day (9 to 5 - lunch) runs $300+.  http://www.warehamforge.ca/TRAINING/train.html
For the hammer head to hawk project, expect an additional $30+ each for the starting hammer blank (another $25+ each for the handle blanks).
(Check current prices at Princess Auto)





1) I quite specifically am NOT identifying this individual - for a number of reasons:
- Looking at the related published materials, it is hard to actually determine what this 'one day axe' actually entails.
I think what this really is : one day bash an edge thin. Given the space and activities pictured, I believe he is providing students with a pre made blank (rough profile with eye already made) and students thin out the block on the edge side. This is a bit more complex than taking a bar and grinding an angle on it - but not much. 
- The class sizes indicated are much, much larger than my own (considerable) personal teaching experience suggests are either effective or able to control. 
(In my own programs six is the maximum, and many specialized skills are limited to four, sometimes only two, students. Forge welding is limited to two students.)
- Clearly, anyone offering a specific 'object' workshop, has to have invested considerable time, expense and effort into specialized tools - and enough of these tools to equip the intended class size.  (An excellent example is this video of Gransfors commercial axe forging)
- I personally consider there is another element at play here 'Give them what they WANT - not what is TRUE'.