ARISTOTLE FURNACE - Workshop at SSW

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NEW Course!

Tuesday, 8th 2014f July, 2014

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From Turf to Tools - The Aristotle Furnace
Artisan Blacksmith Darrell Markewitz will be leading a weekend course in bloomery iron production. Darrell, joining us from Canada for the Turf to Tools project, has over 35 years experience as an artisan blacksmith, with particular experience in ancient bloomery and forge processes.
This course is for anyone interested in metal as material, as well as those studying historic ironworking processes – in production or research. All participants will find the Aristotle a quick 'table top' method for producing small amounts of useful metal. The 'Aristotle Furnace' is a small charcoal furnace that will convert any kind of iron into a cake of metal with a set carbon content. In effect it allows conversion of scrap into a tool making material. The resulting 'puck' has the physical texture of a bloomery iron, but at a carbon level suitable for cutting blades.

In this two day / 16 hour-long hands on workshop, participants will first build, then operate their own furnace. A number of roughly 500 gm 'pucks' of metal will be made, experimenting with different starting materials. Finally, using a coal forge, individual pucks can be consolidated into working bars. If time permits, a small Iron Age style chisel or blade can be rough forged.

The course is open to all regardless of previous experience or ability, although those with background or knowledge in metal processes will definitely gain an invaluable experience – not to mention a new table top furnace that you can take away with you. All materials are included in the course fee, and participants will be provided with all the tools and safety equipment needed. Students must come dressed in long pants, all clothing of natural fibres (cotton, wool) only. Boots of some sort are required, ideally above ankle height.
Your instructor is Darrell Markewitz. He is a professional artisan blacksmith from Ontario, Canada, with over 35 years experience at the forge. A major area of his work has been with objects and processes from the Viking Age. He designed, created and implemented the living history program at L'Anse aux Meadows NHSC for Parks Canada, ongoing since 1996. His involvement with Ancient and Early Medieval bloomery iron smelting started in 2001, and he has undertaken over 55 experimental smelts since then. He is one of the founding members (and instigators) of the Early Iron movement in North America. Find out more via his web site www.warehamforge.ca
Title:   Aristotle Furnance
Date:  10am - 6pm Saturday 30 August to Sunday 31 August
Venue: Scottish Sculpture Workshop
Price: £180
To Book: please emaily Emily@ssw.org.uk or call 01464 861372

Turf to Tools - Official Release!

From Turf to Tools – Rhynie Man Axe

July 17, 2014 · by sswlumsden · in Artists, Community, Events, News, Opportunities, SSW Courses. ·

From Turf to Tools is an ongoing investigation in to landscape, material and craft, inspired by local archeological investigations in Rhynie, Aberdeenshire.
From 11-24th August, the collaboration of Scottish Sculpture Workshop artist Eden Jolly and master blacksmith Darrell Markewitz, with Dr. Gordon Noble, archeologist at University of Aberdeen, will seek to recreate a ceremonial axe – as seen on the Rhynie Man standing stone – through smelting and forging locally sourced materials.
The Rhynie Man stone is dated to roughly 700 AD, and shows a man carrying what looks to be a ceremonial axe, the type of which was used to sacrifice cattle – part of an early Pictish King’s role as a religious as well as a secular leader. During the excavations carried out in 2013, a pendent depicting the axe was found, along with metal-working tongs. This find led to the initial bloomery smelt held in Rhynie last summer, and further dialogue between Scottish Sculpture Workshop and the Rhynie investigations.

Throughout the two weeks in August, the team will be attempting to create the closest possible historical model of a bloomery furnace – this is the extracting of workable metal from raw materials. This ‘bloom’ will then be forged to create a replica of the Rhynie Man axe. Although there is little information available regarding how these complex processes were undertaken at the time, looking to other excavation sites, such as Culduthel near Inverness, helps establish ideas regarding how it might have worked.
For the duration of the project, the team will be joined by a number of artists, archeologists, craftspeople and students in a cross-discipline discussion regarding landscape, materials, resources and history. Of particular interest is the sourcing of a local iron ore – one suggestion being the rare Macaulayitye found at Bennachie. This is the only known source of Macaulayite in the world, and is proposed to be a similar material to that found on Mars. We are actively looking for input from all areas, and welcome any information or skills that are available.
The project will culminate in a public open forum during the weekend of 22nd to 24th of August, with demonstrations as well as a sharing of knowledge, skills and ideas. This forum will attempt to address a number of questions regarding both the specifics of the process, as well as how a specific archeological prototype might provide valuable insights into a historical period.
From Turf to Tools is offers an opportunity for skill-exchange and training, and as part of this we are also running a two-day course of 30th and 31st of August, lead my Darrell Markewitz, for those looking to gain some direct hands on experience. Titled ‘Aristotle Furnace’ the workshop is to make a tabletop furnace, capable of producing workable iron. The course costs £180 and includes all materials, as well as your own furnace that you can take away with you.

For further information please contact the SSW office on 01464 861372, or email emily@ssw.org.uk

This article copied directly from the SSW web site 

a bit about HAMMERS

(edited from an e-mail)

Although you can make due with almost anything, precision requires control, and hammers are pretty individual. This is primarily due to the dynamics of the human body. Those who have seen me know I am tall, thin and relatively light framed (5 ft 11 / 155 lbs). This usually means a more balanced head shape, and a longer, typically thinner handle.

The weights are also important. For most lighter weight forging, a 800 gm (1 1/2 lb) is going to be most useful (and desirable). For the heavier work (really much over 1/2 square bar) a 1000 gm (2  lb) is going be required.
I personally find a 1.5 kg (2 lb) a bit heavy, although if the design is good, can manage it with care.
' Impact energy of a stroke is mass times velocity '. Leaving mass penetration aside, with my lighter frame, I tend to use a lighter hammer moving faster, with more stokes and the ability for better control. (I have seen over the years, too many people, especially the hobby smith, will use much too heavy a hammer. Then complain that their elbow hurts! ' It don't matter how hard you can hit - if you miss! ' )


Typically, any smith will have one hammer which is their primary. Then a couple more they use for more specialized forming. And then a pile of hammers they virtually NEVER use. 
A useful piece of advise : Don't rush out and buy an expensive hammer just as you start. Best is to try a number of different profiles, to find one that best suits you personally., * Then * spend the money for what will likely become your primary forging hammer. (A good quality hammer can easily run $75 +) There is no significant reason not to just purchase 'cheaper' hammers - for those you only rarely use anyway.


Check and see if you have any local sources for 'cheap' hammers. Surplus stores and 'low end tool' places can often be a good source.  We can get some square faced cross peens in Ontario that come in from China. While I am * not * in favour of Chinese tools in general, these run less than $10 around here and are acceptable quality, especially as 'seldom used' hammers. 'Twin Swallows' is one brand name.

 

 
'Historic - Square'
These are both Chinese square faces, in the classic cross peen shape
These used to come with very poor quality wooden handles (which you basically want to replace with proper ash handles). Then for a while they came with fibreglass as seen. The fibreglass is not ideal, but actually better than what ever crap wood they once used. Lately, these come with * plastic * handles, which is virtually impossible to use. (Every stroke seems to bounce the return into a different direction - very difficult to control!) Balance that against the cost, $8 here last I bought one.
The heads are made of a basic quality mid carbon steel.
I will buy these, take off the handles *, and re-forge the heads to make other shapes. The second hammer is one such, re-shaped to replicate the shape of hammer found in the Mastermyr tool find (Gotland, Norse, c 1150)

'Round Face'
Here are two 'antique' hammers, one at 1 1/2, the other at 2 lbs. This style was common here for farriers in the early 20th. The weight is fairly central to the handle, and they are reasonably evenly balanced, front to rear. The faces are fairly wide, and typically the peen is quite broad. You do have to keep your eyes open, but around here at least there is a fairly good supply of these. Typical prices are about $20 - $25 each.

'1000'
This is a 1000 gm size (for comparison), with a kind of 'semi octagonal' head shape. The peen is medium to sharp. I find this specific hammer quite balanced and easy to control. I got a number of these, an end of lot from a closing factory here in Eastern Ontario. 

'Favourite'
This is  * my * hammer. I've been told it is a German Engineer's Hammer, produced in the inter war period. I have only ever seen one other one in all my years smithing and travelling. This is an 800 gm, I must do at least 80 % of my forge work with this hammer - and have been using it some 30 plus years at this point. (Surprise is that I got this at a yard sale for all of $8, completely at random - just as I was starting to get serious about blacksmithing.)




* Home Hardware (here in Canada) sells a " 16" Blacksmith's Hammer " handle. Get your local to check their inventory, they likely will have to order them in for you. (And keep a spare in the shop!) Cost is about $7. These are an excellent straight grained ash or hicory. They have the required oval eye (not square like a carpenter's hammer). Do remove the varnish (prevents blisters) and re- shape the handle to thin it out below the head. (Better to break a handle than put extra shock into your elbow!) You can see I wrap some hockey tape around the shaft below the eye - this is to protect the wood if I miss when forging elaborate curves around the far side of the horn. (We all miss * sometimes * !)

Turf to Tools - OUTLINE

This is the draft working schedule for the Turf to Tools project at the Scottish Sculpture Workshop, Lumsden Scotland, in August:

	SATURDAY	SUNDAY	MONDAY	TUESDAY	WEDENSDAY	THURSDAY	FRIDAY
	9	10	11	12	13	14	15
Available
AM	work site organize	furnace build	SMELT 1	clear ?	CONSOLODATE 1	BLOOM - BAR 1	materials prep
PM	smelt tool build	materials prep	SMELT 1	forge build ?	BLOOM - BAR 1	AXE 1	clear ?
Note			furnace test			mild steel axe	furnace repairs?
	16	17	18	19	20	21	22
Available							Crannog Centre?
AM	SMELT 2	CONSOLODATE 2	clear ?	AXE 2	spare ?	ARISTOTLE build	CC lecture ?
PM	SMELT 2	BLOOM - BAR 2	BLOOM - BAR 2	AXE 2	spare ?	ARISTOTLE fire	materials prep
Note	ore test			bloomery axe
	23	24	25	26	27	28	29
Available	Murray
AM	SMELT 3	CONSOLODATE demo
PM	SMELT 3	AXE demo
Note	historic ?
	30	31	1	2	3	4	5
Available
AM	ARISTOTLE COURSE	ARISTOTLE COURSE
PM	ARISTOTLE COURSE	ARISTOTLE COURSE
Note

Pictish Iron : Bloom to Bar

Continuing the commentary related to the 'Turf to Tools' project coming up from August 9 - 24 at the Scottish Sculpture Workshop.

An initial test run of a Pictish Late Iron Age bloomery iron smelting furnace was made in Wareham on June 14 :

Kelly Probyn-Smith holding the freshly extracted bloom mass

The data from the smelt:
Burn rate - average 10 - 11 minutes per 1.9 kg charcoal bucket measure
Total ore added - 31.1 kg (28.3 kg 'dry' weight)
Ore additions range from 1 - 2.5 kg per bucket
Total charcoal used - 61 kg
Total time - 1:15 for preheat / 5:30 main sequence to extraction
Finished bloom weight - 5.2 kg
Yield - 18% (from dry ore weight)

Resulting Bloom - only partially scored

The important next step in having usable iron is compacting the spongy and slag containing bloom down into a dense (and crack free!) working bar for the blacksmith. This is a step often overlooked by the archaeologist, and poorly understood and researched.

The next day, we were joined by David Robertson and one of his students (Mike). The session was to at least start the process of compacting the bloom towards a working bar. Using my hydraulic press, the rough mass was compacted (at welding heat) down to a flat plate about 5 cm thick. This plate was then cut into four roughly pie shaped pieces. At this point a more accurate estimate of carbon content via spark test could be made of the interior. The estimated result was a surprising .60 to .70 carbon - a tool making material.
Both David and Mike worked at compressing their quarter pieces down towards a possible block, to their credit working all hand tools (in a coal forge).

One of the resulting quarter sections

A couple of days later, I took the section seen above and forged it down to at least a first stage 'block'. The piece I started with weighed 1278 gm.
I had the services of my 50 lb Robertson air hammer, plus my 30 ton hydraulic press. All heats via my large coal forge (bottom blast). Hand hammer was a 1000 gm.

The full working cycle (number of heats) :

(compress surfaces on hydraulic press, at welding X 3)
(cut in half, then to quarters on hydraulic press X 2)

Light welding by hand, surfaces and edges X 6
Attempt to work down edges on air hammer (not effective) at welding X 2
Compress on hydraulic press to brick at welding X 3
Work 4 sides to block on air hammer at welding X 2
Weld back both ends by hand X 2
Pull to billet, starting on side surfaces at welding on air hammer X 2
Flux and weld by hand over centre flaws on top and bottom X 2
Draw to even billet on air hammer X 1
Clean up to final shape by hand X 2

Near the start, after edges were welded down by hand

Total heat cycles - 21 (+5)
Heat cycles at 'welding' - 19 (+3)
Cycles by hand - 12
Cycles using press or air hammer - 9 (+5) *
Total elapsed time - 2 1/2 hours *

* These two numbers are significant in relating the use of modern powered equipment to historic practice, working with human muscles alone. If strikers using sledges were employed, there would still certainly be some increase in number of working cycles / time expended. (Guestimate - increase by 30 % or more.) Starting with a 1.2 kg mass, it certainly would be possible for an individual to have worked these processes alone. (Guestimate - increase by x 4 - x 6 work cycles)

Resulting 'block', top and bottom surfaces

The 'block' at this point is still not completely refined. At this point the weight is 957 gm. Size is 16 x 4.5 x 2 cm. You can see that there is a major crack that runs into the bottom side about the mid line, about 3 mm deep.
The next step will be cutting along the crack, then adjusting the two pieces to the same width and length. At that point they will be welded up again, then drawn out slightly to ensure there are no more major flaws.

At this point:
Bloom to block loss = 25%
Ore to block yield = 13.5%

Hopefully the resulting billet will be compacted concisely enough that it can then go on to the final sequence - forging an actual replica of the axe-hammer. The billet is roughly the right size / volume for making one of these  objects.

One of the important observations here is the huge amount of effort - and overall losses, involved in producing a working bar for the blacksmith's hands in historic times. Besides the obvious use of power tools, an important difference is the use of rock coal instead of the historic charcoal as the fuel.

This should make us think differently about the value of those objects created by ancient smiths!

For more details on the Turf to Tools project (several photo essays and commentaries) :
http://warehamforgeblog.blogspot.ca/2014/06/scottish-dark-ages-iron-smelt.html
http://warehamforgeblog.blogspot.ca/2014/05/some-considerations-on-iron-ore-for.html
http://warehamforgeblog.blogspot.ca/2014/06/pictish-late-iron-age-smelt-overview.html

For information on the Scottish Sculpture Workshop
http://www.ssw.org.uk/