Saturday, November 16, 2019

Aquarium

Kelly took me to the Ripley's Aquarium in Toronto, Thursday.
Here is some of the take...

'Traffic' : A large cylindrical tank of Alewives (?), endlessly swimming in circles.
A large Atlantic Lobster (about 24 inches?), tucked back between rocks.
Lion Fish, head on view.
Jellyfish - dramatically lit.

I took a good series of reference images for the Lion Fish against an idea that struck me for kinetic sculpture.
Another series for Kelly of the Jellyfish, again for potential future sculpture.

We spent a good long time near the start of the long walk through (under) the huge topical reef tank. This pool has a snaking tunnel running through it, which lets you see the resident fish up close as they swim their lazy circles.
I did wonder how the cluster of sharks (looked to be a dozen, of various species), some up to a good 8 feet long, coped with the density of fish and spaces. These are sharks after all (not the brightest of creatures), but in the wild have a lot more roaming space most certainly.

It was charming to see the youngest children, obviously enthralled with how close they were to the animals. And honestly (given my recent experiences) encouraged by those parents who were enthusiastically giving their children what was certainly to be a formative experience.

Monday, November 11, 2019

Remembrance Day - 2019

I'm floundering a bit today.
Remembrance Day is always hard for me. I served in the Canadian Army Reserves, 1972 - 1976. I had signed up (underage by about two months), roughly the same week as the Fall of Saigon in Vietnam. My own family economics made television use both limited and spotty. So I personally do not remember seeing 'the War in the living room'. I did end up having instructors who had served in Vietnam, and most certainly a certain attitude towards combat, which I never have directly experienced, was instilled. Anyone who knows me is aware of how deeply those four years of evenings, weekends and summers effected my developing character as a young adult.

Of my two closest and ancient friends, both had experience on the sharp end. One first during peace keeping in Egypt, then later during drug interdiction in Mexico. The other through two tours with the 101 in Vietnam, and later peace keeping in Cyprus. Through these two, and other associated friends, I have met (often over drinks) a number of men (mainly) who were then, or had been, serving military, in a number of national uniforms. Often being the 'wannabe' at the table, I have tried to listen and learn from the experiences of others. 
One of those friends, although still close in spirit, now lives on the other end of the country. We swap the odd e-mail, keep in tough through Facebook notes. The other has faded back into himself, withdrawn from most all the world and attempts in communication have just failed. 'Radio Check, Over' gets nothing but a quiet static hiss...

For years and years on this day, the three of us would do our best to gather in some quiet corner, hauling out old rank badges and drinking a toast 'to absent friends'. Sometimes a propped up photo with its shot glass holding it up. Over the years, the circle had changed, other 'true spirits' dropping in, our out, as situation allowed. 

But this year, the darkness will only be held back by a single candle. 
And for myself, the last few months have seen the darkness certainly gathering strength.

Artist Unknown - Image stolen from 'Wear Your Poppy with Pride'
Observing students at Laurier in Waterloo last Thursday, two things were obvious.  
  • Remembrance Day is clearly a Western / European marking. 
  • And a modern generation, who have had such limited personal experience with a 'shooting war', don't much mark it either. 
 Now, in an abstract sense, I understand this. The World Wars were massive efforts, by both military and civilian. In WWI, about 10% of the entire Canadian population were serving military. Of those some 39% were casualties (dead or wounded). Because in many rural communities, the entire population of young men would enlist, train, fight (and often die) together, this impact was devastating.
In WW2, the percentage of serving military was again roughly 10%. The number of casualties was greatly lower, here closer to 10%.
In both cases, there was a general draft / conscription of soldiers, although a great many volunteered. Since WW2, Canadian combat troops have been drawn from the (volunteer) enlisted in either the full time Regular Forces or the part time Reserves.

The Korean War had roughly 26,000 Canadians involved (during the conflict, more after as peacekeepers)
In Vietnam, the total was roughly 30,000.

Since those days, Canadian soldiers have been involved (and sometimes casualties of) many peacekeeping missions worldwide. It is often said Canadians 'invented' peacekeeping. Croatia / Bosnia and Somolia most notably.
Then the Gulf War(s) and Afghanistan.
In truth, some number of Canadian soldiers have almost been in constant overseas combat roles, to some degree, for the last 70 years.






'Lest we Forget' is more than just honouring those who were maimed or slaughtered to create the free democracy we Canadians now enjoy.

It also is about remembering the Responsibility we, as citizens, hold to ensure the next generation also has these freedoms. To be willing to undertake the often violent measures that are need, and to endure the risks involved.

It certainly is about remembering the Cost of our high words and good intentions. The very real debt we all owe to those who have been willing to place their own fragile bodies between the civilian and danger.


Never forget that contract.

Thursday, November 07, 2019

'Archaic' First Nations Copper Tools

I had been contacted by Gino Ferri of Survival in the Bush a (long) while back about a project involving First Nations copper tools. His desire was for a socketed style adze and a triangular axe blade. It should be noted that only vague descriptions of final shapes were given, so considerable background research had to be undertaken (beyond any technical production aspects).

'Etowa Mounds' Copper Axes (note thickness!)
Gino had provided me with a large pile of copper wire, which had previously had the insulation burned off. The intent here was to melt this down into plates or ingots, then use that material to form the replicas.  I had mentioned I was in the process of working up a ‘medium’ scale, propane fired, furnace base for potential bronze casting use. In the end that project was long delayed (still not really not to the production level).
Ancient copper smelting (reduction from ore) was not so different than the furnaces I regularly use for bloomery iron making. If anything, the copper furnaces are smaller, although they do work in roughly the same temperature ranges (≠ 1100 C for copper) (1). So I remain fairly confident that a modified version of our standard clay cobb build (likely a shorter shaft) fuelled with charcoal will serve to melt the scrap into a rough ingot.
But this in itself will be its own learning sequence, and sure to consume almost as much in materials as the value of the scrap on hand (2)

Royal Ontario Museum
Medium: Copper
Geography: Bedford Park, Toronto, ON
Date: 4000-1000 CE
Period: Middle - Late Archaic period
Dimensions: (not given)
Object number: HD10407
ROM-1
Medium: Native copper
Geography: Ontario, Canada
Date: 3500-2500 BC
Period: Middle Archaic (6000-2500 BC)
Dimensions: 14.1 x 8.7 x 2.7 cm
Object number: NS3664

(Images and descriptions above taken from the ROM’S on line collections data)

Note the dating for the Archaic Period ranges from 8000 - 1000 BC. The objects are being only rough dated above, by style more than C-14.
Source copper is most likely from ‘Northern Great Lakes’, but you can see even the find locations are vague in these descriptions.

As (considerably) more digging on the internet was to show, hard information on early copper working by First Nations was to prove difficult to find…

Milwaukee Public Museum

“ The Old Copper Complex, also known as the Old Copper Culture, refers to the items made by early inhabitants of the Great Lakes region during a period that spans several thousand years and covers several thousand square miles. The most conclusive evidence suggests that native copper was utilized to produce a wide variety of tools beginning in the Middle Archaic period circa 4,000 BC. The vast majority of this evidence comes from dense concentrations of Old Copper finds in eastern Wisconsin. These copper tools cover a broad range of artifact types: axes, adzes, various forms of projectile points, knives, perforators, fishhooks, and harpoons. By about 1,500 BC, artifact forms began to shift from utilitarian objects to personal ornaments, which may reflect an increase in social stratification toward the Late Archaic and Early Woodland period (Pleger 2000). While copper continued to be used in North America up until European contact, it was only used in small amounts, primarily for symbolic ornaments.
To date, there is no convincing evidence that archaic populations of the Old Copper Complex smelted copper to pour into pre-made moulds (Martin 1999). Indeed, many copper artifacts show extreme uniformity and quality, indicating a high degree of technological specialization. This has led to speculation that Old Copper Complex artisans did in fact reach the level of smelting copper ore (Neiburger 1984). “


" The socketed spud is one of the more distinctive types of Old Copper artifacts. There is a large range in size and style of these artifacts, which may indicate both the time and place of their manufacture. They would have been hafted onto a wooden handle for increased accuracy and efficiency. Nevertheless, the function of these tools was primarily for woodcarving and possibly bark stripping.(Left to Right: 2144, 11616/1487, 11812/1571, 15728/4394, 15752/4947, 11622/1487, 2176, 11838/1571) "


" Axes and wedges are somewhat similar to chisels and celts in that they were probably often used for cutting wood and felling trees. Some of these artifacts show signs of being hammered on the butt end, perhaps for the purpose of splitting logs.(Left to Right: 11613/1487, 11614/1487, 11861/1571, 56432/22174, 11615/1487, 48414/15407, 2135, 11619/1487, 2234) "

Web page produced by University of Wisconsin-Milwaukee Anthropology and Museum Studies graduate student, Kevin M. Cullen in 2006
https://www.mpm.edu/research-collections/anthropology/online-collections-research/old-copper-culture/artifacts


Copper Culture

“ There is disagreement among the archeological community as to the time period to ascribe to the Old Copper Complex. Dates range from over 7000 years BP to 3000 years BP. The greatest disagreement seems to be over the beginning age of the Old Copper Complex. Carbon-14 testing of organic materials found with Old Copper Complex artifacts has established a date of at least 6000+ years BP. Carbon testing of wood remains found in sockets of artifacts in our own collection has produced dates as old as 5900+ years BP. Copper continued to be used into proto-historic times, long after the demise of the Old Copper Complex. Many of the copper artifacts from the Old Copper Complex differ from those of later manufacture, with many of the later artifacts being smaller, less utilitarian and more ornamental. “

“ The presence of gas bubbles on the surface of a few Copper Complex artifacts has been taken by some as evidence that these artifacts were in fact cast from molten copper. I have yet to see empirical evidence to support this copper casting hypothesis, no molds, no furnaces, no copper drippings and no slag as found with ancient or historic foundry operations and no partially completed artifacts with a casting sprue still in place. What has been shown to be true through modern day experimentation is that gas bubbles are rountinely formed in the pound/anneal process. Gas bubbles have been shown to form when copper is heated to a red-hot state in the annealing process due to gas expanding and attempting to be released. The vaporization of impurities in the copper can account for these bubbles. There would actually be more surface gas bubbles observed if it were not for the highly oxidized condition of many copper artifacts which has obliterated them. This phenomenon has been observed numerous times in the process of copper tools being fashioned by modern day artisans using the pound/anneal process. “

David H. Peterson
Two Harbors, Minnesota
(Independent Researcher)
https://copperculture.homestead.com/ManufacturingCopperImplements.html


Pulling together a number of descriptions this is what I could determine :

- ‘Native Copper’ in this part of North America, appears to have its primary geographical source as modern day northern Michigan, Wisconsin, Ontario around Sault Set Marie.
- Natural copper is also found as random sedimentary deposited ‘nuggets’ over a wider range, most likely due to ancient glaciation effects.
- During the earlier phase of the NA Archaic period, larger ‘plates’ of natural copper were available, likely as surface finds. (3) As time progressed, deposits were worked through at least limited surface mining, plus using fire to crack open larger rocks to break free hard to recover plates.
- The larger size of these plates allowed for cold hammering into correspondingly large objects, allowing for the creation of tools like wedge axes and socketed adze forms. (4)
- As time progressed, creation of these kind of large working (?) tools fades, objects of copper become much smaller and more decorative types. Taken together (method and object size changes) this certainly suggests dwindling raw materials as the reason.
- There is no archeological evidence, either on objects or as related tools and importantly lack of furnaces / slag that would indicate smelting or casting methods were ever used.
- There is structural evidence seen on objects of the annealing process being used. (5)
- There is no specific structural evidence seen on objects for use of forging (hot working).


My first step, once I had gathered the basic data was to determine just which of the limited artifact samples I was going to use as prototypes. Looking over what was available, I decided to chose two objects from the Milwaukee Museum collection : 11616/1487 and 56432/22174
In both cases I only had ‘top down’ images, so details like thickness or possible curvatures could only be guessed at.
I have in the past found that the best method to get a clear idea the actual sizes and proportions of artifact objects is to attempt to modify the source images to ‘life size’. This was to prove a bit of a WAG in this case, as even though the images had scales, there were no units indicated. There was also a bit of image processing via Photoshop to reduce to black and white and increase contrast.

11616/1487 prototype to the left
56432/22174 prototype centre
My next problem was - just what materials did I actually have on hand? This would actually serve to modify the final sizes of the replicas, as much as scaling the images might.
As it turned out, I had one flat plate of copper, already partially forged, as well as a thick square block I considered about the correct size.

As discussed above, the original objects owe much of their shapes to their own starting materials, relatively thin plates. The artifacts would have been cold worked using hand held or possibly wood shafted stone hammers.
I most certainly ‘cheated’ in my own work! With access to a propane forge for easily controlled heating, I worked all my shaping working hot (6). Some of the initial profiling (especially taking the thick block to the blank for the adze) was done using my 75 lb air hammer. Also using a modern (c 1900) large, steel anvil, and modern steel hammers. I deliberately did my rough shaping using the slightly rounded surface of a crown hammer, finishing with my trusted round shaped main forging hammer. Both of these specifically chosen as I felt it unlikely square shaped hammers would have been used by the original copper workers here.

As the requirement was for an adze, a more specific design than the general ’spud’ shape seen in the artifacts, I curved the body of this tool more in keeping with later period iron woodworking tools I have made in the past. Each cutting edge was roughly drawn down to about 1/8 of an inch thick. I then (cheating again) used a belt sander to trim the mostly ragged edge to straight. The final edge (to about 1/16 inch) was then formed by cold hammering, which would also serve to at least slightly work harden this.
As a last step, the finished tools were cleaned to remove the dark oxide fire scale by socking in a salt + vinegar solution and scrubbing by hand.



All in all, I am extremely pleased with the final results.
The sizes are certainly within the range seen in the artifact samples, with the axe blade at about 3/8 inch thick. There might be some question on the curveture  used for the adze, with certainly is more based on past experience than knowledge of the artifacts.

Notes :

1)  “ The oldest (Old World) copper ornament dates back to around 8700 BC and it was found in the modern territories of Northern Iraq.
There is evidence for copper smelting and recovery through processing of malachite and azurite in different parts of the world dating back to 5000 BC. “
http://www.asarel.com/en/About/History/Copper_history.aspx

2) I had to dig around to get some numbers on the current value of scrap copper.
As industrial scrap, the current cost appears to be about $7.50 CDN per kilogram. Copper hit its peak cost about 8 years back, to about $12 per kg.
As a side note : Canadian pennies, before 1996, are 98% copper. It took about 420 pennies to make one kilogram weight.

3) The indication is that the natural copper being used here was formed as molten copper, formed and heated far underground, was forced into wide cracks in the surrounding rock matrix. Through the ages, natural processes (with a huge help via glaciers) forced up and eventually exposed or broke free these plate shapes.

4) The final weight of the two replicas seen here was 1700 gems, so about 850 gems each. These pieces are slightly smaller than the prototypes chosen, which themselves were on the larger end of the collected artifacts seen in reference images.

5) Copper, naturally quite soft, will ‘work harden’ as hammered. Eventually the metal will become hard and brittle enough that it can crack or break. For copper based materials, a worker can mitigate this effect by softening via annealing. In this case, the technique is heating the metal to a ‘blood red’ and quenching. The ideal practice is to finish a cutting edge by lightly hammering to thus work harden the final shape. Fine examination of the structural texture of objects shows this combination of methods having been used (thus understood by at least some artisans).

6) For any working smiths reading :
Copper is wonderful material to forge! Works in the orange ranges. As the melting point is in the 1100 C range, a propane forge is ideal. As the material cools, it merely becomes slightly (!) more rigid. (This unlike bronze, which depending on alloy, can become tragically brittle below forging temperature.)
Yes, as a material, is is roughly 10 x the cost of steel per lb. But on the other hand, experience has shown that an agressively forged copper object, despite the relative ease of the working, usually will command 10 x the finished selling price as well!
Re-cycled copper bus bar material is ideal.


Friday, November 01, 2019

Samhain Iron Smelt - Nov 2

Saturday November 2

the Wareham Forge

9 am work starts

5 - 6 pm for extraction


The general intent here is to have some numbers on different slag addition approaches within the use of the same furnace.
I propose using roughly the same ore mix and amount (so roughly 26 kg) as the two earlier smelts of 2019
This time clear out all the remaining inside slag, but not add any additional.

June - first use of the stone block
2.8 kg of iron slag added as the first three charges
actual ore addition = 24.2 kg (corrected for water)
bloom was 7.0 kg = 34% yield

October - second use of furnace
about 1/3 (??) of the slag bowl from June was left in place
no additional slag added
ore addition was 26.2 kg (not corrected for water, which is typically 10 %, so to match above = 24 kg)
bloom was 6.2 kg = 24% yield

This stone block furnace is based on the remains at Skogar, Iceland, and represents one possible interpretation based on some of the furnaces built there during, and after, the Viking Age. *

I suspect this will mean a reduced yield (ore into slag bowl)
The smelt is likely going to be a bit 'dry' as well, which may impact on bloom size / shape / density.
Past experience has pretty much shown adding slag at the start improves yield and quality.


* Note : I had been the process of preparing a very detailed report of my own interpretation based on three recently excavated 'Settlement Era' iron processing sites in Iceland. This work was halted with my sudden 'withdrawl' from the 'Firing Ancient Secrets' project - caused primarily due to differences over (lack of) information sharing and overall approach. 
At some point I will return to the considerable work I had undertaken, and publish my own observations as backed by the available published evidence. During my own involvement with 'Firing - Secrets' I had been expressly forbidden by the project leader from sharing ANY of the related information (!)

Paley Studio Auction

To:  OABA members.

I am send this notice out to the membership of OABA to let you know of an auction of the studio of a major American metalsmith, Albert Paley. 

Albert is from Rochester, NY where he has worked for the past 50 years is known for massive steel sculptures the most famous of which may be he gates for the Smithsonian Museum in Washington and the zoo in St Louis zoo. He was the featured speaker at CanIron XIII in Cape Breton in 2015.  He is closing his 40,000 sq.ft. studio this fall and will be selling off his tools and machinery in November.

... More information on the artist and the auction can be found at Albert Paley website as well as the website of the auctioneer, http://www.steevesco.com/wp/auctions-2/  ...

The driving time to the studio is about 90 minutes from Niagara Falls.   
Franklin Kains
Albert Paley is certainly one of the major figures in the contemporary artisan blacksmith movement. Born in 1944, this puts Paley in his mid 70's ( a decade older than I am).
Paley's big breakthrough was in 1973, when he was awarded a commission from the Smithsonian to design the portal gates for the Renwick Gallery in Washington, D.C. [10]  

Tuesday, October 08, 2019

Fall Iron Smelt ?

Experimental Iron Smelt

the Wareham Forge

Sunday Oct 13, 2109


‘Icelandic’ Stone Block - Re-used Slag Bowl


The furnace construction is one variation suggested by the excavations at Skogar, Iceland, in combination with the very real problem of available materials in Iceland. (1)
The on hand stone block furnace was constructed and test fired in June 2019. (2)



Excavations at Hals show clear C shaped remnants of the slag bowls created during an iron making sequence. (3)

Most of the experimental tests undertaken at Wareham involve attempting to explore limited variables, focused to understanding historic process. To that end, it is common to only use any single furnace build at most only 2 or 3 times - often only a single use. The standard has been to completely clear away any remaining interior debris of slag before a second experiment.
It was noticed that the fragmented slag bowl from the June smelt closely resembled what was seen on the excavation drawings from Hals (and other sites).

The bottom of the exposed slag bowl, with the bloom still in place




The set up for the upcoming experiment will be to use the existing stone block furnace, retaining the slag bowl still in place (about 2/3 of the initial).
    •    ‘standard’ furnace layout (4)
    •    copper tuyere
    •    electric blower (high volume air)
    •    ‘DD2’ ore analog / 30 kg (5)

The specific question?
How will the retention of an earlier created slag bowl effect a second firing in the same furnace?

Interested in Attending ?

Day start : 9 AM
Main Sequence start (typically) : about 10:30 AM
Extraction (estimated) : 5 PM

This event is considered ‘Open Invitational’ :
  • Those wishing to attend are welcome, but I ask you e-mail me so I can manage things like parking and support equipments.
  • This is not specifically a teaching situation. There will be plenty of chances for those keen to both learn and especially participate. (Dirty jobs to be done!)
  • Those hoping to directly participate should wear work clothes of all natural fibre, and ideally wear boots that fit up over the ankle. Safety eyewear and gloves will be provided.
  • People are advised to bring lunches with them, the working team can expect to grab while they work.

Directions :

The Wareham Forge is ‘pinned’ on Google Maps
The location is roughly 1 1/2 hours north of Brampton, just off highway 10, beyond Dundalk.
(About 2 hours NE of Waterloo for any ML302 students)
http://www.warehamforge.ca/directions/index.html


1) Clay is generally not found in Iceland. What few specific locations have only yielded a vary low melting point material, itself not suitable to withstand the normal operating temperatures within a bloomery furnace.
Excavations at Hals, Iceland exposed massive furnaces constructed of diagonally piled cut grass sod strips. These may (or may not ?) have had a thin liner of such clay, but the main support remains the sods.  (see the earlier Hals series)
One of the furnaces at Skogar clearly indicates the remaining lower part of the furnace to be constructed of smaller stone blocks. As is most often the case, the entire upper portion of the furnace is missing.

3) ‘Towards an Icelandic Smelt’ An evaluation of the Hals site (Fall, 2008)
http://www.warehamforge.ca/ironsmelting/HALS/index.html

Monday, September 16, 2019

Ontario Gas Tax Stickers

Open Letter - copies sent to :
Premier Doug Ford 
(direct e-mail = doug.ford@pc.ola.org )
Ontario Ministry of Finance
(via web site / only allows 500 characters! = https://www.fin.gov.on.ca/en/contact/index.html)
MPP Bill Walker, Bruce/Grey/Owen Sound
(via web site / only allows 1000 characters = https://billwalkermpp.com/contact_email.php)
Conservative Party of Ontario
(via web site = https://www.ontariopc.ca/get_in_touch)
Conservative Party of Canada
(via web site = https://www.conservative.ca/contact/ )
Commissioner of Canada Elections
(direct e-mail = info@cef-cce.ca )
(1)

I am contacting you as a resident (and tax payer) of Ontario.

This is relation to the Ontario Conservative Government (Doug Ford) and its current media campaign about the Federal carbon tax - applied to gasoline.

taken from the CBC web site (below)
I had bought gas at the same location in Authur Ontario, first on Sept 5, then again September 12. There was no sticker the first time, it was in place the second time.
When I paid for my fuel, I asked the attendant if the station was required by the (Conservative) Government to post the stickers. He told me that this was in fact the case, and they were forced against threat of fines.

When I returned home, I attempted to get more information about this, via the internet:
https://www.cbc.ca/news/canada/toronto/carbon-tax-stickers-law-ontario-1.5265380
https://www.nationalnewswatch.com/…/ontario-gas-stations-m…/

The indicated articles state "The (Ontario) government has earmarked $30 million for its fight against the carbon tax..."

Guess who is paying for THAT - and out of MY pocket?

Please not that I am not addressing here my feelings on Climate Change (2), and my personal responsibility towards some attempt at dealing with this. I am considering nothing more than the purely POLITICAL question represented.
I found the ‘information’ content of the sticker misleading, and personally consider it nothing less than partisan propaganda.

I specifically note the official start of campaign for the Federal election was September 11. 
Yes, I see that the policy was put into force starting August 30. However, to add insult to injury, it is hard not to see this current use of forced ‘announcement’ little more that an attempt to both boost support for Conservatives, and at the very least,  bend  Canadian laws on election advertisement.

I consider this nothing less than blatant political propaganda by Ford.
Paid for by the Ontario Taxpayer.

Darrell Markewitz
Wareham, Grey County
info@warehamforge.ca


Notes :

1) I have found the methods permitted for the transfer of information to my Government ministries, and my elected 'representatives' to be at best restrictive.
a) the use of web site 'form filling' for the majority of the offices listed. In most cases, I was also required to submit considerable personal contact information (addresses and phone numbers). I will fully be expecting these will be used (in the case of all the Political institutions) to send me unwanted advertisements.
b) In two cases (as listed) there were character limits imposed. These did not allow for any correct or complete sending of information on my part. 
The fact that one of these was for my local MPP, Bill Walker, I find particularly troubling. 

2) I have written a number of times here about 'Carbon and the Forge'
I state once again that am absolutely certain of the reality of Climate Change from both the scientific data, observations by others I trust - and my own personal experience. 
I also repeat my belief that I share a personal responsibility for not only contributing (and continuing to contribute) to Carbon emissions, and further, a responsibility to undertake actions to reduce my own impact on the environment. 

Thursday, August 29, 2019

Adaptable Furnace Base

This piece of equipment a long time coming!

The concept started with my experience at the Scottish Sculpture Workshop in 2017. Unlike previous work there (on the Turf to Tools project) the 2017 visit was intended purely as a personal artist's retreat. A good chunk of the one week was spent with Beth Bidwell in the ceramics studio. I returned to a lost love (wheel thrown pottery) and took part in several kiln firings. This included raku, using a propane fired furnace.


This was a fixed propane fired furnace base, with a moveable top section.
SSW uses a number of high BTU output propane burners, which they can switch out to provide heat for a number of different furnace / heating applications. (Wax burn out, bronze and iron casting, ceramics, special projects.)
Here you see the furnaace base, which is made up from a cut truck wheel rim, lined with castable refractory material. A simple hole in the side directs the blast from the propane burner. This runs on a ventri effect (no electric blower required). Although this base is quite heavy, it is mounted to a wheeled cart to allow it to be shifted around the concrete paved SSW central courtyard.
SSW alumni George Beasley had created the upper kiln segment seen here.
A frame and counterweighted pulley system is attached to a section cut from a metal 45 gallon drum. This containment was lined with k-wool insulation, and had a couple of viewing ports and top exhaust vents cut into it.  The counterweight system allowed the upper to be shifted upwards and easily blocked into place as this was done.
In use, the upper area was set with kiln shelves and supports, containing the previously bisque fired ceramic pieces to be placed. A bit of care needs to be taken at the initial ignition of the propane burner - too much heat, too quickly, will simply shatter the pottery. Over time, the propane feed is increased, eventually bringing the entire upper stack to correct high temperature. The required point is judged by using 'cones' - the heat effect on these observed through a viewing port. *

I was impressed on how basically simple this whole design was.

For a good long while now, I had wanted to set up a larger equipment for bronze casting at the Wareham Forge. I have done a fair amount of small scale metal casting, with lost wax investment (silver and gold), using tin alloy (pewter) in stone, and using the 'green sand' method for bronze. I have been limited in the size of bronze objects by the heat source - with a oxy propane torch. This allows me to effectively head only a small crucible, roughly the volume of a walnut.

Original lead artifact (c 800?) / interpretation in pewter / duplicate in bronze
My intent was to build a furnace that would be able to heat about a litre volume of bronze. At least to start I would continue with the green sand mould making, but this would allow me to cast small sculptures, sword or knife hilts, things like door hardware or boat fittings.

I had originally figured just to build the burner assemblies from pipe fittings, much as I had constructed a number of propane gas forges in use at the workshop here.

Over the winter, Princess Auto had these simple propane burners on sale. (For half price @ $25 each - the included, CSA certified, 10 foot hose normally runs about that much!) I bought three. These burners are rated at 500,000 BTU each.
In January, our 30 year old electric water heater (finally) failed. Although replacing it proved a real pain, it did leave me with the steel tank.
Add some scrounged fire brick I've long had on hand.
For ease of use, apply a heavy utility wagon wheel assembly (also from Princess Auto, purchased a good while back for just this kind of use).

Finished furnace base unit

I had cut (using a zip disk) the bottom roughly 1/3 away from the full tank.
That left me with a short cylinder, having a slightly domed base, all made of 1/8 inch thick steel. The interior is glass coated (think the enamel finish on an older stove), but that will not figure into the construction.
Outside Diameter = 24 inches
Height = 18 inches

Next step was measuring equal thirds around the circle, then cutting three suitable sized holes through the steel for eventual mounting of the three burners. I used the oxy-propane torch for this. ( I freely admit that cutting is something I never have done enough of to really get that good at!). I ended up using a worn down disk on my angle grinder to even out and correctly size each hole.

view down the completed interior
I have a set of half circular pottery kiln shelves, each of high temperature refractory plate, about 5/8 inch thick. One of these I cut to fit as fully as possible over the inside base of the steel shell. In the image above, you can see the edge of the part starting part circle, with the two smaller pieces I shaped to fit into the remaining base. This gives me a durable, hard, flat, fire proof floor. To fill the gaps around the slightly domed steel base, I used a refractory type material I mixed up. I had been saving damaged low density fire bricks, which I broke down to about the consistency of course sand. I mixed this 50 / 50 with powdered potter's clay, with water into a paste. (This using 'Hawthorn Fire Clay' - a fairly high melt point type I use here for building clay cobb iron smelting furnaces.)
As it turned out, the spacing proved almost perfect for the medium density fire bricks I had on hand. Each burner would be centred on one brick, with two bricks spacing around between each burner point. Once the fill and floor plate was installed, the remaining wall height came to the 9 inch length of the bricks (Ok - I did measure this out initially and cut to provide for this.) The resulting interior diameter is 12 inches.
I dry fit all the bricks, to transfer the location for the holes from those cut in the shell. As it turned out (luckily) the holes required were exactly the same size as the largest diameter in my hole cutting saw set. Short work with the hole saw mounted in a drill (cut from both sides to get through the thickness). Given the relatively fragile nature of the fire bricks, this proved a much easier task than I had suspected.
Again test for fit. Each of the bricks was mounted, again using the clay/brick dust mix as filler in the triangular gaps. It is expected this mix will contract a bit (10 %?) as it dries, but given the tight fit of the bricks I don't expect this will present any special durability problem in use.

close up of the master valve and fittings
Figuring out just how to link all the burners together proved a bit of a pain. The tubing diameter for all the pieces on the burners as purchased proved to be 1/4 inch. Maybe a 'standard' size - but not a size that any of my local stores had in supply. Once again, McDonald's Home Hardware in Dundalk saved me. They had just enough fittings, once a set of 1/4 to 1/2 inch couplings were found. This allowed me to get just enough of the (slightly more available?) 1/2 inch steel pipe fittings **
With use of a short piece of 1/4 thread fitted hose I had on hand, I managed to link all three burners together, via one central shut off valve. I further protected the short gas hose by covering it with the plastic pipe seen above.
I kept two of the burners with the original knob equipped flow valves. The central burner (seen above) is 'always on' - controlled by the main shut off. In use, you ignite that first burner from the main valve, then can control each of the remaining two burners individually. This combination should give the greatest flexibility and control over the propane flame = temperature.

The ideal would have been to mount the burners at a slight angle, both off centre along the side of the circular containment and also pointed down slightly towards the floor. This combined angle would server to create a circular vortex inside the furnace chamber, actually improving the flow of heat within. As it turned out, the distance from the brick interior through to the outside of of the shell, with burner mounted, can be seen to be almost exactly the distance to the air input slots already designed into the burner. By maintaining this, there should be the ideal amount of input air to feed the burner as it was original designed.

The completed furnace base unit weighs about 60 lbs. The combination of weight and size, plus the need to be able to store it when not in use in a working shop, lead me to use one of the utility wagon bases I had also purchased at Princess Auto some good while back (again on sale). I welded up a support from angle, which bolts on to the wagon base. The large 8 inch diameter wheels, which pivot on the front, make for good handling over the dirt floor of my workshop. As mounted, the completed unit stands 24 inches tall - a good height for manipulating the eventual crucibles. 


The last step is to take another of the kiln shelves and pattern and cut a suitable lid for this configuration of the furnace base. Ideally there should be a central hole cut, to allow burned gasses to escape. This will also allow two other functions when melting bronze :
1) Allow direct observation into the interior of the crucible (judge melting point)
2) Allow addition of more bronze material during a melt.
Will also need to figure some simple handle mounting to allow this lid to be quickly removed to extract heated crucibles.

Right now I have just used one of the supply hose assemblies that came with each burner. This pulls pressure straight out of the propane tank. There are two possible problems with this :
1) I have 40 lb propane tanks here as my normal supply for the gas forges. I have no clear idea how much fuel this x 3 burner system will draw, or how fast. The larger burners at SSW seemed to function a long time, but that was pulling from a 100 lb cylinder - one per burner. Testing required!
2) As designed, the burner is pulling straight off tank pressure. This is sure to drop (significantly) over the course of a longer session of heating.
I may introduce one of the variable 0 - 30 step down regulators into the system. This itself may need some testing to determine how this effects the overall operation. (??)
Right now I want to give the clay mix a couple of days to completely dry before the initial firing. (Potential steam explosion - and to reduce cracking effects).

COSTS :

Steel Shell = recycled
Firebrick = recycled (but about $10 per brick = $90)
clay = 1/2 bag = $12
floor plate = on hand (but about $55 each = $110)
burners  = on sale (1/2 price) at $25 each = $75
fittings = various = total $55
wagon base = on sale (1/2 price at $60)
TOTAL AS COMPLETED = $400


To start, I will be making casting crucibles of that same clay / brick dust mixture. I have had good results in the past using the same kind of clay / sand / horse manure mix used for the smelting furnaces. I may end up investing in a couple of modern high temperature refractory crucibles as well.

Next overall part of the project will be converting the upper portion of the water tank pieces into a containment to allow this furnace base to be used as a ceramic kiln as well...


* Use of 'cones' is a 'traditional' method of determining pottery kiln interior temperatures, still widely used in the absence of (often expensive) electric / electronic instruments.
A set of small, thin, pyramid shapes are made of clays with differing melting points. These then are set in a line, lowest slumping cone to the view port, increasing in heat effect towards the interior. Watching each cone slump in turn gives the potter a fairly accurate read on the furnace temperature.

** As it turned out I bought ALL the 1/8 and 1/2 fittings Brent had on hand. Well, Tuesday is order day for the normal Thursday delivery of re-stock. Sorry to anyone in Dundalk who got caught short. (But honestly, commonly I'm 'the only one that buys that stuff'...)

Tuesday, August 27, 2019

‘I was a Punk - Before YOU were a Punk’ *


On Co-Opting Symbols

Note to Readers:
This is proving a very difficult piece to write.
I am fully expecting a lot of kick back - but I would ask you read the whole piece - first. Comments will be welcome, but expect limits to ‘free speech’ will be applied. 


Thor's Hammer pendant from a Viking grave from Bredsatra, Sweden. At the Museum of National Antiquities' collection in Sweden, 10th century  (from a Pintrest collection)

What do you do, when objects you long have owned, suddenly are grabbed by some specific group, and incorporated into their personal vision?
Suddenly lifted completely out of context.
Look to the left hand in the image below:
Demonstrators carry Confederate and Nazi flags during the "Unite the Right" rally at Emancipation Park in Charlottesville, Virginia, on August 12, 2017. (Emily Molli/Sipa USA | AP Photo)
Or you realise that there may be new meanings applied to an old symbol, which you may have first chosen in innocence.
But then was co-oped by others, and distorted into something entirely different. This new association most certainly something you can not agree with!


Now, there are two quite different things going on here.
If you display an SS badge, or a Swastika flag, it is pretty damn certain what you are intending.
Seriously, you can rant all you want about ‘freedom of speech’, but everyone knows the pit of hate behind those symbols in the Modern Age. And exactly what you are clearly stating and promoting.

Modern Era and current Neo-Nazis, starting in Europe, had / have adopted many icons from ancient Goths and Norse. This all in a attempt to create a (false) ‘lineage’ to their views. The fascination of Hitler and his gang with the occult most certainly is another reason. There is most certainly a direct connection being made by current Neo-Nazis, both in Europe and as today active in the USA, with ‘Heathen’ / ‘Odin-ist’ practises and symbols. **

But to be absolutely clear, the historic artifacts had absolutely no connection what so ever with these purely modern, propaganda, uses of the imagery.
There was absolutely no concept of ‘White Power’ during the Viking Age.
Period.
(Show me some Archaeology. Not some written fantasy from the 1930's!)

Context can become everything.
I have a bronze ‘interpretation’ of the Bredsatra hammer. I was given it as a gift, back in the mid 1980's. Purchased by a friend who got it at the Coppergate Viking Centre in York, England.
When worn with obviously all Viking Age clothing, inside a living history demonstration, this is fully intended to represent an individual who was following the primary religion of that time, place and Cultural set. This is a historically based character, created for purely educational purposes.

If I should chose to wear that same token with street clothes, it may - or may not, symbolize my own personal faith view.
It may be most safe to say that if the token is worn under my shirt, next to my skin, it is most likely to actually be a religious symbol. Consider a Cross, Star of David, Pentacle, …
'Thor's Hammer' necklace, 1993. Pendant based on Rømersdal, Denmark
Worn over clothing, highly visible?
Seriously - it may just be ‘a nice bit of jewelry’.
But this may also be fully intended as a visual signature of membership in a ‘club’.
Wearing a Celtic ringed Cross? Likely you are showing both Christian and Irish associations.
Wearing a Thor’s Hammer? May certainly mean you are following some version of North European Paganism.

The same symbol printed on a T shirt?
Again, the most typical is ‘that is a cool design’.
It may only represent ‘I’m interested in that Cultural set’.

But horribly - increasingly, with the (repeated) rise of the extreme Right, White Supremacist and Neo-Nazis?
The ‘Thor’s Hammer’ is becoming yet another ‘code’ symbol for those groups.
Maybe like shaving your head?
Or sporting an SS Lightning or Swastika tattoo.

This becomes a form of Cultural Appropriation.
A very, very destructive kind.


While I was researching this piece - another symbol association struck me:

Neo Nazi demonstration in Myslenice Poland.
Contributor: Bart Pro / Alamy Stock Photo

Now, I have been working with Celtic inspired designs for some 45 years. This working primarily from artifact source materials. The objects made in Ireland, in the period of the Norse expansion (c 800 - 1000) show an wonderful blend of Celtic and Norse, pagan and Christian. I love the sweeping reversal curves from earlier La Tene objects. I have never been especially interested in Irish Catholicism, or it’s symbol meanings, however. The only time I have specifically used the Irish style 'high circle cross' in my work was in the creation of a forged steel grave marker.***

Taken from Avia Venefica : Celtic Cross Meaning
It should be remembered that the ancient carved stone cross seen above is not the typical. I have seen a number of these artifacts personally (Ireland and Scotland, museums in North America). The most common layout for the Celtic / Irish cross is a with a very long lower shaft, then three much shorter upper arms.

If you did an open internet image search using ‘celtic circle cross’ - this is what you would see :

Check on the reference link for image # 2.
The association of this symbol (also called ‘Odin’s Cross’ ??) with Neo Nazi’s is listed.

Reference link on image #7 ?
“ Legal disclaimer
This image shows (or resembles) a symbol that was used by the National Socialist (NSDAP/Nazi) government of Germany or an organization closely associated to it, or another party which has been banned by the Federal Constitutional Court of Germany. The use of insignia of organizations that have been banned in Germany (like the Nazi swastika or the arrow cross) are also illegal in Austria, Hungary, Poland, Czech Republic, France, Brazil, Israel, Ukraine, Russia and other countries, depending on context. In Germany, the applicable law is paragraph 86a of the criminal code (StGB), in Poland – Art. 256 of the criminal code (Dz.U. 1997 nr 88 poz. 553).”


How careful must we be, that the brush, now covered in black and blood, may now end up painting us as well?




 

Note : In preparing this piece, I have lifted a number of images off the open internet.

* Title taken from : the Tubes, 1977, song of the same name


** Before readers get offended!
I am NOT implying that any specific religious practice always implies a specific political viewpoint. If anything, the merging of Nazism with Odinist should be even more offensive to any who reject those political concepts.

*** Long installed in a small cemetery near Belleville, Ontario. Unfortunately, I have never seen the work as installed - or even have a reference photo of the finished piece. It stood about 5 feet tall. 

Sunday, August 25, 2019

Antique? Vintage? Modern? (a Helmet)



On 2019-08-24 10:04 PM, 'M.D.' wrote:
I have a question about a helmet I was given some years ago, which I'm now hoping to sell.
The person who gave it to me first thought it was a costume replica, and now believes it to be a WW1 tank helmet. It was found in an antique shop.

It looks a lot like a medieval helmet and is very heavy. The back has a flexible "lobster tail" neck protector and the visor lifts somewhat.
An online search reveals nothing similar. Many helmets are more elegant; might this be a helmet a grunt soldier might have worn?
There are no tank helmets online that look anything like it.

Ok - so here is what I remembered, what I found, and what I think.

On tankers helmets:
I had a small drawing in a reference book
described as 're-inforced leather helmet'

image from : Weapons and Warfare of the 20th Century - Morris, Johnson, Chant & Willmott
With a slightly better idea what I was looking for, I was able to plug into Google images search on the internet and come up with a description at the Imperial War Museum in England (link):
image copied from the Imperial War Museum
So at least for British tank crews, your object remains quite different, as you had indicated. There was still some extremely limited use of plate armours in WW1 (notably massively heavy 'sniper proof' combination chest and head shields). This proved a wasted effort, as by that point the weight of the bullets easily penetrated anything able to be carried. (I saw several samples of these pieces at Ypres in the museum there in 2016 - with bullet holes.)


Ok - so what DO you have here?
I've sent back two of your images, marked up.


(green) : The original surfaces have been spray painted black (obviously a modern addition!)
 - There are a few areas that show the original metal surfaces.
 - The rust effect on those surfaces looks to be that you see on mild steel, not wrought iron.
 - These surfaces also don't have any forge scale, all the forming has been via cold bending or hammering.

(purple) : You mention how the visor only can be raised slightly. This would be a very bad design if this was a 'working' helmet. The visor is in fact shaped primarily. as a flat curve (section of a cylinder). It really should be dished (section of a sphere) in a shape that conforms to that of the skull.


(yellow) :  All the plates are formed of the same, very thin, (mild steel) metal stock.
- The metal would be extremely thin for actual wrought iron plates
- You can't really tell in the images, but this appears the same thickness for the body of the skull as well.
These do appear very thin, against the ideal for the purpose of actual combat. This is seen in the visor, which is one of the normally thickened target areas on an armour. the skull plates should also be considerably thicker for the same reasons (you can judge if this is the case?). In combat, most strikes will come to the wearer's left side skull, which commonly is thickened to protect against these impacts.

(red) - These seams look to be arc welds.
- The beading further looks to be stick welding.
- There has been an attempt to grind the welding beads smooth and flush
-
The uppermost line of welds appears to have actually burned through the metal - which indicates both not the best work - but most importantly again that the skull plates may be quite thin metal. 
A look to the inside surfaces of those seams will tell you a lot. I expect you will find the lumps of the weld bead.


So - what time frame does this all give us?
- Mild Steel = post 1855.
Wrought Iron was still being produced, in smaller and smaller amounts, up into at least the 1920's - 30's
- Arc 'Stick' Welding = post 1870.
Stick welders are still widely available. Largely supplanted in current workshops by inert gas welding (MIG), which itself is only after about 1945 (which would be definate modern dating).

One of the big indicators for me is the construction of the skull. It has been made of several narrow pieces, each partially dished, as cold hammering, then the segments electric welded to create the sphere of the skull. This is a very modern, 'amateur' approach to creating the required shape.
The historic method is to hot dish the skull from one single piece. That starting plate would have been forged to a modified thickness profile to start with, thinner at the edges, and thicker in the centre. Taking a flat circle and forming it into a half sphere involves dishing in the centre and raising along the edges. Dishing thins the plate, raising thickens it. Ideally the variations in starting profile would allow for a *uniform* thickness overall in the finished skull - after the stretching and compacting of the two forming processes.


'Antique' as a term gets pretty slippery. 'Vintage' may be fair. This could possibly be a late Victorian era 'replica'.

But, sad to say, I think what you really have here is a helmet made by a mid skill grade, modern, re-enactor. Likely some point in over the 1980's or 1990's.

Note : Images of the object under consideration, from the original questioner. Name is withheld for privacy.

Tuesday, August 20, 2019

Cow Magnets & Phase Changes

This piece sparked by some stories being swapped recently on the Association for Living History Farms and Museums discussion group…

Cow magnets, easily available at my rural farm supply stores around Grey County in Ontario (Canada), have long been part of my blacksmithing tool box.

For those outside the 'Art and Mystery' :
The ideal temperature for quenching (most) cutting edges after forging to shape is what is called the 'critical temperature'. Without going into the science, iron materials change from a rigid solid, into what is technically a 'plastic' at a certain point in their heating. At this point they also stop being magnetic.
Although a skilled smith can judge this by colour and trained eye - the certain way is just to touch a magnet to the hot metal. Just at the point the metal cools enough so a magnet just barely starts to stick? That is your critical temperature.
This certainly a good 'trick' when working in the sun with outdoor demonstrations!

Those long bar magnets many of us used back in public school would be even better (if you could find one).
I recommend my students just get a cow magnet, these run about $5 CDN around here. I've been using the same one for over 30 years for just this purpose.
ok - I see the technical blade makers reading this starting to pout just a wee bit.
It is not that simple :

Noon’s Knives
 https://noonsknives.blogspot.com/2017/03/

Note right off the start - the carbon content (even in small % variations) shifts things considerably here!
This is hardly any surprise to the experienced blade smiths reading. Right of the start - there is clearly no ‘one size fits all’ in terms of ‘perfect’ iron / carbon mixture - for ALL cutting edges.  (a)
As it cools to 770 °C (1,418 °F), the Curie point (TC), the iron is a fairly soft metal and becomes ferromagnetic. As iron passes below the Curie temperature, no structural change occurs, but the magnetic properties as the magnetic domains become aligned. (1)
But leave the details here, and accept the generality of the original quote at the start. (Do remember it was intended to a non metalworking audience - and really was about Cow Magnets, not technical blade making!)


Another Cool Thing:

This was demonstrated to a group of us at Lee Sauder’s ‘Smeltfest’ event in 2008 - by Jesus Herandez.
If you take hot bar into a really dark room, then watch it as it cools.
"At the critical / transition point, the bar will flash to a brighter colour = higher temperature, for an instant." Oh, yea, we all said...
Wow!
As I understood the demonstration:

From 'Iron, Steel and Swords' by Helmut Föll

As the atoms shift from ‘face centred’ crystals / Austenite back to ‘body centred’ crystals / Ferrite, there is a release of energy as they shift over.  (b)

Further Reading?
‘Iron, Steel and Swords’ - Helmut Föll
https://www.tf.uni-kiel.de/matwis/amat/iss/index.html





a) There are a number of past discussions related to this topic on this blog. What the tool is intended for most certainly effects the choice of material. Some combinations of hardness against flexibility, plus other desired qualities (rust resistance) may be possible with modern, exotic (?) alloy types. Often working directly *against* ability to easily forge.

1) ‘Allotropes of Iron’ - Wikipedia
https://en.wikipedia.org/wiki/Allotropes_of_iron

b) Ok, my eyes start to glaze over too.
The best (and by far clearest!) explanation of all this is again ‘Iron, Steel and Swords’ :
Reading Phase Diagrams - part 6.1.2 / 6.1.3

Saturday, August 03, 2019

Viking Age iron smelting air systems?

Those following me may be aware that I am participating in the Hurstwic 'Firing Up Ancient Secrets' project, set for August 23 - Sept 5 at Eiríksstaðir in Iceland.
My contribution is both my research into Viking Age iron smelting methods, and my (considerable) experience with an experimental archaeology approach towards understanding those systems. 
I have been doing a lot of background research and pondering about everything related to bloomery iron making during the Viking Age of late * 
The following is modified from a recent communication with a fellow experimental researcher:



Air systems are especially an area of investigation for me.
What I see as the problem is this:
- We can make blooms that almost exactly resemble the ones found in the archaeology. (Understanding there are not that many samples that have been found.) But to do this requires the application of large volumes of air, and high burn rates. (This based on the pioneering work of Lee Sauder from Virginia  )
- There is almost no hard evidence on what bellows might have looked like from the Viking Age itself. Two images from the period, no object remains what so ever. (Be very happy to be proven wrong - if anyone reading knows something!) This specifically true for possible iron smelting bellows - for which there are virtually no indications on type or size at all. Possibly some signs of post holes that might be supporting frames?

I note here that you most certainly can get some iron produced with low volumes of air. This has definately been proven many times by those working at European open air museums, using what are 'Early Iron Age' methods.
But I consider the quality of the blooms created a very important indicator in results.

My own reconstructions of the blacksmithing bellows, based on those two illustrations, creates a twin chamber unit which in working tests produces roughly 120 - 160 litres per minute (based on one stroke per second)
If you compare this to the 'ideal' air flow requirements, this is at best 25% of the required volume - if you are expecting to create a dense bloom that resembles the ancient ones. (For the 25 - 30 cm interior diameter most of us are working with, air in the range of 500 - 800 LpM.)

So:
Most of us in the experimental community use all sorts of different measurements - or no measurements at all.
One standard is 'charcoal consumed over time'. Again, there is no consistent way this is reported, I see a lot of European workers using 'kilos per hour'. Here in North America (again thanks to Lee) the standard is 'charge amount per minute'. The ideal is usually quoted at '5 lbs over 6 - 8 minutes' (so make that roughly 2 kg).
Here we more typically are running at closer to an overall 1.8 kg every 10 - 12 minutes (so about 9 - 11 kg / hour) Our blooms are intentionally on the smaller size (normally 30 kg ore to about 5 kg iron).

The questions are :
What is the air volume produced by the various *theoretical* Norse type iron smelting bellows?

Ideally, to get any kind of understanding of this, individual teams need to undertake some sort of measurements.
- What are the physical dimensions of the bellows unit being used?
- What is the stroke count per minute?
- Is the actual production volume (when hooked into a working furnace) measured?

- What are the physical measurements of the furnace (especially the interior diameter at tuyere)?
- What is the average burn rate over the smelt?

- What is the yield?
- What is the quality of the iron produced?
(This last is so dependent on the quality of the ore being used - it may not prove a really valuable comparison!)




Right now I am working with a group attempting to experiment with a possible Icelandic based system. At present they are intending to build a large, single chamber bellows (more or less like one half of the known Norse type). This has been tested all of once - and I think is not the way to proceed into the Iceland side of the project.

There may be some element of just how the air flows into the furnace?
- A Norse twin chamber (larger smelting size) produces a flow that never stops, but with changes in volume as each chamber is pushed. The delivery pressure can also be modified each stroke by the force of the push. (Consistency a problem). Requires 3 - 4 workers.
Possible Norse Smelting Bellows - Vinland 3
- Multiple Norse twin chamber, small blacksmith size, linked to a central air bladder. The flow never stops, pressure modified by a weight on the bladder. We have tested this system out twice, but the main draw back is the larger number of workers required (6 - 8).
Blacksmith's bellows linked by bladder - SCA 50
- The single chamber being considered by Hurstwic has no historical examples (that I am aware of). It will produce air that starts and stops on each stroke. Pressure can be modified by the force of the push. (Consistency a problem) Requires 3 - 4 workers.

- A 'great bellows' (two stacked chambers, 'double action') is Medieval at best. This will provide a fairly constant blast, pressure consistent (modified by weight on the top delivery side chamber).  I see a lot of people using this post 1300 system  - and calling it Viking Age. Requires 3 - 4 workers
Settlement Era Great Bellows - Williamsburg
- Obviously use of a modern electric blower gives a constant blast (volume and pressure). Solves the labour problem!


Another extremely important element - which will effect the entire design of the furnaces, is the tuyere system itself. (To be discussed in a further posting)


* If regular readers have noticed a sharp decline in postings here over the last two months - this is the primary reason. 
- June was DARC's major demonstration at Upper Canada Village, plus my presentation at the ALHFAM conference.
- July marked a major construction project (upper deck structure and roofing) at Wareham
- August? 
* formal paper based on the ALHAM presentation to be written
* detailed research into iron smelting in Norway and Iceland
* writing a report relating that research to the Firing Secrets project
* preparing a lecture presentation (before the Canadian Ambassador to Iceland!)
* equipment load out and packing for the trip
 

February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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