Monday, March 26, 2012

Smelting at Smeltfest

(this is a duplicate of a post on Bloom to Bar)

This clip shot by participant Jesus Herandez

This clip from our third smelt during Smeltfest 12 shows a number of reasons why my participation there is valuable (to me!).
The concentration at Smeltfest this year was in part on working with a new magnetite ore.
On our first smelt, we did not produce any iron. After some consideration, the thought was that we had purified the ore (double magnetic sorting) too much, not leaving enough glass producing elements to create the correct working slag bath inside the furnace.
On the second smelt, the result was a (quite surprising) 'white' cast iron. Not what we expected at all.
On the third smelt seen here, the result was a solid bloom of a middle carbon steel. Perfect!

You get some idea of how a well skilled *team* is the ideal situation, as well as having access to some large scale equipment.
During the extraction itself, Lee Sauder is managing the opening of the furnace and pulling the bloom. I normally work as 'safety man' - shovelling away hot fragments and burning charcoal, plus keeping the tools close at hand and in some kind of order.
As soon as Lee extracts, the bloom is weighed (on a large scale) and then quickly transferred to a thick steel plate set into the ground. At this point two hammer men (Steve Mankowski and Shelton Browder here) strike over the surface to both knock off the loose slag. and compact in any looser bloom fragments. (1)
At that point the bloom is loosing its initial heat. You see the action jump into the main forge area, where Lee has set up a special side draft coal forge. Once re-heated back to a welding temperature, again Steve and Shelton hammer the surface, increasing force as they compact the bloom further.
Next the bloom is transferred over to Lee's 300 pound mechanical hammer. Not only massive power, but also this hammer has an extremely large working surface. You see the bloom compressed into a puck, then that flat disk cut into quarters using a pair of specially designed cutters under the power hammer. (2)

Last, there is a sequence showing Skip Williams spark testing a still hot quarter section to determine carbon content. (3)

Just to prove there is still more art than science in bloom smelting, our fourth attempt *should* have produced another flow of high carbon cast iron. The result? Middle carbon steel again, although not with the same yield or consistency as smelt 3.
Hmm - some more consideration and experimentation seems in order here!

Meanwhile, back to Wareham :

1) The team I normally work with at Wareham does not regularly include any trained blacksmiths. I'm usually pretty much exhausted by the time I get a bloom pulled. So my normal ability to make the best use of the extreme heat of a freshly extracted bloom is quite limited.
On any secondary attempt to heat and work a bloom mass , I rarely have any assistance - so must hold and cut working alone.
2) The small air hammer in my shop is only 50 pounds head weight. More significantly, it has a very small working table, only 4 x 1 1/2 inches. This makes it extremely difficult to balance an irregular bloom and compress or work it.
This is why the start of the Bloom to Bar project has been taken up by preparing a new 30 ton hydraulic press.
3) My objective (like the historic one) has been to produce a *low* carbon iron. This softer material is much easier to forge into objects.

Saturday, March 24, 2012

International Iron

Shropshire International Iron Working Festival 2012

Event date:
Wednesday, 8 August, 2012 to Sunday, 12 August, 2012
Organised by:
Shropshire Council

Following the success of the international iron smelting weeks, held since about 2003 across Europe, This year the smelting week will take place in the UK.
Shropshire is renowned as the cradle of the Industrial Revolution with the occurrence of minerals and ores supporting the development of manufacturing processes from pre-historic times to the present day. In particular the working of metal ores has shaped the landscape as mining and quarrying, with attendant settlements and roadways, has left a physical legacy which is clear to interpret today.
(image and text above from the ExARC web site - see the full listing)

I would just *love* to be able to attend this!
Even funding not considered. the date places the event just days after I will be returning from DARC at LAM 2012 (L'Anse aux Meadows NHSC). Also directly on top of the Celtic College and Festival in Goderich.
Maybe next year? (No wait, that's CanIRON 9 in Quebec, and maybe a resarected Early Iron in the fall.)

PS - I'm in Corning to view the Glass Museum later today. This is the last element of the extended Smeltfest research trip.

Thursday, March 15, 2012

Forge Work at the Washington Cathedral

As the combined Smeltfest 2012 and research trip proceeds, I will only have spotty internet access - via my lap top. So postings may be less frequent and shorter...

Today I drove into Washington from Winchester, and spend most the day at the Washington National Cathedral.

Now this is an impressive building in almost every way. My intent on visiting was to examine the forged metalwork there, primarily by legendary artisan blacksmith Samual Yellen. Over the course of some four hours, I took over 120 images. These were both complete pieces, but also many close up details. Those images are the kind of thing that revel many things about the construction of the pieces, and individual shapes and processes used. Many discoveries!

These are just a couple of samples:

Around the main entrance to the Cathedral, there are a number of roughly 4 foot wide by 6 foot tall panels, all by Yellen. Each shows a distinctive design. This is a detail of the main fill of one of these. The heavy rings are held by a series of looped over elements, each end forged by splitting into a crescent. These are wrapped around the rings while hot. The end result is that each of the rings is actually free to move, making the panel slightly flexible.

This is a railing to one side of a set of stairs leading downwards to the 'crypt' level, this in the NE corner of the building. You can see the very organic lines. The hand rail on the opposite side of the stairs uses the same flat bar with double lines hammered in. The uprights and supports are quite different however.

This is the famous 'Good Shepard' gate by Albert Pailey. (Most all smiths would recognize it!) This is a view of the *rear* of the gate, not usually ever seen. To give you some idea of scale of this work, the majority of elements seen here are forged from starting stock that looked to be 1/2 to 5/8 thick - and four inches wide.

Tomorrow is a slower trip down to Lexington

Sunday, March 11, 2012

Demonstrating the Aristotle Furnace

Yesterday I undertook a demonstration / hands on session at the monthly meeting of the Ontario Artist Blacksmith Association. I had been part of the team that researched the working system for a small re-melting furnace (Smeltfest 2009). This is a simple to build small furnace, economical and fast to run. It will convert almost any iron based material (scrap, alloy, carbon content) into a small puck of bloomery like material with a mid to high carbon content. This allows someone to experience the unique textures of bloomery iron - without the effort and expense of a full sized iron smelt.

After an overview and demonstration of the process, I invited individual participants to run a furnace cycle and produce their own puck of metal. Seven individuals took part - with excellent results every time! The blade smiths gathered where particularly interested, as the application to their work was obvious.

Observing the furnace, near the end of a cycle.
Both these fellows would take turns making their own 'puck'.

I had prepared a short handout to distribute. As travel, timing (and luck) would have it, I was not able to get photocopies made in time for the demonstration. The handout is duplicated below. It will also be available as a PDF download. (Links will be placed on my regular blog, my iron smelting web site, and the OABA web site.)

The Aristotle Re-Melting Furnace

A simple way to make bloomery type carbon alloys

This furnace is based on the writings in Aristotle's "Meterologica' and later Ole Evenstad's descriptions in the 1780's.
The original concept belongs to Skip Williams, who then introduced a prototype to the Early Iron group a Lee Sauder's Smeltfest event in 2008. At Smeltfest 2009, our team concentrated specifically on the working dynamics of the Aristotle Furnace, with over 30 individual test firings.

The furnace is build like a miniature short shaft smelter. A standard 2 litre plastic pop bottle makes a good internal form. The ideal material for the walls is a 50 / 50 mixture of dry shredded horse manure mixed with powdered potter's clay.
A standard carpenter's pencil, or a piece of 3/8 rod is used to make the blast hole.
Critical measurements are :
1) the angle of the blast hole - at 20 to 25 degrees down from horizontal
2) the depth of the furnace floor below the blast hole - at 5 - 7 cm
3) height above the blast hole - at about 20 cm

A single firing consumes about 2 kg (standard galvanized pail) of charcoal over 25 - 30 minutes. The fuel should be broken to 2.5 cm or smaller, with dust screened out.

Temperature is determined by consumption rate, in turn modified by volume of the air blast. Ideal consumption is roughly 200 gms every 4 - 5 minutes (determined by timing a standard measure - a standard coffee holds about 200 gm)

The raw material can be almost any iron source. At first it is suggested that short lengths of standard 3/8 - 1/2 mild steel bars be used. Cut this into roughly 15 - 20 cm lengths, a total of 600 - 800 per firing.

Each bar is placed roughly 1/3 the distance back from the blast hole side, deep enough into the charcoal that the pieces hold it upright in place. The pieces are then allowed to descend as the charcoal level drops. Keeping the furnace full of charcoal, new bars are added as the previous ones drop below the upper surface. The last bar is covered with a last addition of charcoal, then the surface level is allowed to drop, burning the remaining fuel.

At this point a pointed hook can be inserted underneath the 'puck' of collected bloomery steel. It is a good idea to scrape out any slag that has gathered in the bottom of the furnace, then the whole can be re-filled with fuel for an additional process.

The result is a mid to high carbon metal, with the physical texture characteristics of bloomery iron. The created 'puck' typically weighs about 500 - 600 gms (65 - 75% yield). Once consolidated, this enough material to make two 4 - 6 inch long tanged knife blades.

Descriptions and further reading on the Web:

"Teeny-tiny Bloomery"
by Skip Williams

"A different way to make steel"
by Jesus Hernadez (on 'Don Fogg's Knife Forum')

Aristotle's Steel

by Lee Sauder (PDF download)

"Steelmaking in a tiny open furnace"
Donald Wagner (This is a photo essay from the same event that Lee's article above was based on.)

Part of the OAC Crafts Projects Grant

Tuesday, March 06, 2012

You Can't Always Get...

...what you WANT
(But if you try some times...)

(This posting an echo from Bloom to Bar)

This is a look at what happened yesterday in the forge.
If you check back to yesterday's posting. You will see that the concept I had come up with was to take one of the smaller, more compact looking blooms and layer it up on to a carbon steel core. The intent was to preserve the ragged edge into the finished object.

The bloom I chose for this was the one from Smelt 14 - at Dan Nickel's 'Folly at the Forge' event. (Black Rock Forge - Traverse City MI, February 2006. The story of that smelt is an interesting tale of endurance, it was 20 bellow F when we started!) The piece was a fragment at 485 gm off a much larger bloom. As we had forged down the full bloom to bars at the event, I knew the material was a 'nice workable iron' (from my notes).

As it was about fist size to start, it easily fit inside my two burner propane forge to pre-heat. This allowed me to bring the core up to temperature more slowly. Also allowed this process to take place while I was getting my main coal forge set up and started. All the actual forge work was done in the hotter coal fire.
(Note that I have altered this image in an attempt to get it closer to the actual colours you would have seen. The camera 'sees' down into the infra-red differently than the human eye does. The actual colour would have been a 'bright orange'.)
This is the end result of the initial flattening stage. I worked the raw bloom starting at a welding heat. I took two heats working with the hand hammer, concentrating mainly on the flatter of the rectangular sides. Then I took several heats on the air hammer, again starting with welding each time. The action there was primarily to draw the rectangle down to a wide and thin flat bar.
Here you can see the results after being cooled and cut into two fairly equal pieces. The loss from bloom to this stage (as you can see) was down to 394 gms

Thats a total loss of 91 gm, or about 20%.
The metal at this point still had some fissures in it, especially along one edge. If I was really trying to make a solid working bar, I would have collapsed the bloom into a square cross section, allowing me to work all four of the edge surfaces (instead of just concentrating on two). I would have undertook at least one more weld series. My estimate is that the total loss would have been closer to 25 %

The two bloom iron plates were roughly 1 3/4 inch wide x 3 3/4 long x 1/4 thick. I took a piece of standard 1045 middle carbon spring steel (new leaf spring) and placed it as a core. A working handle was MIG welded to the spring. I then tack welded the three pieces together at the far end. You can see that the central cut end of the bloom plates was placed at the far end.
(I normally wire together my starting layers. Also I like to weld from the far end back towards my body. Just habits!)
At this point there was a total of 643 gms of material, the stack was roughly 3/4 inch thick.You can see that the spring was a bit wider, at 1 3/4 inch. I left the plates all even on the 'cleaner' edge of the bloom pieces. (Remember a ragged effect was my initial goal.)

The finished result.
This billet is roughly 8 inches long (with the more or less pointed end) x 1 3/4 at the base x 3/8 thick. I have given it a fast surface clean on the high speed sander. Although there are certain to be some flaw lines, generally the surfaces are welded fairly tight.

Although this billet will certainly work up into a potentially quite nice blade, it is not quite 'what I need'.

Back to the pile for another attempt...

Saturday, March 03, 2012

Metal Stocks & Sizes Guide

Located in Owen Sound Ontario, Krueger Custom Steel may not be convenient for many reading this.
I have been purchasing from Krueger pretty much since they started business in 1994.

What has set them apart in my experience has been the acceptional level of service they have provided.
- They 'talk blacksmith' - understanding the (now old) British Gauge system as one good example
- Extremely reasonable 'local' delivery policy (less than the gas cost!)
- Good stock of standard sizes kept on hand
- Availability of specialized materials on order, usually within a week.
- Ability to provide cost quotes / order specifics via e-mail (so written down!)

At the Wareham Forge, my normal practice is to order in bulk, usually once a year for all my standard sizes. I am thus purchasing the smaller hot rolled, structural and pipe materials in multiple hundreds of feet. It is true that I might be able to get my order a wee bit cheaper at those volume levels from one of the larger industrial suppliers. Once delivery costs are added from major centres, that price advantage disappears.
Most importantly for me, the extremely high level of personal service I have always received from Krueger completely overweighs any slight cost savings.

What will be quite handy to the general member of OABA is a brand new feature available on their web site.
They have placed a complete metal stock guide available as a downloaded PDF. This kind of guide is invaluable for telling you just what sizes and materials are easily available. It includes 'weight per foot', which is handy for figuring out just what that wild idea of yours is going to total up at. (I've been caught by that one a couple of times!)

The Steel Guide PDF is available at :
Just hit the 'View Steel Book Catalogue' button at the top of the page

Krueger Custom Steel
1610 20th Street East
P.O. Box 187
Owen Sound , Ontario
Canada , N4K 5P3

Phone: 519-371-7930
TollFree: 1-888-244-4187
Fax: 519-371-7852

Thursday, March 01, 2012

All the Myriad PIECES...

(An echo from today's posting on 'Bloom to Bar')

Now that the layout table is not needed for the assembly of the hydraulic press (being modified specifically for this project), it was time to empty the milk crates full of blooms:

Click to *greatly* enlarge

Yesterday's work in the shop consisted of sorting all the pieces into historical order. Each piece was then photographed and weighed. There are over 60 individual pieces, ranging from full sized blooms (the largest at over 7 KG), down to small fragments. With luck even the small pieces can be welded as part of stacks towards creating layered steel billets.

I also spent a good hour attempting to work out some kind of useful method of measuring the volumes via water displacement. This in aid of determining the density of each bloom. This may not be critical towards artistic use of the individual blooms. However, keeping my archaeological slant in mind, once compaction and forging into working bars starts, the original density information will be lost. Better to record seemingly useless information - than work past it had find out later the data was significant.

Although I really have made a serious attempt to keep each bloom labelled, what I found was that the process of shifting around sharp edged metallic blooms had shredded bags and obscured labels. There are a number of pieces that obviously have been mis-labelled, a few (some of the largest!) with no labels at all. At least one distinctive bloom is missing from the pile.

I am attempting to keep notes relating the specific process used to create an individual bloom / bloom fragment to the compaction to bar process. Most specifically as it relates to individual carbon content and general ease of forging.

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

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