Friday, July 28, 2006

"Reforging Iron in Pictish Scotland 850-1050AD

A version of a recent request and my reply...

Evelyn wrote:
"... I'm researching a novel that's set in the Aberdeen to Inverness area of Scotland around 850-1050AD with Vikings, Picts and Monks as characters.
... The author has asked me to find out what the process would be for a Viking youth in Scotland (who has been exposed to iron smithing techniques in Norway) to turn an iron candle sconce into a blade during this period."

Ok - the first main point is that you are looking at the skills of the blacksmith. There should be some information available on-line in a general sense here. DARC will have some images from our presentations at Heffenreffer in Rhode Island of a reconstructed Viking Age sand table style forge. The smithing equipment seen is largely based on the Mastermyr tool box. That collection is from Gotland, and although dated to 1150 contains all VA type tools. Check also the information on the Norse Encampment - under Artifacts

Second point relates to the candle sconce. Not really a Viking Age type of object. Its also likely to be a very bad choice in terms of its starting shape related to the desired finished knife shape.

The details I require are:
> What kind of tree was used to make the charcoal? (I've read the wareham forge page which says that types of wood didn't matter)

Exactly. Archaeology shows that charcoal used compares exactly with what ever trees were growing locally. I doubt peat would work. (Although I have heard rumors of attempts to use this.) Coal was not used until into the 12- 1300's. Hardwood works better than softwood. The thermal energy is similar pound per pound, but the hardwood requires less volume and keeps its shape longer. Oak would be one of your better choices if available. (At L'Anse aux Meadows they used the local black spruce and birch.)

What was the tree chopped down with?

Seriously? An axe...

How was the wood obtained from the tree?

Most likely just cut the whole thing down and render it into pieces. I think you may be hinting at the possibility of gathering wind fall branches. This is less work than cutting down whole trees, but really only is effective in a mature forest. Later in the Middle Ages they would coppice - grow a small plot of fast growing saplings set very close together. This gives a quick turn over of similar sized trunks, and is ideal for commercial production.

In any case, the manufacture of charcoal is its own lengthy process. The wood should be cut down or split to roughly identical diameter pieces. In the Viking Age, the most common method was to dig a shallow, wide bowl and then construct a bee hive shaped pile of wood splits - say 2 - 3 meters across and about 2 meters tall. Over the wood goes a layer of grass sods and earth. A hole is left in the top and a couple of holes at the base. Set the stack on fire. Once the burn is established, start blocking the holes with stones. Trick is to allow enough air (oxygen) into the inside to maintain a slow smoldering fire. Too much air and your just burn the wood to ash. Too little and there is not enough heat maintained to bake the wood to charcoal. This process can take days to accomplish. Once the pile stops off gassing heavy smoke the charcoal conversion has taken place. You would block all the holes, let the interior cool and then open it up.
The resulting charcoal would then have to be broken up to use in the forge. My own limited experience here suggests pieces from walnut to fist sized for the forge.

How did they store and dry the wood?

Ah - for making charcoal you want to use the wood 'green' - fresh cut. Saves that whole problem.

> Did they use a crucible to heat the iron object?
> What was the crucible (or similar) made of?
> What did it look like?

No - you are thinking of CAST iron, which was not used in any form at all until well past the Medieval period. The VA blacksmith would be forging his metals - heating and hammering them.

What else was required in the process?

VA forges are distinctive in that they use a block of stone, usually soapstone, to bank the fire up against. This specially made bellows stone has a hole in it that has the bellows attached on the other side.
Forges are often shallow bowls on the ground.
VA bellows are a distinctive double bag style. See the image on the web site for reconstructions.
Anvils in the VA are quite small. Typical is a rough cube about 10 cm to a side and maybe 5 - 10 kg. It is also possible to use a large flat rock.
There is some discussion about how an anvil would be mounted. This relates back to the body position that the smith would work in. Could be kneeling, hunkering or standing. A timber block to set the anvil on would be cut to the required height.
A good reconstruction of a VA blacksmith's shop can be found inside my exhibit 'World of the Norse'.

Could one person carry out the procedure?

Well - if you have to. Ideally there should be a second person (often a child or apprentice) pumping the bellows. The arrangement of the equipment makes it difficult to work the bellows then rush over to grab the metal to hammer it in the short time it is a working temperature. Charcoal also burns away quite quickly so the metal needs to be constantly re-positioned in the fire. The effective heated area in a VA forge is about 10 cm diameter at best.

What did they do to make it into something?

If starting from a normal 'currency bar' of wrought iron (a piece roughly 2 x 2 cm by about 20 - 30 cm long)
- draw source bar out into starting profile (for a knife something like 3 cm wide by maybe .5 cm thick by however long.
- forge the object
- see blade smithing below

> What tools were used to work the iron?

- hammer (roughly 800 - 1000 gms by the way)
- tongs

How blacksmiths worked?

No idea what you mean here. Obviously this is an open ended question that covers several books worth of description - or a lot of years at the forge. I'd suggest you track down one of the Medieval or Viking Age re-enactors in your area and ask if there are any working smiths in the group. I do know there are several in Australia. Watch them work. Also consider purchasing my own DVD 'Forging the Viking Age', which details production of a number of VA objects (admittedly using Victorian equipment).
The key is that forging takes a block of material and stretches it. No mass or volume is added, but some will be lost depending on how extensive the forging is. - see the bit below about clay

What problems would a novice encounter reforging iron?

Technically, any wrought iron object can be re-forged into a different shape. The problem lies in how easy it is to convert one shape into another. The more complex the shapes involved the more difficult this will be.
- A fast way to gain insight is get some clay and make a soft clay version of object one. Then try to squish that shape over into object two.
Any time you attempt to fold the clay - it's a forge weld. This is challenging to accomplish with a VA charcoal fire - and not work for beginners in any case. The odds are good a beginner would overheat and destroy the metal - or underheat and not get the weld to stick (more likely actually with this VA forge set up) Also expect to loose maybe 10% of your metal mass at each full weld step.

How difficult is it to make a blade?

Bladesmithing has its own problems. The metal you start with should be of different quality - higher carbon content - than what is used for everyday domestic pieces.
- see above. Effective bladesmithing also requires careful control of the hammer to produce an even stress on to the shape as it is forged out.
- After the shape is forged, it must then be polished. In the Viking Age, this would be done mainly by grinding the surface with hand held stones. This will take MUCH longer than the forging process. (Days instead of hours).
- Next comes the three steps of the heat treating. Anneal to soften and releave stresses. Harden by quenching. Temper to soften the blade slightly to give it the required flexibility in use. This was a 'mystery' and would not be discussed outside of the smith / apprentice relationship.
- Finish with applying the handle.

What would be involved in progressing from a blade to a sword?

In theory you could take several small knives and reduce them to flat bars. Weld the flat bars together to a larger block. Take that block and forge it out into the sword shape. Undertake all the polish, heat treat and hilting steps.
Now double all the difficulty due to the size of the object. Four times the difficulty for the heat treating. For the Viking Age equipment (forge and anvil size) increase difficulty by at least four times.

It might make more sense to consider taking several smaller objects of smaller size and various types and forge welding these into a layered steel billet. Again refer to the wareham forge site (bladesmithing) for a fast description of pattern welding. In its simplest form (often seen in the VA) use the harder metal from a knife as the centre with two outside slabs made from wrought iron from a meat skewer. Remember that a REAL sword weighs something about 1 kg. You'd need about a kilo and a half of metal to start (loss in welding and polishing).

Remember that the 'average metal load' per person in the Viking Age is in the range of 2 kilograms. (Modern North Americans have closer to 1000 kg or more!)
Generally swords are expensive objects - and highly specialized ones. They were often family heirlooms, and certainly not every male owned one. Multi function tools like axes or spears were far more common. The smiths who created them were also specialists. Pattern welded swords were the product of master smiths alone. Although your young hero may have been able to pound a straight section of metal from a cooking tool handle into a simple knife - if he had access to that axe to make the charcoal he would be more likely to just re-sharpen the axe and use it on his adventure.

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