Wednesday, December 11, 2013

Knifemaker Interview - Part 2 B

Some apologies for the double posting - I'm having some connection problems.
Direct satellite uplink system here. Maybe early into the internet, but the rest of the world caught up and passed us rural folk here in Ontario.
This reflects back on something a couple of you mentioned - about visibility on the internet. Although I hardly am located in the 'back of beyond' (two hours drive NW of Toronto), it is a good 14 hours drive from 'Smelt Central' (Lee Sauder's in Lexington Virginia). The great strength of the internet is it allows so many of us 'on the margins' to participate directly with many scattered other people who we might otherwise never personally meet. Glimpsing finished work through those carefully selected (photoshoped?) images is never quite the same as holding a blade in your own hands...

Part 2 - She said, He said...

As I hinted in the last entry, the standard interpretation of the available archaeology as published by AS Ingstad was this:
There was a major boat repair (number of rivets)
This was a single repair event (location of fragments)
Weight of needed rivets equals estimated iron production
Therefore - A major repair was needed, so the Norse 'simply' smelted the iron needed

This was the standard information communicated by Parks Canada at the site.
When I first started working on the living history program there, I had a number of (friendly, sometimes over drinks) discussions with Dr Wallace about this.
My main discussion points / objections:
- Leif Eirikson was a second generation, professional, expedition leader. I just could not imagine that he would even remotely consider heading out into the unknown without taking along a bag of boat repair rivets. (Note that it is almost as far to sail from the Greenland settlement to LAM - as it is to sail back to Norway!)
- The evidence points to only a small boat being repaired. (The width of that 'garage' is less than 2 metres.) NOT a full sized, ocean going 'knarr' hull. Given the lack of building timber in Greenland, certainly valuable - but not what is getting you home from Vinland.
- How easy is it *really* to make iron? Was this general or specialized knowledge and skill? Would the Norse realistically expect to be able to smelt iron 'just anywhere'?
- What about the metal tools required to effectively make iron? If you were stuck needing a ship repair to get back home, would you not give up a sledge hammer (needed for bloom compaction, weight 3 - 5 kg) to make an emergency supply of rivets?

Those last two points were always the critical ones for me.
Most of you have noticed that the archaeologist's reports make a direct link from the 'production' estimate of 3 kg with a known weight in discarded rivets at 3 kg.

One question as a metalworker:
Might it not be a lot easier just to attempt to re-weld up those rivet pieces into some new source bars?
Now, I certainly have never personally tried this kind of thing. The pieces would certainly be heavily corroded, and that likely would really complicate any attempt to do this. (Those reading who have welded up cycle chains to billets might have observations?)

Clearly, the archaeologists missed entirely that a bloom is *not* a working bar.
Again, I don't think there is any good published information on this process. I certainly do not feel I have accumulated enough experience (much less documentation in terms of measurements) to offer any solid numbers. I think the best I have ever managed has been about a 20 % loss from bloom to bar.*  (I will hope that some of you who work extensively with bloom iron will comment here!)
Any way you look at it, a 3 kg bloom does not equal 3 kg of finished rivets!

And just how good were those original Norse at the iron smelting process to begin with?
If you hold to the 3 kg bloom from that 18 kg of (good) ore - this is only a 17 % yield!
Not withstanding this is a small volume smelt and these usually produce lower yield numbers.

Honestly folks, when we undertook our demonstration smelt at LAM in 2010, I was kind of embarrassed by our own low return, at about 14%. (We got a fairly crumbly 2.8 kg bloom)
Mind you - after Birgitta had watched the amount of labour (all human powered air) and general rushing about (we had some burn through problems with the furnace) on that demonstration, she told me she had revised her opinions about just how 'simple' producing iron was for the Norse.

(for a more formal discussion of all this - go to my paper 'An Iron Smelt in Vinland - an experimental investigation')

I have always felt the iron smelting process was a specialist task. The general archaeology from the Viking Age places the iron smelting process as physically removed from the community in general. It is *ore* which is dictating the location of the production. Iron was (generally) smelted at remote locations, then either transported as compressed cakes or rendered down into fairly standard bars for sale to the actual blacksmiths. (So standard that these are known as 'currency bars'.)
The Norse are largely a society of reasonably isolated, large farmsteads. It is common for each to have at least a separate 'smithy' building. (Although how much and how often this might have been in operation is an open question. A well rounded 'occasional amateur'? Seasonal use by an intinerant professional smith?) The situation for iron smelting may be different in these locations.

But increasingly during the Viking Age, there is the development of trade based towns. (And this leads back to something you had mentioned Shel.) Here craftsmen are working in combination workshop / residences. Producing work for direct barter, or more and more, for sale against silver coins. (Just where all that 'Danegeld' was going!) These working blacksmiths are purchasing themselves the required raw materials for their trades. In this case the charcoal fuel for the forge and the iron working bars they need to produce objects.

So I guess that leads us (finally) back to the blacksmith - and bladesmith...

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

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