Roman Metalworking

[Gaius Colletti]

Is it really that impossible to believe that the Roman could make pottery (ceramic doesn't form until 2100 degrees) but were unable to melt iron completely (iron melts at 2700 degrees). Sure 600 degrees is a huge difference, but far from impossible

[Marcus Velius Avitus]

I guess it isn't so much a question of the base temperature, but the facility itself. A blacksmith can achieve a 3000 degree + fire in a rather little forge easily - which is what the Romans could do, but when you are taking raw iron ore and forming larger pieces it is best to have a LARGE environment as devoid of oxygen as possible to prevent oxidation of the iron(the instant oxygen hits it it forms scale on the surface at high temperatures). At least this is my (limited) understanding of it. This can create slag in the iron, which, when it cools will become "bubbles" or weak spots. This requires a specialized facility or set up. Any experts in Iron smelting out there care to correct or chime in on this?

[mcbishop]

You have to fell trees, split down lumber

Usually these processes were not needed. A lot of medieval charcoal was made from fallen timber or coppiced branches; the trees were left standing (don't know about Roman practices). Agreed with the rest of it. Charcoal makers regularly stayed awake for days at a time to keep an eye on the pile.

Exactly so. There is a tradition of managed woodland that goes back to the Bronze Age in Britain with archaeological evidence of coppicing etc from the Somerset Levels and elsewhere. Charcoal burning continued until the 1950s and has been revived on a small scale today in the Forest of Dean (one of the major ironworking areas in the Roman period). This tradition continued despite the fact that the Forest of Dean was (and still is, to a very limited extent) a coal-mining area. The two are not mutually exclusive and, even though coal was available, charcoal was made and preferred for ironmaking until the advent of coke.

Mike Bishop

[Crispvs]

"However, are you absolutely sure he said

he does not believe that Roman smiths had access to coal

...I have a memory of David saying they did not have coke at the Carlisle Millennium shindig..."


I am sure you must be right. You were sitting further forward in the room than I was and you will have spoken to him more recently than me (I last saw him two years ago when testing artillery, and that was the first time since the Carlisle conference). He probably did say coke not coal. Come to think of it, I now recall that the scale was case hardened on one side only rather than tinned and the suggested explanation he gave me was that scales had been placed back to back in carbon rich clay and baked.
I do remember having a very interesting conversation with Rob Travers during the break and I do distinctly remember how David Simm bristled when Rob Travers asked him about the possible use of coal in the production of the scale during the question and answer session following his paper.
Needless to say, I am quite sure David Simm knows a lot more about blacksmithing than Rob Travers, although Rob's wife Hillary (who used to post here as Claudia Crisis) is fairly clued up on iron production.
I, of course, know very little of these things and can only repeat what I hear and remember.
I will be looking forward to the new book in any case.



"Pah! He's a pussycat. You just have to know the safeword (fans of Serenity will get it)."

Hmmm - I have seen the film but I missed the beginning. Was the safeword something you could say to stop the reavers from attacking you?

Crispvs

[mcbishop]

I, of course, know very little of these things and can only repeat what I hear and remember.

Almost Herodotean ;-)

"Pah! He's a pussycat. You just have to know the safeword (fans of Serenity will get it)."

Hmmm - I have seen the film but I missed the beginning. Was the safeword something you could say to stop the reavers from attacking you?

At the risk of being thought even sadder than most people already believe me to be (which is pretty sad), safewords can be used as a backdoor in behaviour conditioning - in this case Simon uses one to stop River attacking anybody and anything in the bar after she sees the subliminal message - but the term can have another meaning altogether (I'll not link to the Wikipedia entry in case a prudish moderator disapproves). I believe there is one that stops most re-enactors talking about tunic colour... but I've never found it.

Mike Bishop

[ClaudiaCrisis]

Claudia Crisis did use to post on here but was not able to log on with the old password after the site was upgraded, hence I have been re-hatched (also as email adress changed so couldn't get that account active again).

Rob's work on Roman use of coal (based on his PhD thesis):
2008 ‘Coal in Roman Britain’, Bar British Series 468 (ISBN: 9781407302287).

At Carlisle, your memory was correct Crispus, it was "Coal" & not "Coke", hence the conversation between Rob & David Simm. We were actually sat immediately in front of Mike (although I don't think he noticed us).

[Ron Andrea]

So charcoal would have been used even when coal was available, but serious iron making would have been done (most likely) only at serious--read here: large, dedicated facilities?

I assume this iron would have been fine for horseshoes. Would it have been weapon quality?

[ClaudiaCrisis]

Coal is a frequent find on many archaeological sites, but is often not recognized – either ignored altogether or mistaken for charcoal, burnt wood, and on at least one occasion washed, numbered & recorded as black burnished ware.

The earliest recorded site in Britain where coal has been found in association with metal working dates to the late Iron Age (Long, 1988. 18 &20). The evidence indicates that coal may have been mined in the Forest of Dean and South Yorkshire. The earliest evidence for the use of coal in iron production in the South Yorkshire/Derbyshire/Lancashire/Cheshire areas was found at Hesley Park and Clifton Common.

Coal has been found at many Roman industrial sites, associated with all stages of metal production, from roasting, smelting (with some possible “blast” furnaces), through to smithing (where hearths appear to have been fuelled by charcoal, coal or a combination of the two). Some sites have been found with coal deposits associated with dedicated furnace types suggested to be specific to weapons and armour production (some of these being large-scale production facilities), including Wilderspool, Manchester, Templeborough, Little Chester (Derby), some also with features identified as quenching tanks for weapons/blade manufacture.

At Little Chester, excavations in 1979-80 produced evidence of coal in variety of industrial processes & large coal pile associated with a series of hearths & kilns.

Templeborough produced evidence of coal in variety of processes including pottery & iron production, in both the fort and the industrial annexe. At Templeborough evidence of early coal associated with iron production from the late Iron age was found associated with Phase I of the Roman fort, with the foundations of the earliest rampart (dating to AD 54) being based on deposits of iron slag and iron pan to harden the ground. These deposits may have originated either from a very early vicus or from an earlier Iron age settlement located near to the fort, in either event representing use of coal in iron production processes.


At Wilderspool, large quantities of coal, in the form of “Wigan Nut”, were found associated with the hearths and in some cases was mixed with charcoal. Coal was also found at Templeborough, Cantley, Rossington Bridge and Brough on Noe, associated with iron working activity. Coal is frequently found in association with smithing hearth slag, in pits, ditch fills and other contexts, indicating its extensive use in secondary smithing activity. Analysis of smithing slag from Brough on Noe was found to contain coal inclusions, indicating its use as the primary fuel.

More detailed information in:
Travis, J. R. 2008 ‘Coal in Roman Britain’, Bar British Series 468 (ISBN: 9781407302287).

[Gaius Colletti]

Wow Claudia, thanks for the info. You really are quite knowledgeable on the subject.

[Ron Andrea]

Claudia,

Excellent report. Thank you.

Mention of iron slag and iron pan in fortress foundations raises another question: Were smelting and smithing by-products used to underlay Roman roads? I remember references to "metalized" roads, but assumed they were a later phenomena (and can't find any references at the moment).

[ClaudiaCrisis]

Wow Claudia, thanks for the info. You really are quite knowledgeable on the subject.

Matt: Not Knowledgeable - just [strike]sleeping with[/strike] plagiarising the author. :roll:

Ron: If you get hold of the book, there is quite a lot on roads, along with other forms of transport infrastructure.

[Matthew Amt]

Uh, Ron, "metalled" is just British-speak for "paved"...

Matthew

[Ron Andrea]

Uh, Ron, "metalled" is just British-speak for "paved"...

Matthew

G. B. Shaw (or Oscar Wilde or Winston Churchill ) alled us two nations separated by a common language.

[richsc]

The same Mr. Sim, I note.

[richsc]

they did not have coke at the Carlisle Millennium shindig

No coke, Pepsi.