About hammerscales :

One question is the identification of 
hammerscales in an archaeological sediment. And 
indeed, a simple magnet is the easiest and more 
efficient way to make this qualitative 
observation.
To quantify the presence of hammerscales is a 
much more difficult question. There are several 
trials based on magnetic susceptibility 
measurments. This method gives interesting 
results. Another efficient approach is the 
systematic collection of sediment samples, 
followed by washing and seaving and systematic 
collection of the magnetic residues using a 
magnet. But there are some biais introduced in 
this type of procedure because the recovery of 
the hammerscale is depending on the grain size, 
the humidity of the sediment and the type of 
magnet used (and probably many other factors).
I personnaly make the observation that the 
magnetic residues issued from washing and seaving 
can contain up to 20% of non-hamerscale material 
after study under the microscope.

Another question is : Is it possible to relate a 
given type of hammerscale to a given type of 
smithing activity (i.e. welding, bloomsmithing, 
low temperature hammering, and so on) ?
As far as I know, until now, few work has been done in this direction.
The PhD work of Jean-Claude Leblanc at the 
university of Toulouse 2002 (in French) is an 
interesting first step but with limitations (use 
of modern iron, etc)
It is well known that different types of 
hammerscales (flakes, irregular flakes, empty 
spherical and sollid spherical, etc : see Allen 
1986). But little is known about the ratios 
between those groups in archaeological samples.
On the other hand, one must be aware that the 
hammerscales accumulate during the total duration 
of the activity of the workshop (even during one 
single process of production, the assembalge of 
hammerscales change during time). The 
archaeological sample is then a composite 
assemblage.
Nevertheless, it can be very interesting to 
contrast samples from different locations at one 
site, maybe to locate area for specific activity 
and so on.

Vincent Serneels

>There is 1 message totalling 72 lines in this issue.
>
>Topics of the day:
>
>   1. hammerscales
>
>----------------------------------------------------------------------
>
>Date:    Fri, 14 Mar 2008 18:57:33 -0000
>From:    "BAYLEY, Justine" <[log in to unmask]>
>Subject: Re: hammerscales
>
>Heather
>
>The best way to detect hammer scale is to use a magnet. The scale is
>tiny flakes and spheres (diam ~0.5-2mm) that are strongly magnetic and
>will stick to your magnet - so put it in a polythene bag first!. See Fig
>19 (and also Figs 5 and 20) in=20
>Bayley J, Dungworth D and Paynter S 2001, Archaeometallurgy (London: EH
>Guidelines 2001/01) which can be downloaded from the Web:=20
>http://www.english-heritage.org.uk/upload/pdf/cfa_archaeometallurgy2.pdf
>There's also a published paper that describes the form and formation of
>scale:=20
>Unglik H 1991a, 'Observations on the structures and formation of
>microscopic smithing residues from Bixby Blacksmith shop at Barre Four
>Corners, Massachussetts, 1824-55', Historical Metallurgy 25(2), 92-98.
>There are various publications that have used hammerscale distributions
>to identify and plan smithies. Do get in touch if you want further
>information.
>
>Best wishes
>Justine
>=20
>Dr Justine Bayley
>Hon Editor Historical Metallurgy=20
>English Heritage
>Fort Cumberland
>Eastney
>Portsmouth  PO4 9LD
>=20
>Phone: +44 (0)2392-856794
>Fax: +44 (0)2392-856701
>[log in to unmask]
>=20
>
>-----Original Message-----
>From: Arch-Metals Group [mailto:[log in to unmask]] On Behalf Of
>Heather Snow
>Sent: 13 March 2008 20:30
>To: [log in to unmask]
>Subject: hammerscales
>
>Is anyone able to suggest what would be the best analytical method to=20
>determine whether or not I have hammerscales? I understand that these
>are=20=20
>the remnants of an oxide scale formed on the iron billet during primary=20
>smithing, but is there something characteristic about their chemistry or
>
>microstructure that can aid in the identification process? And if so,=20
>which is the most sutiable analytical technique to use?
>
>Thanks,
>Heather Snow
>
>___________________________________________________________________________=
>______
>This e-mail (and any attachments) is confidential and may contain personal =
>views which are not the=20
>views of English Heritage unless specifically stated. If you have received =
>it in error, please delete it
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>
>------------------------------
>
>End of ARCH-METALS Digest - 13 Mar 2008 to 14 Mar 2008 (#2008-29)
>*****************************************************************


-- 
Vincent Serneels
Earth Sciences
Department Geosciences
University of Fribourg
Chemin du Musée 6
1700 FRIBOURG - Switzerland
tel. +41 / 26 / 300 89 31
fax. +41 / 26 / 300 97 42
[log in to unmask]
www.unifr.ch/geosciences/geology