Conservation of Copper

7/21/2019 Conservation of Copper

1/103

Review of copper corrosionproducts:

Copper chlorides (CuCl, CuCl2,

etc.).

Copper oxides (Cu2

O, CuO,etc.).

Copper sulphides (Cu2S, CuS,

etc.).

Copper sulphates(Cu4SO4(OH), Cu!SO4(OH)4,

etc.).

Copper phosphates (Cu2("O4)

(OH), etc.) Co er car#onates $%a&e courtes' of avid . Scott.

Conservation of CopperConservation of Copper


2/103

Shiva, *ord of the

ance +th-++thC .Shiva as creator,preserver anddestro'er of the

niverse. $n the creation of

#ron/e patina, hasShiva created a

chaotic, rando%,structured, or la'ered%orpholo&' ofalteration productswith ti%e, or has the

o#0ect #een destro'ed

ncient etals 3echnolo&' Structurencient etals 3echnolo&' Structure

Courtes' of the rt $nstitute of Chica&o.


3/103

Shipwrec5 #ron/e 6nds$%a&e courtes' of 3he 7ictorious 8outh.

9od' parts of #ron/e statuesof various dates. ound in

the driatic Sea near 9rindisi


4/103

$%a&e courtes' of 9ri%#leco%#e +;; and avid . Scott.

Mineral

name

Formula Crystal system Color Mohs

hardness

Cuprite Cu2O Cubic Submetallic red 3.5 4

Tenorite CuO Monoclinic Metallic gray black 3.5

Spertiniite Cu(OH)2 Often amorphous Blue green 1 2 ?

Characteristics of some copper oxide and copper hydroxide minerals: the most

common is cuprite

eterioration of Coppereterioration of Copper


5/103


Mineral name Formula Crystal

system

Color Mohs

hardness

Malachite CuCO3. Cu(OH)2 Monoclinic Pale green 3.5 4

Azurite 2CuCO3. Cu(OH)2 Monoclinic Vitreous blue 3.5 4

Georgeite CuCO3. Cu(OH)2 Monoclinic Pale blue ?

Chalconatronite Na2Cu (CO3)2. 3 H20 Monoclinic Greenish blue 3 -4

Rosasite (Cu, Zn)2CO3(OH)2 Monoclinic Bluish green 4.5

Aurichalcite (Cu, Zn)5(CO3)2(OH)6 Orthorhombic Pearly pale green 1 2

Claraite (Cu, Zn)3(CO3)(OH)4.

4H2O

Hexagonal Translucent blue 2

Characteristics of some basic carbonate minerals: the mostcommon are malachite and azurite



6/103

3'pes of treat%ents echanical cleanin&: local


7/103

Types of environments

"roducts for%ed durin& #urials.

"roducts for%ed durin& exposure to theat%osphere.

"roducts for%ed inthe indoor %useu%environ%ent.

"roducts for%ed in%arine conditions.

"roducts%anufactured foruse in patinationor as pi&%ents.

$%a&e courtes' of avid . Scott.



8/103

Statue of 7ictorious 'outh, Aree5, c ! 9C. Hollow cast #ron/e

with copper inla's, #efore %echanical cleanin& and conservation(left)and after (right).$%a&es courtes' of the Aett' useu%.

Bronze cleaned by

hand, loose left

arm removed, clay

core partially

removed,

immersed inheated sodium

sesquicarbonate,

then vacuum

treatment, then

distilled water, with

periodic exposure

to high RH. When

bronze stabilized,

arms reattached,

two stainless steel

bars inserted,

synthetic resin

used to attachmodern armature

inside nec,

shoulders, upper

arms and right

nee.


9/103

Often a co%#ination of various corrosionproducts, #ut we still &et a reasona#le Bori&inalsurface to clean to. So%eti%es in #ron/es this

surface is associated with tin oxides which arever' insolu#le.



10/103

Dhou 'nast' &ui, #ron/e, shown durin&treat%ent with cleaned section on the ri&ht.

$%a&e courtes' of reer Aaller' of rt, Eashin&ton, .C.


11/103

Ee %a' &et disruption to the Bori&inal surface

created #' diFerent products or events, such aschloride ion pittin&.




12/103

3he 7ictorious 8outh3he 7ictorious 8outh

Statue found in

driatic Sea afterstor% in +;Gs.ot new whenori&inall' lost at

sea. 3he surface which

can #e revealed #'cleanin& is

varie&ated andco%plex.

$%a&e courtes' of 3he 7ictorious 8outh.

Statue of 7ictorious 8outh(detail), pro#a#l' !rdI2nd

centur' 9C. 9ron/e with copperinla's, Aett' useu%.


13/103

Ee %a' loose coherence in so%e o#0ects whichnow have the stren&th of a hard #iscuit as%assive alteration to cuprite occurs.



14/103


Courtes' of 9ruce Duc5er%an'.

Cuprite below malachite crust extends through sheet


15/103

7er' heav' %inerali/ation of the Copper eadSea Scrolls seen in section. 3he &reen is%alachite and red and oran&e cuprite.

3her%od'na%icall' sta#le #ut %echanicall'unsta#le.



16/103

ncient 9ron/encient 9ron/e

an& *ei +2>++ c 9C.

*ate Shan& +J-+?9C

oes the surfacerepresent the ori&inal

patina, su#se=uentcorrosion. Or aco%plex of #oth1

Ehat do we want our

#ron/es to loo5 li5e1 s the' were

ori&inall' or as foundfro% #urial orcleaned1

Courtes' of the rt $nstitute of Chica&o


17/103Eestern Dhou 'nast' hu$%a&e courtes' of reer Aaller' of rt, Eashin&ton, .C.


18/103


"ure copper reddish, #ut

colour of Cu-s and Cu-Sn&olden so colour %a' #ei%portant.

Ehole variet' of ancient

copper allo's used: Cu-s,Cu-S#K Cu-iK Cu-&K Cu-Sn,Cu-DnK Cu-Sn-Dn, Cu-"#, Cu-Sn-"# etc.

3his &iant 9uddha ? feettall, cast in sections insli&htl' diFerent Cu-Sn-"#allo'.

Eeathered to #rochantitepatina: no allusion to &oldenAreat 9uddha, +2?2, Loto5u-in 3e%ple,La%a5ura, Mapan. Hollow #ron/e. $%a&e courtes' of avid . Scott.


19/103

Chinese investi&ations

into ancient #ron/e hadalread' #e&un #' the+th-++thcentur' ,predatin& such wor5 inthe Eest #' N 'ears.

u%erous recipes fro%

the Son& and in&periods atte%pt torecreate the appearanceof Chinese #ron/es whichwere alread' twothousand 'ears old when

Aao *ian , a in&collector records anarti6cial patina #e&innin&with sal a%%oniac, alu%,#orax and #a5in& it.atthe end of a ver' lon&

recipe he ends #' sa'in&Bthat such patinas cannot

ncient 9ron/encient 9ron/e


20/103

etals: 9ron/es of Areeceetals: 9ron/es of Areece

$%a&es courtes' of the 3oledo useu% of rt.

3he %a&ni6cent #ron/es fro%

Riace fro% ?th

C 9C. ound in sea near Cala#ria in

$onian sea. .

a' have #een #lac5patinated #ut this could #e

fro% sea #urial. Conserved with eccentric 9J

%ethod usin& a%%onia in%ethanol followed #'h'dro&en peroxide in

%ethanol and RH testin&, air-a#rasive cleanin&, RH testin&,local treat%ent with 93 inethanol, onl' three areaslac=uered.


21/103

"atina"atina

Ee now 5now that #lac5

patinated #ron/es were a luxur'ite% in the ancient world. Lnowled&e of such allo's see%s

spread fro% China and Mapan toancient


22/103

Ro%an #ron/e pla=ue &r+;J;.+2-+!.+#lac5 patinated with &old and silver

inla' Courtes' of 9ritish useu% Ro%an to&ati Courtes' of Aett' useu%

So what was Corinthian #ron/e1 3heapocr'phal stor' retold #' "lin' wasthat a house #urned down in Corinth%eltin& the #ron/e, silver and &old ofthe owner to&ether %a5in& anattractive allo' with dar5 patina.$nlaid #ron/e da&&ers fro% 'cenae

have #lac5 panels set into the sideswhich are the%selves inlaid in &oldand silver. t'pical co%position is;!@ Cu, ?@ SnK +.J@ &old, .?!@silver and .?@ arsenic. 3he


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3he elphi Charioteer



24/103

elphi Charioteerelphi Charioteer

"lutarch writin& in 2ndC

a#out the #ron/es ofelphi: 3he elphic air isdenser and close oftexture, with a tensioncaused #' the reectionfro% the hills and theirresistance, #ut is also 6neand #itin&.this 6nesseallows it to enter the#ron/e, and to scrape upfro% it %uch solid rust,

which rust a&ain is held upand co%pressed..thescrapin& up of the rust isnot the onl' purposeserved #' the 6nesse of

the airK it also %a5es thecolour itself %ore leasant $%a&es courtes' of 3he useu% of nti=uities, thens.

i i f C


25/103


Agency

a

Soil type Years Corrosion(m/year) Maximum pitting(mm/year x 104)

BNFMRA 5 least corrosive 10 0.5 - 2.5 Uniform: no pits

BNFMRA 4 least corrosive 5 5.0 - 25 0.040

NBS 9 least corrosive 14 4.0 - 2.5 0.043

NBS 2 next most

corrosive

14 25 130 0.033

BNFMRA Acid clay/acid peat 10 53 66 0.046

BNFMRA 2ndseries:bcinders 5 66 0.32

NBS 3 most corrosive:

rifle peat/

tidal marsh

14 160 355 0.115

Analysis of corrosion of soils

aBNFMRA = British Non-Ferrous Metals Research Association (now defunct); NBS = National Bureau of Standards.

b2ndseries = second attempt to derive accurate results for this set of data.



26/103

$%a&es courtes' of avid . Scott.

3wo s%all penannular #ron/e nose orna%ents fro% the site of *aCo%pania,


27/103

9ron/e isease9ron/e isease$%a&e courtes' of the Aett' useu%.

iniature "ortrait9ust of a Eo%an,

Ro%an, 2? 9C - 2?. 9ron/e with&lass-paste inla's.3he #ust is shown#eforeconservation,illustratin& pustular

corrosion withpittin& created #'#ron/e disease.


28/103



29/103


e


30/103


Mineral name Formula Crystal system Color Mohs

hardness

Nantokite CuCl Cubic Pale green 2.5

Atacamite Cu2(OH)3Cl Orthorhombic Vitreous green 3 - 3.5

Paratacamite Cu2(OH)3Cl Rhombohedral Pale green 3

Clinoatacamite Cu2(OH)3Cl Monoclinic Pale green 3

Botallackite Cu2(OH)3Cl Monoclinic Pale bluish green 3

Anarakite (Cu, Zn)2(OH)3Cl Rhombohedral Light green 3

Characteristics of some copper chloride minerals



31/103

eterioration: 9ron/e iseaseeterioration: 9ron/e isease

Alteration of cuprous chloride

to one of the coppertrihydroxychlorides.

4CuCl + H2O + O2=

2Cu2(OH!Cl +2HCl

2HCl + Cu2O = 2CuCl + H2O

2HCl + 2Cu = CuCl + H2

"ossi#ility of extensive or

continuous deterioration dueto acidic conditions andchloride ions.


32/103




33/103



34/103

9ron/e isease: 3reat%ents9ron/e isease: 3reat%ents

=ueous sodiu% ses=uicar#onate %ethod. Scott(+;2+) used ?@ a=. aHCO!.a2COa:

has a pH+K nanto5ite unsta#le, converts tocupriteK h'drochloric acid released.

co%#ines with car#onate to for% sodiu%chloride, which can #e washed out.

ethod still in use in 9 in +;J.

3oo %uch potential patina alteration.


35/103

9ron/e


36/103


37/103

eterioration: 9ron/e iseaseeterioration: 9ron/e isease


38/103

$%a&e courtes' of avid . Scott.3o&ati pustule


39/103



40/103



41/103


echanical cleanin&

"artial cleanin& of a #ron/e Aer%an to5en


C i f CC ti f C


42/103

echanical cleanin&



ConservationConservation


43/103

echanical cleanin& of ato&&le pin.

3oo %uch1

ConservationConservationof Copperof Copper


i fC i f C


44/103

echanical vs.


45/103

9en/otria/ole (93)

eposits &rowin& on Copper allo' o#0ect durin& 93treat%ent.



$ i i f i #$ ti ti f i t #


46/103

0ureite corrosion on a

#ron/e vase fro% theOriental $nstitute ofChica&o.

Cu+.;S

$s this da%a&e fro%corrosion in stora&e or isit a natural patina of the#ron/e vessel1

Ee can &et sulphidesfor%in& fro% poor stora&econditions or as naturalpatina constituents.

Courtes' of Susan Stoc5

$nvesti&ations of ancient #ron/es$nvesti&ations of ancient #ron/es

t i ti f C t i ti f C


47/103

Sulphides often fro% anaero#ic environ%ents

where sulphate-reducin& #acteria active. Cancreate ver' stran&e patinas as coin here shows.

Right:Ro%an coin excavated in +;N fro% theriver 3ha%es

Below:edieval copper allo' 5e' excavated in+;N+ fro% the river 3ha%es.





48/103


Mineral name Formula Crystal system Color Mohs

hardness

Anilite Cu7S4 Orthorhombic Metallic bluish gray 3

Chalcocite Cu2S Hexagonal Metallic blackish gray 2.5 3

Covellite CuS Hexagonal Submetallic blue 1.5 2

Digenite Cu1.8S Rhombohedral Blue/black 2.5 -3

Djurleite Cu1.96S Monoclinic Metallic gray 2.5 -3

Characteristics of some basic copper sulphide minerals



49/103


Marine zone Environment Characteristic behavior of copper

Atmospheric Small sea-salt particles carried by wind.

Corrosivity varies with height above

water, dew cycle, bird droppings, wind,

etc.

Partially sheltered surfaces may deteriorate

more rapidly than those exposed; top

surfaces may be washed free of salt by rain.

Splash Wet, well-aerated surface, no fouling. Most aggressive zone for may metals and

for protective coatings.

Tidal Marine fouling present to high water. Copper may act cathodically at tidal zone.

Shallow water Seawater saturated with oxygen;

pollution, sediment, and fouling may all

be present.

Corrosion may be more rapid than in

exposed marine zone areas; a layer of hard

shell and biofouling may restrict corrosion.

Continental shelf No plant fouling; some decrease in

oxygen, especially in the Pacific, and at

lower temperatures.

Copper alloys may be well preserved.

Deep ocean Oxygen varies, lower here than atsurface; temperature near 0C; velocity

and pH both lower than at surface.

Data for copper alloys sparse, butcorrosion is limited.

Mud Sulfate-reducing bacteria present;

bottom sediments vary in origin,

characteristics, and corrosion behavior.

Partially buried bronzes corroded most;

submerged copper alloys may be severely

attacked.

Typical marine environments

C ti f CC ti f C


50/103


BRapid shipwrec5 coin

3reated for 4 wee5s in 2@ sodiu%ses=uicar#onate




51/103


Surface corrosion containin&

pustules of copper and leadsalts.

Surface of the Ro%an #ron/estatue of Ro%a or 7irtusshowin& 6#rous %alachiteoccurrin& as curled cr'stals.


C ti f CConser ation of Copper


52/103




53/103

How to treat suchsurfaces1




54/103

"lot showin& the solu#ilit' of diFerent coppersulphate and oxide species in dilute sulphuric acidsolutions. ata #ased on ther%od'na%ic andother calculations at 2?C,after attson and Araedel.Dones for acid rain and fo&

are displa'ed, overlapsindicatin& which %ineralsare li5el' at particular pHlevels and sulphateconcentrations. 3he leftside shows no sta#le%ineral for%s, onl'CuTTin solution.

$%a&e courtes' of ndrew *ins and 3rac' "ower


eterioration ofeterioration of


55/103

Sta#ilit' dia&ra% ofthe s'ste% Cu-SO4-H2O with fo& and rainareas shown for ur#anat%ospheres. rea

U ataca%ite sta#ilit'Karea 9 U #rochantitesta#ilit'. lthou&h thedia&ra% over-

si%pli6es the actualsituation, it does showthat #rochantiteshould for% inoutdoor exposure an

that antlerite %a' $%a&e courtes' of Araedel +;NJ and avid . Scott.

eterioration ofeterioration ofCopperCopper



56/103

9en/otria/ole (93)

eposits &rowin& on Copper allo' o#0ect durin& 93treat%ent.





57/103

0ureite corrosion on a

#ron/e vase fro% theOriental $nstitute ofChica&o.

Cu+.;S

$s this da%a&e fro%corrosion in stora&e or isit a natural patina of the#ron/e vessel1

Ee can &et sulphidesfor%in& fro% poor stora&econditions or as naturalpatina constituents.




58/103



59/103

3he copper sulphide

corrosion has acauliower-li5e%orpholo&' whenseen close-up.


9ron/e Ro%a with unusual surface9ron/e Ro%a with unusual surface


60/103

9ron/e Ro%a with unusual surface9ron/e Ro%a with unusual surface


Hexagonal network structure

Within patina. Tin oxide

enriched



61/103

3he site of rancavilla

$%a&e courtes' of 9olletino dGrte.

ro% left to ri&ht,top to #otto%:V


62/103

How to treat suchstrea5in& and pittin&

Conservation ofConservation ofCopperCopper




63/103

ConservationConservationof Copperof Copper

$%a&e courtes' of

www.culture.&ouv.fr>culture>archeos%

3wo #ron/e swivel &uns have #eenrestored #' rchWol'se$nternationalXs la#orator'. 3he castiron parts of these &uns have #eenpreserved: the si&htin& ar% and

the crutch whichsupported the trunnions.3he rench coat of ar%s,a shield with three eurs

de l's sur%ounted #' acrown decorated with aeurs de l's is on one ofthe &un chases and, atthe top of the chase,*ouis Y$$$Xs %ono ra%.



64/103

echanical vs.


65/103


66/103

So%e coins in &ood

condition, so%e al%ostentirel' %inerali/ed.

Still a possi#ilit' of&atherin& infor%ation

fro% various valle'sand pea5sin corrosion la'ers.


$%a&es courtes' of the Eille5e Eendrich.



67/103

p to 2? alu%iniu% car#onate rinses created a

attened #lac5 coin with %inor corrosion re%oval, #utno chance of seein& an' detail. echanical cleanin&would have #een #est.




68/103




69/103







70/103







71/103

$%a&e courtes' of the Aett' useu%.

iniature "ortrait

9ust of a Eo%an,Ro%an, 2? 9C - 2?. 9ron/e with&lass-paste inla's.

3he #ust is shown

#eforeconservation,illustratin& pustularcorrosion withpittin& created #'

#ron/e disease.




72/103

iniature "ortrait 9ustof a Eo%an, Ro%an, 2?9C - 2? . 9ron/ewith &lass-paste inla's.

3he #ust is shown after

conservation 3here is still a pro#le%

with patina sta#ilit'. re all patinas si%pl'

&olden fro% ori&inal

#ron/e or &reen fro%corrosion1


of Copperof Copper



73/103

echanical cleanin&





74/103


echanical cleanin&

"artial cleanin& of a #ron/e Aer%an to5en




75/103

echanical cleanin&of a to&&le pin.

3oo %uch1

of Copperof Copper




76/103


77/103

Shan& 'nast' din&,#ron/e, shown afterelectrol'tic strippin&.

$%a&e courtes' of Honolulu cade%' of the rts.

CopperCopper



78/103


Leel straps durin&

desalination fro%BM. avis shipwrec5.

9ron/e rudder pin fro%BRapid wrec5.




79/103


80/103


BRapid shipwrec5 coin

3reated for 4 wee5s in 2@ sodiu%ses=uicar#onate




81/103

9en/otria/ole (93) eposits &rowin& on Copper allo' o#0ect durin& 93

treat%ent.





82/103

Conservation of Copperpp




83/103

Conservation of Copperpp

3his Ro%an #ron/e inthe Aett' collectionshas a copper sulphidepatina, hence the dar5-#rown colour.

Hi&hl' unco%%on in#ron/es which are notfro% an anaero#icenviron%ent.

"ro#le%s with this 5ind

of patina: %i&ht theo#0ect even #e a fa5e1

Could recall the wor5 #'Schwei/er on B*andand *and patinas.




84/103

9ron/e horse trappin& inthe Aett' Collection.

7er' 6nel' developedepitaxial patina of cupritepreserves the shape of thesurface contours

excellentl'. 7er' li&ht cleanin& would

#e carried out, if that.

Could sta#ili/e with 93 or93 and 3 !@ in


85/103

3he controvers' stirred up#' the patina re%ovaltechni=ue of "hoe#e entEeil was useful in furtherdevelop%ents.

She used &lass-#eadair#rasive techni=ue, #utChase and 7elo/ showedthat so%e %etal could #ere%oved too in the

process of patina re%ovaland repatination followed#' "araloid 9J2 coatin&.

CopperCopper




86/103

How to treat suchstrea5in& 1

One old %ethod is toclean with a%%onia andchal5 or pu%ice. 3henoil the surface with

linseed oil, or tun& oil or#eeswax.

pppp




87/103

Shipwrec5 #ron/e 6nds$%a&e courtes' of 3he 7ictorious 8outh.

9od' parts of #ron/e statues

of various dates. ound inthe driatic Sea near 9rindisi

pppp



88/103

$%a&es courtes' of the 3oledo useu% of rt.

3he %a&ni6cent #ron/esfro% Riace fro% ?thC 9C.

ound in sea near Cala#ria in$onian sea. .

a' have #een #lac5patinated #ut this could #efro% sea #urial.

Conserved with eccentric9J %ethod usin& a%%oniain %ethanol followed #'h'dro&en peroxide in%ethanol and RH testin&, air-a#rasive cleanin&, RH

testin&, local treat%ent with

of Copperof Copper



89/103

3he 7ictorious 8outh

conservation. earl' all classical

lar&e #ron/es have#een found in the sea.

Statue was found indriatic Sea after stor%in +;Gs #' a6sher%an fro% ano. $twasnGt new whenori&inall' lost at sea.

*ar&e ones on land#ro5en up for recastin&or rewor5in& of the

#ron/e. $%a&e courtes' of the Aett' useu%.

pppp



90/103

Crude ori&inal cleanin& fro% +;Gs has

scratched the patina awa' revealin& #ron/e%etal.

Cast in four separate piecesand then 0oined %etallur&icall'.

pppp




91/103

3he #ron/e was cleaned #' hand and the loose left

ar% was re%oved. 3he cla' core was partiall're%oved. 3hen the #od' was i%%ersed in heatedsodiu% ses=uicar#onate.


pppp



92/103

3hen a vacuu% treat%ent was

used. 3hen distilled water was

applied, with periodic exposureto hi&h RH.

Ehen #ron/e was sta#ili/ed,the ar%s were reattached.

3wo stainless steel #ars wereinserted.

s'nthetic resin was used toattach the %odern ar%atureinside the nec5, shoulders,upper ar%s and ri&ht 5nee.

pppp




93/103

easures for wet %etallic o#0ects: #ron/e, #rass,

lead and silver can &enerall' #e allowed to dr'out. $ron %a' #e #etter stored in ox'&en-freeenviron%ent, can use ox'&en scaven&ers insealed 0ar or #ox, silica &el, or store in water withsulphite added to %op up ox'&en. Silica &el %a'not #e enou&h for heavil' corroded iron.

pp



94/103

$%a&e courtes' of www.culture.&ouv.fr>culture>archeos%

pp

rench Ro'al av'

ship fro% the 6rst halfof the Y7$$th Centur'li&htened the ship #'unloadin& artiller' andar%s.

o evidence was foundof a shipwrec5

+ swivel &uns wererecovered, J #ron/eand ; wrou&ht iron withiron-shod #arrels.

3hese were s%all, low-cali#er, #olt-head

swivel &uns.

ConservationConservationf Cf C


95/103

of Copperof Copper

$%a&e courtes' of

www.culture.&ouv.fr>culture>archeos%

3wo #ron/e swivel &uns have #eenrestored #' rchWol'se$nternationalXs la#orator'. 3he castiron parts of these &uns have #eenpreserved: the si&htin& ar% and

the crutch whichsupported the trunnions.3he rench coat of ar%s,a shield with three eurs

de l's sur%ounted #' acrown decorated with aeurs de l's is on one ofthe &un chases and, atthe top of the chase,

*ouis Y$$$Xs %ono ra%.



96/103

3he *ur is a 9ron/e &e %usical instru%ent.

*urs were usuall' %ade in s'%%etricalpairs, with identical tunin&.

3he *ur is 5nown fro% orwa', Sweden andnorth Aer%an' #ut %ost, !J, have #eenrecovered fro% anish #o&s. 3he earliest6nd is fro% the end of the +Nth centur'.

3he treat%ent these *urs have receivedshows clearl' how conservators have #eeninuenced #' chan&in& ethical standards.

$n earlier ti%es the %etal was cleaned inacid or heated Zso that the #ron/e ac=uiredits natural li&ht 'ellow colour.Z 9ul&es weres%oothed out and the sections of tu#e weresoldered to&ether, usin& copper tu#es. 3heidea was to %a5e the lurs pla'a#le, toinvesti&ate their pitch and ti%#re.

$%a&e courtes' of www.nat%us.d5>cons>x.



97/103

fra&%ent of a *ur fro% 'rup with enlar&e%ents of

an ancient repair (ri&ht) and a recent repair (#elow). 3his section was found in two pieces

in +;+ and sent to the ationaluseu% in en%ar5 in +;2. 9'

that ti%e the two pieces had #eensoldered to&ether. 3he %useu%re&ister records: Z... in the 9ron/e&e the tu#e had #een repaired witha .!? % wide plate,

that is still attached this patch %ustcover the 0oint#etween the lurXs

6rst two sections...Z . $%a&es courtes' of www.nat%us.d5>cons>x.



98/103

ore %odest conservation.

pair of lurs recovered in+;NN fro% a peat stac5 inlv5[r in 7ends'sselprovided an opportunit' to

investi&ate an un-conservedpair of instru%ents.

3he close up shows polishin&%ar5s fro% the ori&inal9ron/e &e surface.

Ee cannot #e sure thattraces found on the otherlurs discovered in the lastcentur' are ori&inal, or the

result of a restoration. $%a&es courtes' of www.nat%us.d5>cons>x.



99/103

Restoration and %ountin& of the lur

fro% lv5[r. 3he %outhpiece was found in

several pieces. n in&enious supportallows the instru%ent to #e hun& for

exhi#ition without usin& &lue orsolder.

$%a&es courtes' of www.nat%us.d5>cons>x.



100/103

9ron/e spearheads




101/103

nal'/in& an


102/103

nal'/in& a #ron/e #ust

fro% the Aett'.




103/103

Mane 9assett anal'/in& a

#ron/e fro% the Aett'.

Documents

Conservation of Copper