Church Brasswork
Will Murray
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Detail of a chancel screen at Bristol Cathedral: the delicate filigree work is vulnerable to mechanical damage, while the handle of the latch is more exposed to chemical residues from bare fingers, and the fine details trap residue from polish (Photo: Jonathan Taylor) |
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Brass is an alloy of copper and
zinc that has always been favoured
for its beauty and workability. In
ecclesiastical circles it has a long history of
use in fixtures and fittings such as lamps,
chandeliers, gates, rails and door furniture,
as well as more movable objects such as
crucifixes, lecterns, candelabra, jugs, plates
and cups. Musical instruments, especially
hand-bells and cymbals, also come to
mind, and of course brass can be used in
the manufacture of organs and organ pipes.
The Romans made great use of brass,
for instance in their coinage and armour,
and while it has been suggested that the
Jews rejected it precisely because of its
associations with the Roman occupiers of
Palestine, it is likely the Christian church
would have made use of brass from its
earliest days. In medieval times brass
continued to be used although its quality
became much more variable. In the
modern age the increased understanding
of metallurgy and improved methods of
manufacture brought brass objects within
the reach of any parish, with designs
shaped by a variety of influences from the
gothic revival to modernism.
This article looks at some of the
care and conservation issues that can
arise when looking after brass objects.
It excludes the care of monumental
brasses as these tend to have their
own special problems, often due to
their location in floors where they are
vulnerable to accidental damage and
the heavy use that can arise if they
are popular for making rubbings (see
‘Monumental Brasses’ by William Lack).
What makes brass so popular for the
manufacture of so many items associated
with churches and religious practice? As
an alloy of copper with zinc, the metal
has a range of colours depending on the
zinc content. The high-zinc brasses may
have up to 40 per cent zinc and are usually
a silvery yellow colour, while a low-zinc
brass with only 5 per cent zinc might tend
towards a pinkish copper colour. The
mid-range brasses, which are the most
common, typically contain 25-35 per
cent zinc and have a warm golden yellow
colour. Thus brass exhibits something of the beauty and value of gold with the
durability, workability and lower cost of a
copper-based alloy. However, unlike gold,
it is not inert and it will oxidise slowly if
not protected by wax or lacquer.
Sheet brass is made by hot-rolling
and cold-rolling cakes of alloy until the
desired thickness and size is achieved.
The forging and rolling of brass causes
work-hardening and embrittlement so
the metal has to be annealed in between
working – that is, heated to a temperature
that allows the metal crystals to rearrange
themselves, with the reduction of internal
stresses leading to a softening of the
brass. Repairs to badly damaged sheet
brass artefacts may also require annealing
before the metal can be reshaped.
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An eagle lectern in St Mary Redcliffe, Bristol dated 1638 (left) and a detail (right) of the base of a late 19th-century eagle lectern in Bristol Cathedral: the ornate scroll-work is of copper, which is particularly vulnerable to accidental damage. (Photos: Jonathan Taylor)
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Brass for casting can contain some
lead as this reduces the melting point and
makes it easier to pour when molten. Lead
has also been added to brass to make it
easier to machine, for example for making
plumbing fittings with screw threads. In
recent years concerns have been raised
about the lead content of brass used for a
variety of items, including pipe fittings, due
to the leaching of lead into drinking water,
and even brass keys due to the potential
transfer of lead out of the metal and onto
skin during handling.
Today the amount
of lead allowed in brass for such uses has
been strictly limited in some countries.
However, the author is not aware of
concerns about the lead in items of church
brasswork, presumably because no health
problems have been reported or detected.
Brass is relatively resistant to tarnish,
yet is malleable and easy to work in sheet
form or cast into a mould to make heavier
pieces, and components are easily joined
together by brazing, soldering or riveting.
It also takes well to polishing where the
use of increasingly fine abrasives leads
to the production of a smooth bright
surface. This contrasts with copper and
bronze which have less useful working
characteristics, and which tend to tarnish rapidly if cleaned and polished.
Indeed, bronze and copper are normally
deliberately patinated as otherwise the
task of maintaining a bright and attractive
surface would be endless. But brass can be
maintained in a bright state with relatively
little effort if the general conditions in
which it is kept meet reasonable standards.
Coatings should be mentioned as
they can present significant issues. Brass
can be gilded either by oil-gilding (when
gold leaf is applied to the surface with
an adhesive), by mercury-gilding, or by
electroplating. The layers of gold applied
are very thin and can easily be removed by
inappropriate treatment. Brass may also
be protected by a durable lacquer which
will prevent tarnishing, but if the lacquer
is damaged, the exposed area of metal
will tarnish, creating visibly darker areas.
The most problematic items are those
that once had a coat of lacquer which
has been partially removed by cleaning
and polishing efforts, leaving a sort of patchwork quilt of lacquered brass which
remains bright, and unprotected brass
which tarnishes comparatively quickly.
What can harm church brasswork?
The agents of deterioration include high
humidity, which can increase tarnish
and corrosion rates, and salts, which
can be naturally present in coastal
areas but can also come out of walls
and floors if there is a lot of moisture
movement through the building fabric,
and which also encourage corrosion if
they come into contact with metal.
Handling brass with the bare hands transfers oils, salts and acids to the metal
surface and these can interact with the
brass over time to cause finger-marking,
tarnishing and corrosion. Of course,
many of those who attend church cannot
be asked to wear gloves simply to keep
the brassware bright, but the staff and
volunteers who care for church furnishings
can certainly aid matters if they wear
gloves when handling bright metals.
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Detail of a fine processional cross from St Margaret’s Episcopal Church, Aberdeen, before consolidation and repair: dated 1878, it is a composition of earlier pieces, including a brass crucifix believed to be 15th or 16th century and mother of pearl carvings depicting the evangelists. (Photo: Will Murray) |
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Cotton gloves are good for the job, but
can be slippery, so some come with special
rubber dots on the surface to increase
grip. Household rubber gloves are useful
as they are hard-wearing, but they are not
very sensitive. Disposable latex gloves are
useful but can become uncomfortable if
worn for long periods, and some people
are allergic to latex. Disposable nitrile
gloves such as those used in the medical
professions (Kimberley-Clark purple nitrile
exam gloves for example) are very useful
for collection care work as they combine
comfort with protection of both the skin
and the objects being handled.
Candle wax is rather acidic and will
react with the copper in brass to produce
green corrosion products, so should not
be left in contact for long periods of time.
Other acidic materials such as wine and
foodstuffs can also attack brass, causing
pitting and corrosion if left in contact
with the surface.
Soiling is a problem, as dust and dirt
are abrasive, and contain materials which
encourage tarnishing and corrosion, or
when in contact with metals act as sites
where corrosion problems can start. If
candles are used in the buildings, the soot
they produce can slowly build up and
soil surfaces, but this is perhaps less of a
problem than it once was.
Inappropriate cleaning materials can
harm brass by cleaning too aggressively,
removing a thin layer of metal each time
the object is cleaned; this can eventually
cause the loss of surface detail, especially
on decorated pieces. Cleaning and
polishing materials can also leave residues
on the surface and in recesses, often in
the form of white deposits of abrasive
powders that have not been properly
removed. Finally, accidental damage such
as scratching, denting or breakage is
always a risk, especially when objects are
handled or moved.
CARE OF BRASS
When caring for brass artefacts, the best
place to start is an assessment of the
object’s condition from a conservation
perspective. Each artefact is different, with
variations in design and manufacture, in
decorative surface detail and in current
finish or patina, as well as in the way it is
used in the church or elsewhere. These
variations all contribute to decisions about
what care methods to use.
For example, a pair of candlesticks
might be small and have a bright finish
showing signs of past polishing; in such
cases light cleaning might be best. An item
might be very large and anyone deciding
to embark on a mission to clean and polish
it top to bottom might be looking at a full
day’s work or even more; is there time
available to do a good job? An item might
show signs of gilding or lacquering or
another surface finish which means that
simply applying a metal polish might cause
damage or be ineffective; further advice
and discussion might be needed. An item
might show patchy tarnish and finger-marking
which will benefit from the careful
application of the right sort of polish. Or a brass item might show a deeply coloured
and even coat of tarnish which is
aesthetically pleasing in its own right.
Such patinas can become part of the
long-term appearance of the artefact and
thoughtlessly assuming that ‘all brasswork
must be bright’ can lead to the loss of an
appearance treasured by others. A non-brass
related example would perhaps
be the cleaning of the Sistine Chapel
frescoes which led to many complaints
that they had been over-cleaned and that
deliberately-applied materials had been
lost along with the soiling.
If your brass is already bright and
clean, the best way to manage it is by
timely maintenance with light methods of
cleaning such as dusting and buffing with
a soft cloth. Keep items clean and free
of dust and dirt as far as possible; don’t
leave food and drink residues on brass
plates and cups. Often a wipe over with
a damp cloth is sufficient to clean items.
Flatware such as plates can be immersed
in water with a little washing-up liquid
for cleaning, but items with more of a
three-dimensional shape may contain
voids or even structural elements such as
iron rods holding the parts together and
immersion is best avoided as any water
that gets trapped can cause corrosion. In
such cases, wiping with a cloth moistened
in warm water with a drop or two of
washing-up liquid is probably best.
Brass artefacts known to have
lacquered surfaces can also be gently
cleaned with a damp cloth.
Wax can be a problem on candlesticks
and other surfaces, and trying to remove
it using tools can cause severe damage
to the brass below. There are many
recipes for removing wax with both
freezing and application of hot water
being popular options. It is usually best
to use a hairdryer or a hot air blower
set to the temperature that will melt the
wax without overheating the object. As
the wax melts, it can be wiped up with a
paper towel and disposed of. Any waxy
residues can often be removed with a
towel moistened with a little white spirit,
a solvent which should be safe on all metal
surfaces. Follow safety advice and wear appropriate protective equipment when
using solvents such as white spirit.
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A war memorial from Minard, Argyll (above) part way through cleaning showing patchy tarnishing in the uncleaned areas which make the roll of honour difficult to read, and (below) a detail of a plaque with bimetallic corrosion around a fixing (Both photos: Will Murray) |
Handling brass with bare hands, as
has been mentioned, leaves oils and salts
on the surface which cause tarnishing,
so surfaces frequently touched such
as a chancel rail will benefit from
light burnishing with a soft cloth on a
regular basis.
If this proves ineffective in
preventing tarnish, the use of a microfibre
cloth designed for polishing metals such
as brass may be helpful. If necessary,
consider using a special brass polishing
cloth that has been impregnated with
mild abrasives and cleaners.
If the brass item has a thin patchy
coat of tarnish, then the use of cloths may
not be effective, and in such cases brass
polishes should be considered. These
come in a great variety, from the gentle to
the strong, and it is really a case of horses
for courses when it comes to choosing a
polish.
Some conservators tend to avoid
those brass polishes that leave a powdery
residue in recesses, as these can be difficult
to remove once they have dried out, and
sometimes the rather coarse abrasive
can remove more metal than might be
desired, but classic products like Brasso
polish are still in use in many places.
More gentle options include Duraglit
brass polishing wadding and Brasso brass
polishing wadding, which are based on
petroleum spirit rather than water and
thus must only be used while wearing
gloves. These waddings tend to turn black
when polishing the brass, but careful
burnishing after polishing should bring
up a bright surface and remove any visible
dark residues.
The National Trust’s Manual of
Housekeeping encourages staff and
volunteers who need to polish brass to use
Solvol Autosol, a metal polish designed for
use on a wide range of metals. It is a fairly
strong and effective cleaning and polishing
agent so should be used with care. It can
certainly be useful when more gentle brass
polishes such as the wadding polishes have
failed to make an impact. It too turns black
as it is used, and if fully burnished out it
should not leave any visible residues.
Many commercial polishes contain
a mixture of abrasives, chemicals and
waxes. The ingredients of any commercial
product can often be discovered by
searching online for the product name
and the MSDS, or Material Safety Data
Sheet, which will provide information
about ingredients and the health and safety
issues involved in the use of the product.
The waxes that are included in polishes
are designed to remain on the surface
and provide a protective layer against
future tarnishing. This is, in principle, a
good idea but the wax layer tends to trap
abrasives, chemicals, metal fragments
and anything else that was on the surface
during polishing. Some conservators
remove the wax and other polish residues
by wiping down the surface with a paper
towel or soft cloth moistened slightly with
white spirit. Once all the black residues
have come away, the surface may be
considered to be reasonably clean.
Of course having the wax present is
a good idea, as some protection against
future tarnishing is certainly helpful. Some
institutions go so far as to have protective
lacquers applied to their freshly-polished
brass, and this can give many years of
protection to those items that do not
see hard use. However, if the lacquer is
damaged, it can lead to rapid tarnishing
in the areas where metal is exposed,
and then there are decisions to be made
about removal and/or replacement,
which may require special facilities.
A better answer is a conservation-grade
wax polish such as Renaissance
Wax. Widely used by conservators, this
wax forms a clear self-healing coating
on bright metals. It protects to a great
extent against dust and humidity as well
as handling and tarnish. It can easily
be revived by the application of more
Renaissance Wax once a year, or as
required. It is easily removed with a soft
cloth moistened with a little white spirit.
If polishing the brass, the wax does not
resist the polishing process, and does not
have to be specially removed beforehand.
The only situation where Renaissance
Wax might not be useful is where there is
a great deal of complex decoration and it
would prove difficult to buff the wax up
to a good shine, or on uneven and porous
materials such as unvarnished wood
where again the wax will be difficult to
buff to a transparent coating.
Finally, when it comes to badly damaged
brass artefacts, repair is best left
to expert metalworkers. Such conservation
work might include annealing and
reshaping the metal, or joining broken
parts using the correct brazing techniques
or perhaps the use of cold-setting resins
such as epoxy resin. The use of soft lead
solder is often seen on brasswork that has
been repaired by amateurs wishing to be
of assistance, but the results leave much to
be desired as dull grey lead has no place on
bright yellow brass.
A list of accredited decorative
metalwork conservators can be found
at the Conservation Register.
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Historic Churches, 2015
Author
WILL MURRAY is an accredited conservator
and a partner in The Scottish Conservation
Studio LLP, a private-sector conservation
provider based at Hopetoun House near
Edinburgh. The studio specialises in the
conservation of paper and photographs,
costume and textiles, and artefacts and objects.
Its conservators also provide preventive
conservation advice, collection surveys and
training for museum staff and volunteers.
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