Mar
27
Cleaning Bronze Statues

Cleaning bronze statues is a preventive conservation treatment. This means that it is carried out primarily to slow the natural degradation of an object, in this case a bronze statue, in its particular environment. 

More than any other material used in sculpture, bronze requires cleaning because it is a reactive metal. It is the copper content, within the alloy, that enables the surface to corrode.

cleaning bronze statues

Corrosion doesn’t immediately look shocking or ugly. It begins, as so many things do, by being hardly noticeable at all – perhaps a slight freckling of the surface or run mark, but over time if the statue isn’t cleaned then you will see the surface change in a permanent way. 

The term cleaning is a general one and that can be misleading. There are different ways of cleaning that should all be part of the long term care of a bronze sculpture.

  1. Spot Cleaning is a valuable technique. Bronze statues located inside will need dust removing. Externally, this is more likely to be guano, detritus from trees and insect debris. The technique should be carried out predominantly dry with minimal wet or solvent cleaning. 
  2. A maintenance clean is more thorough, but usually carried out by hand. This involves the removal of all dirt, grease and grime usually using soap solution and a small amount of solvents, followed by the through application of a protective coating.  This mode of cleaning is slower but absolutely essential for the long term care of a bronze sculpture.cleaning bronze statues
  3. The full removal of a coating can also be termed cleaning but does not happen during maintenance cleaning. This often happens during restoration work when a protective coating has failed or a coating has been added, at some point in the statue’s history, to disguise the true condition of a bronze sculpture’s surface.  Methods such as super-heated water or solvent cleaning are used in this mode of cleaning. 
  4. Deep cleaning is carried out when a statue has been left for such a long duration that hand cleaning is no longer viable. Deep cleaning involves super-heated water and removes all guano and dirt residues. This mode of cleaning will strip any existing wax-based protective coatings away, but that is rarely a concern because statues left for years rarely have any protective coating left.                                                                           cleaning bronze statues

Cleaning bronze statues does not mean removing the patina on a statue’s surface. Contrary to what some say on YouTube, it never involves polishing them up so that they are gleaming (with some brasso and elbow grease). It should be about preserving the bronze’s surface, not removing it. 

Cleaning bronze statues should never involve applying acids or alkalis to the surface of a bronze – even if it is natural (no lemons or vinegar!) 

Keeping a bronze statue clean is not just about aesthetics, regularly removing grime, guano and other substances, lowers the rate of breakdown of the bronze’s protective coating.  That means that cleaning bronze statues regularly helps to keep the protection viable for longer. Spot cleaning is essential for removing large particulate matter, maintenance cleaning removes grime and residues that may not be obvious to the naked eye and consolidating the existing protective coating. This combination of cleaning techniques is good for the statue and for a client’s budget because the more robust the coating is, the more stable the bronze will be and that should always be the aim of cleaning bronze statues. 

Apr
28
The Vandalism of the Bomber Command War Memorial
Bomber Command Monument Cleaning

Cleaning of this iconic War Memorial and restoration was necessary after white gloss paint was thrown over The Bomber Command War Memorial in Green Park earlier this year.

Conservation work by Antique Bronze took place some weeks later after the memorial was initially hit.

The monument is a magnificent creation by sculptor, Philip Jackson, who won the Marsh Award in Public Sculpture for his work. It’s easy to see why: the artist has personified bravery, comradeship and patriotism in the stance of his figures, their detail and expressions. We enjoyed many conversations with the public who came to visit the memorial during our works.

Why This War Memorial Is Special

Several of the visitors had interesting facts to tell us about the Bomber Command unit which was instrumental in winning World War II.  Of the 125k men who served, half lost their lives. Bomber command crews came from 60 different countries. Every member was a volunteer.  The average age of those killed was 23 years old.

Hours after the monument was vandalised, an emergency clean was undertaken. It was then that the RAF Benevolent Fund was advised that  a monument cleaning service specialising in conservation should take on the  due to complexities of working on bronze.

Removing the remnants of white paint from the bronze’s surface was not an easy task. Although much of the paint had been taken off in the initial clean, thousands of smaller splashes remained.

vandalism of war memorial

Monument cleaning often involves dealing with vandalism.

The surface of the sculpture had originally been hot patinated, but areas were fragile. Before the treatment was started, we noted that there was evidence of localised loss of original patina. This meant that to avoid further loss of the surface,  the cleaning technique decided upon had to be very gentle indeed.

vandalism on Bomber Command War Memorial

An area of loss of original patina

The aim of bronze conservation is always to leave as much of the original patina intact as possible. 

Another difficulty was that the surface was highly detailed meaning that many of the tiny splashes were located deep inside small grooves making them hard to excavate.

It may seem like superheated water or high-pressure cleaning may be an obvious option for this type of vandalism, but the fragility of the patina made this route a concern. The paint was so firmly adhered to the textured surface that to shift it, force would have to be centred on a very tiny surface area which had the potential to break-up more of the original patina.

Solvent cleaning was useful for softening the deposits, and soft nylon brushes did clean the surface without damaging the patina, but this cautious route on such a large monument made it a slow task. Our most useful tool came in an unexpected form – small wooden coffee stirrers provided the perfect profile to clean out grooves, but was soft enough not to scratch the patina.

War Memorial Cleaning Tips for Custodians Paint residues spread across the bronze at Bomber Command

 

 

 

 

 

 

If your memorial has been vandalised, consider these three tips:

  1. Never use sticky tape to cover the surface – even if the graffiti is offensive. Industrial tapes contain residues in their adhesive which will etch through a bronze’s patina often causing more damage than the paint layer itself.
  2. Call a professional monument cleaning service (like us!) for advice and help – if you try to use high-pressure cleaning methods on bronze, and you have a vulnerable surface, you can instigate serious loss of the original finish.
  3. Don’t ignore vandalised bronze – it invites further anti-social behaviour.
Feb
12
How To Care For Bronze Statues in Your Home

Caring for bronze sculpture in your home is much easier than those in your garden. Indoor bronzes have an easy time of it compared to their large companions outdoors. They are sheltered from the urban air and ever-changing weather, but their environment still has an impact on them and if you want to keep your small bronzes as stable as possible then consider these ten tips.

1: Dust Regularly – Don’t be frightened to touch a bronze just because it’s an artwork. If you use a dry micro-fibre cloth or a soft brush, you’ll be doing a lot of good rather than harm. Caring for bronze involves removing dirt and grime. This prevents reactions between the pollutants in dust and the metal’s surface. We all hate more housework, but preventing corrosion is always better than curing it.

2: At least once a year, give the statue a thorough clean. Use white spirit to remove dirt and grime – I use a cotton rag to apply it. Then put a protective coating in place – this is one of the best ways of protecting a bronze’s surface. Outdoor pollutants from traffic do infiltrate buildings. Over time, they will corrode your bronzes (Grontoft et al, 2016). Rub on microcrystalline wax and burnish with a bristle brush or cotton rag as you might your shoes. It will improve the bronze’s lustre and retard surface change.

3: Internal materials like wooden floorboards and furniture emit acidic gases such as acetic or formic acid. These will damage your bronzes particularly if airflow is static and if the temperature of a room is likely to fluctuate widely. To care for your bronze sculpture, consider where you locate your small bronzes. Try not to display them in sealed cabinets made from materials containing hard and soft woods or plywood (Gibson, 2010)

Care For Bronze Statues by Not Touching Them

4: Avoid handling your bronzes. If possible, lift your bronzes with a clean cloth rather than touch them directly. Sweat from the hands is acidic and will corrode metal. Wax is only a thin barrier layer.

5: If you are storing a small bronze rather than displaying it. Ensure that the packaging materials are suitable. Do not wrap bronzes directly in bubble wrap or plastic. Houses tend to have poor humidity controls and though it might surprise you – bronzes do hold water. When they heat up that water will evaporate and if you’ve trapped it in plastic – you’ll get corrosion activity beneath the plastic.

6: If you accidentally spill red wine, tea, coke or even water on your bronze – then run for a cloth! Just because it’s not a textile that stains – don’t assume that the liquid won’t do any harm. If you whip it off quickly, then harm is averted. If you leave it to dry out, the metal is likely to etch in the perfect shape of the splash or spill. A little warm water on a clean cloth as dry as possible will enable you to remove the liquid and save your bronze surface. Don’t forget to dry your bronze after you’ve washed it though – that’s very important. 

7: Admire your bronze often – don’t ignore it. If you keep an eye on your sculpture,  you will notice if there is any change occurring. If rapid change occurs within a short period, then the chances are it is being exposed to something. Be mindful, and you could prevent a bigger conservation problem. 

care of bronze statues

The owner of this bronze noticed the surface was pitting

8: Think about where you locate your bronze. If a statue is in a busy area of the house, it might get knocked, and scuffed. Bronze looks tough, but often small bronzes have delicate sculptural detail, and one bang can see sections break off or snap. Dents are very hard to remove successfully. Drafts also carry outdoor pollutants inside and humidity will peak and trough more which won’t do your bronzes any good.

9: If you want to give your bronze the Rolls Royce treatment then a high-spec display case made with materials that do not emit gases will go a long way. Though undoubtedly an expense, it has been shown that cases with robust seals prevent traffic pollution getting in, provides extra security if you are burgled, prevents household damage like spills and knocks. A low and stable relative humidity under 40% is ideal. It’s also wise to add some activated carbon to the base of the case to absorb any stray pollutants.

10: If you notice a greenish, powdery deposit on your bronze which is easily brushed away, but returns quickly – get it to a conservator ASAP! This deposit is a sign of active corrosion and needs quick, skilled treatment to prevent metal loss.

If you would like help or advice on caring for your bronze statues, do give Antique Bronze Ltd a call on 0208 340 0931 or take a look at our small bronze restoration page

References:

Terje Grontoft, David Thickett, Paul Lankester, Stephen Hackney, Joyce H. Townsend, Kristin Ramsholt & Monica Garrido. “Assessment of Indoor Air Quality and the Risk of Damage to Cultural Heritage Objects using MEMORI dosimetry” Studies in Conservation 61:sup 1, 70-82. Routledge & IIC 2016 Link Here

Gibson, L.T. (2010) Acetic and formic acids emitted from wood samples and their effect on selected materials in museum environments. Corrosion Science, 52 (1). pp. 172-178. ISSN 0010-938X

Feb
19
How to Clean a Bronze Sculpture

How To Clean a Bronze Sculpture




Recently, we had an enquiry from the archivist at Pembroke College, Oxford – Amanda Ingram about how to clean a bronze sculpture.

The college had rather a splendid bronze bust which had, unfortunately, been languishing in a basement for some time. It was to be relocated to a prominent position in the college, but it had to be cleaned. Amanda came to us for advice.

She said,

I have given it a light wipe with distilled water to remove surface dust but there is quite a lot of it which has a kind of fine crust on the surface. It is as if someone has wiped it with a dirty rag (for example containing paint residue) and this has set on the surface. The other thing is that it looks like parcel tape or something has, at some point, been stuck on his face and has, likewise, left a hard adhesive residue.

Our Advice

Our first suggestion was to try a solvent like acetone to remove the parcel tape residue and this worked extremely effectively. The rest that follows relates only to the dirt. Regarding the wiped, crusty areas we recommended trying to clean with some soap and water. If it worked, then to apply a couple of coats of micro-crystalline wax to the surface for protection. We suggested trying a small patch first and look at the outcome before going too far.

Amanda asked

“Is nail varnish remover a suitable acetone or does it need to be a purer version? And, what sort of soap is best to use?”

Our advice was to buy a pure acetone as nail varnish remover often has added components. Although neutral soap solution is always a safe bet, when cleaning a bronze sculpture; it can be ineffective at cleaning stubborn dirt. This means more rubbing of the bronze’s surface is necessary which isn’t a good idea. Diluted Vulpex soap is slightly alkaline, but providing it is properly removed, can be a gentler method.

Amanda returned a short while later reporting that unfortunately, the dirt was still stubbornly in place.

Our advice was to try a little abrasion with something very fine. Just to do a very small area at the start with something like a very fine bronze wool and that this could be used with a little soap solution.

Amanda’s results speak for themselves. She applied Renaissance Micro-Crystalline wax after for the statue’s protection. Her careful approach has yielded some great results. Well done, Amanda!

If you’d like to know more about how to look after bronze sculptures, sign-up for our online course, going live in 2019 

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