Inside the Museum of London

Following on from Jill Saunders’ recent blog, The main event, the closing post in the series on the conservation of the iron coffin from St Bride’s looks at fixing the final problem of supporting the coffin base. Come and see the coffin for yourself in our Doctors, Dissection and Resurrection Men exhibition opening on 19 October.

Figs. 1 & 2 An example of where the base is detached from the walls of the coffin.

Figs. 1 & 2 An example of where the base is detached from the walls of the coffin.

Our work on the coffin was nearly complete and we had stabilised a great deal of valuable material and discovered many things along the way. However, the object presented one final major problem to us in the heavy bottom sheet of the main coffin, which was only partly attached to the walls. This meant that whenever the object was lifted, the weight of this base was unsupported and pulled heavily on the attached regions. We felt this could eventually lead to the whole base falling out – which we obviously wanted to prevent. There were two main courses of actions to limit the risk of this undesirable occurrence; either we could find some way to adhere the base along the edges from which it had become detached (the suggested material was EPOPAST), or we could provide a simple base which the object would sit in (though not be permanently attached to) and upon which it could always be lifted. As is usually the case in conservation, there were interesting and worthy arguments for and against both treatment courses:

1. Adhering the base to the walls

Pros

• Could secure the base indefinitely
• Could be reversible if a release coating was applied first
• Would make the object as robust as possible in preparation for its future life of manoeuvring outside of museum conditions.

Cons

• Quite an interventive procedure, which could have issues with reversibility
• Practitioner inexperience in the proposed material raised competency issues. Limited time to complete treatment exasperated this issue
• If quite a large amount of fill/adhesion material was needed it could cause aesthetic disturbance.

2. Providing a carrying base (unattached)

Pros

• Would uphold the popular professional concept of ‘minimum intervention’
• Would support the base adequately if used properly
• Would prevent contact handling of the object.

Cons

• Could easily be separated from the object in the future or misused
• May interfere with future display requirements if secured and if unsecured the base would then be unsupported
• If secured, could cause damage where attached
• Would require further input from the technicians who we would depend upon to make it.

Unable to reach a decision, we decided that the best thing to do was to practice using the proposed material to test its manageability and properties (e.g. strength, adhesion, working time) and our ability to use it. The quantity needed would be key to our decision. We found some scrap modern iron which would provide a good test as its surface would be harder for the material to adhere to than our object. If it managed this we would be confident it could work. We had the iron cut into four pieces by our technicians so that we could test joining lacquered and un-lacquered pieces to test the release properties of the coating we had used i.e. if it had a detrimental effect on adhesion or if we would need to add more to ensure reversibility. We had to ‘double glove’ when mixing the two components of the material because of all the glass fibres it contains. The material comes in two components, one a putty and one more liquid which have to be mixed according to a specific ratio measured by weight. The hardening depends upon a reaction between the two components.

• We arranged two sets of iron sheets at c. 90° to one another with a gap in between in order to mimic the base and wall:

Fig. 3 The ‘wall’ pieces are clamped in position. The surfaces of the set on the left are unprepared and those of the right set are lacquered

• After the two components of the material had been thoroughly mixed we filled the gaps and spread out a small amount on each ‘base’ piece to provide additional test information about adherence to the untreated and lacquered surfaces:

Fig. 4 The test sets are filled with Epopast

• We were pleasantly surprised to witness the strength of the material in the morning which had both good adhesion to the surface and easily carried the weight of the attached piece. We also felt that we could use even less than we had in our experiment to secure the base, limiting the aesthetic disturbance.

Fig. 5 & 6 The Epopast has cured (hardened) and formed an effective join between the two pieces

Fig. 5 & 6 The Epopast has cured (hardened) and formed an effective join between the two pieces

We proceeded to mix up a fresh batch to use on the object, this time adding powder pigment to help the material blend in (the green colour is the natural appearance of the product). As the base and walls had now been lacquered three times we did not need to add an additional release layer. We filled along the gaps and when the material had hardened we used a stiff brush to remove any glass fibres which were sticking out. We lacquered the filled areas to seal in any remaining loose fibres and reduce aesthetic contrasted with the object but decided not to blend them in any further (using paints) as it is commonly considered mote ethical in conservation not to completely hide new material.

Fig. 7 The EPOPAST in place, filling the gap between the coffin base and walls.

Following on from our recent blog post Coffin decoration & Mrs Campbell, Jill Saunders tells us more about the conservation work on the iron coffin from St Bride’s, focusing on the lacquering and consolidation of the main coffin.

Dust removal, corrosion and encrusted debris reduction and lacquering of the lid now complete, we set our sights on the more complex coffin base, which we had cleared of debris but were yet to clean. As explained in previously blog entries, this object had fragile decorative remains on outside walls as well as intricate interior extant components:

Fig. 1 An area of the preserved decoration featured on the exterior walls of the coffin, shown here at the head end.

Fig. 2 The surviving interior material remains at the foot.

Fig. 3 The surviving interior material remains at the head.

A key concern was the preservation of the external decoration (Fig.1).  As it was so fragile and vulnerable to loss, we decided that this is where we should first direct our attention. The lacquering had worked well to secure and accentuate features on the lid. But before we could add this coating material we wanted to reduce the dust, bulbous corrosion products and debris on the external surface. Though the removal of material from an object can always be viewed controversially, we felt this level of cleaning was justified to protect the integrity of the material remains and help to communicate its features to the viewing public.  Again we used a brush and object vacuum, with netting over the funnel in case of loss, and a stiff brush and Garryflex, being careful not to disturb the features, before applying the same conservation grade acrylic resin which we had used to lacquer the lid.

Fig. 4 An area of the external main coffin before coating.

Fig. 5 The same area after coating.

During this process we discovered areas of a dull, pale silver metal; the same in appearance as we had found in places on the lid (Figs. 6 & 7). This metal was a thin sheet directly on top of the iron and beneath the remains of decorative elements. We knew that wooden caskets of the time often had lead sheeting and so we conducted a chemical spot test to support this theory, which gave a positive result (Fig. 8). As previously stated in the Coffin decoration & Mrs Campbell blog post, chemical spot tests are indicative only and materials science analysis such as SEM or XRF would be needed to certify elemental information. However, the historical context and properties of available metals also strongly indicated the use of lead for this type of sheeting.

Figs. 6 & 7 Areas where lead is clearly visible on top of the iron and beneath decorative elements.

Figs. 6 & 7 Areas where lead is clearly visible on top of the iron and beneath decorative elements.

Fig. 8 Jon conducts a chemical spot test on a small sample taken from one of these areas.

After lacquering the outside we turned to the inside which, like the lid had quite a lot of dust and bulbous crusty corrosion products which we wanted to remove (Fig. 9). We covered internal features at the base and the head as well as a few fabric patches attached to the walls to protect them before following the same methodology of brushing and vacuuming, using a scalpel occasionally to reduce stubborn corrosive mounds protruding from the surface. The inside walls were now ready to be lacquered but we felt that this process could wait and wanted instead to deal with the loose and friable interior features at the head and base. Very light brushing and vacuuming provided final dust reduction, but the material was so loose we soon reached a point where we had to accept some minimal dust remains so as not to cause unacceptable material loss and damage. We decided to consolidate these regions to keep them intact and secure and we had plenty of samples of the uncontaminated materials if needed for future analysis. We used a conservation grade polyvinyl resin and applied it with pipettes so that no potentially destructive contact with the material was necessary. For example, as would have been caused by brush application.

Fig. 9 The interior walls were thick with dust and debris caught in protruding corrosion.

Fig. 10 The internal organic remains at the foot end during consolidation.

Fig. 11 An area of coated interior wall.

(N.B. most of the shine is because it is freshly applied and still wet).

Once these areas had been secured we progressed to lacquering the interior walls and the base. The majority of the object was now complete but we still needed to address the issue of the base, which in places was detached from the walls of the coffin and needed structural support.

Watch this space for the next entry covering work conducted to support the coffin base: Bottom heavy hazard.

Following on from our recent blog post, Turning over a new lid, Jill Saunders’ latest entry reveals how scanning electron microscopy analysis helped identify the different materials, both on and inside the iron coffin from St Bride’s. Read on to find out more…

In blogs to date you may have noticed that I have often said ‘suspected leather’ regarding exterior decorative features, and have merely suggested possible identifications for material from the coffin interior such as sawdust, woodchip, straw or hay. Our socio-historical research into burial methods and coffin manufacture, together with macroscopic (with the naked eye) and low-magnification visual examinations, have allowed us to make educated guesses. However it is crucial not to take these conjectures for granted unless you can observe definitive attributes, which are often only clear under very high magnifications such as scales on hair fibres. In terms of conservation, incorrect assumptions could lead you to misunderstand all sorts of information about structure and likely condition, which obviously would hinder your ability to tailor the best possible conservation approach to the material at hand eg electing a suitable consolidant. Further, incorrect identifications could lead to misguided historical conclusions, whereas correct knowledge about materials present would be valuable information.

Fig. 1 A summary of samples taken with accompanying images

Fig. 1a Interior: Coarse textile

Fig. 1b Interior: long fibrous material, suspected straw/hay

Fig. 1c Interior: Suspected woodchip/sawdust

Fig. 1d Exterior: suspected leather exterior facing

Fig. 1e Exterior: Suspected leather border decoration

We decided to take samples from key materials (Fig. 1) and examine them with images generated through SEM (scanning electron microscopy) analysis. The organic samples were gold coated to generate clear images more easily. The tiny losses needed for a sample from an object of this size would be negligible and well worth it for the sake of generating data, which could lead to positive identifications. Additionally the coated samples on their staves have all been saved and filed, ready and available for future analysis so that theoretically more need never be taken.

Fig. 2 The mounted samples from the coffin

Fig. 3 Gold plated ready for SEM analysis

Fig. 4 The sample in the chamber at UCL

Summary: Coarse textile
The images reveal the same simple weave visible to the naked eye:

The fabric seems to be composed of two different fibres. One is animal hair, probably wool, with characteristic scales, and appears one is plant material:

They seem very much interwoven, like a coarse matting material made from fibre scraps:

Conclusions:
The material appears to be a cheaply made type of coarse matting. The presence of animal hair/wool was surprising as this could not be discerned with the naked eye and, though we knew the material was organic, we had thought it would be entirely plant based.

Summary: Suspected hay/straw
Under high magnification, the material, which had the appearance of thick hair to the naked eye, looks like rough wood chips of different types of wood.

The sample contained scraps of other material, as of yet unidentified.

This scrap on the left seems to show straw-like material matted together. The piece on the right is unidentified to date and may be from original material or be contamination.

Conclusions:
The sample appears to be a plant based coarse packing material, but more research is needed to identify some of the images captured.

Summary: Suspected leather
We took two samples in order to image the upper side and underside of the suspected leather:

Both showed protruding fibres:

Summary: Suspected leather (border)
Appears to be same material as above:

Conclusions:
The protruding fibres are characteristic of leather.

Watch this space for the next entry covering the application of lacquer to the coffin lid: Lacquering the lid.

After our recent Initial Investigations blog post, Jill Saunders tells us more about the conservation work on the iron coffin from St Bride’s, this time focusing on the coffin lid.

Fig. 1 The coffin lid as it was displayed at St Bride’s (underside visible)

The lid of the coffin had key features relating to the object’s anti-theft function with iron pegs all the way around which would spring and catch under a ledge on the coffin base, keeping the casket locked tight. Though the main pegs were quite robust, the catches were more vulnerable and we had to be mindful of them during treatment and any manoeuvring. In addition to small corroded losses and a build up of corrosion products (which would be expected), the lid displayed signs of damage appearing to be caused by force. There was a missing peg revealing a circle of fresh iron and potions of the sheet metal were caved in and curled round. Though we cannot be certain how or when this damage occurred we suspect that it was caused at the time of excavation or shortly afterwards by archaeologists forcing the coffin open. The peg could have also been knocked off at a later date. Eg moving the object around the tight paces and stone walls of the crypt.

As mentioned in my first blog, Conservation Introduction, we knew that this object had to be prepared for display and then long term storage back at the crypt so we were concerned with its general appearance and aesthetic features and wanted to offer some protection against wear and tear and environmental conditions. After preliminary dust removal using a brush and vacuum, there remained a great deal of unsightly bulbous orange/brown iron corrosion products which disrupted the flat surface and obscured manufacturing features such as join edges, rims and the pegs too (Fig. 2). In order to minimise the risk of damage it was important to approach the object with the least possible force and work up until a successful result was achieved. We began simply brushing and found that stiff brushes were able to remove a significant amount of the very bubbly upper-most corrosion.

Fig. 2 Bulbous corrosion products along the inner lid rim

Fig. 3 A region of the rim where bulbous corrosion has been removed

However some lower levels were more stubborn. We used a type of rubber named Garryflex which contains abrasive grit to work more on these areas and the action also helped to reduce the pale corrosion dust created by the brushing which was trapped between the crevices of the uneven surface.

Fig. 4 Garryflex rubber blocks

Fig. 5 A portion of the coffin lid inner surface with corrosion brushed and Garryflex abrasion

Because of the pegs, the lid had been placed on its board front side down with the inside cover visible and pegs sticking up. However from brief visual examination during transportation we knew that the other side had some traces of decoration. We were hence careful not to press down too hard and tried to minimise movement in the object during our corrosion reduction on the inner lid.

The Museum of London proudly boasts that we have over 2,000,000 objects in our collections. Yeah, the British Museum might have 8,000,000 and the Victoria & Albert, 4,600,000, but still, 2,000,000 is a big number. In our conservation department, there are 20 members of staff. I’m no mathematician but even so, by my calculations that’s 100,000 objects per conservator. And those kind of numbers impress me.

In terms of archaeology there are 5 conservators whose job is to specifically focus on the “archaeological collections”. Since the archive opened in 2002, they have helped advise and design our basic methods of collections care which our volunteers are now practicing each Monday, Tuesday & Friday in Archaeology in Action (until March 23rd). But there are loads of other aspects of a conservator’s role that could make it the best job in the museum…

Conservators are a little bit like the doctors of the museum. They take things that look terribly unwell and make them better. And they always seem to be looking at x-rays.

They’re also the scientists of the museum. Or at least they look the part. They get to use liquids with warning labels and wear white lab coats.

They might be considered the magicians of the museum. On one hand they magically clean up objects that look like they’re beyond help and on the other hand they deal with objects that have magically transformed from their original state.

And one thing they most certainly are are the most photographed members of staff, always popping up with any press releases and in publications.

So, all in all, a pretty cool job (and secretly what I wanted to be when I first volunteered with the museum many moons ago) and with this in mind, I definitely wanted Conservation as part of our archive’s 10th Anniversary Celebrations. Every Monday for the next 6 weeks, you can find out why they’re like doctors (there’s some amazing x-rays on display revealing hidden objects), like scientists (find out the different techniques they use to preserve leather), like magicians (wait to you see their incredible piece of shrinking wood) and if you ask really nicely, they might even let you take a picture of them.

For more about our Archaeology Exposed events visit our website.

A blog post from Jon in our conservation team on the work looking after and preparing our objects for display.

As this years’ intern within the applied arts section of the conservation department at the Museum of London I am very grateful to have been given the exciting opportunity of experiencing the build-up and installation of the Museum’s major new exhibition – Dickens and London.

In the months before installation began, conservators were busy ensuring all the objects and artefacts were suited to being placed on display. Within the new exhibition objects of a range of materials are installed including shop signs from Dickensian London, documents written in Dickens’ own hand and furniture from Dickens’ house.

This required the knowledge and expertise of our whole conservation team, particularly specialists in paper, textiles and the applied arts.

Within the Applied Arts section we work to conserve many artefacts of Victorian social history; however, as an admirer of Dickens it has been incredibly rewarding being able to work on objects with a particularly close connection to the man himself – such as this chair he was often photographed in.

Dickens’ chair is on open display within the new exhibition, so work was required to stabilise and secure the aged leather upholstery, predominantly around the back rest, where the degraded material had begun to laminate and fall away.

In addition to this, surface cleaning was conducted to remove dust.

Modern ethics within the field of conservation maintain that minimal intervention should be practiced when conserving artefacts – this means altering the original material and structure as little as possible, whilst ensuring the object is sturdy enough to be displayed or stored. We also aim to make every process and alteration reversible, so our changes could be ‘undone’ if needed in the future. For Dickens’ chair this meant adhering loose leather with a removable adhesive to consolidate the fragile material.

Historic leather can suffer acidic degradation due to reactions with sulphurous pollutants in the air. Testing the pH of the leather of Dickens’ chair revealed the leather had become particularly acidic – it was therefore thought appropriate to treat the leather with an aluminium compound – a process that effectively re-tans the leather – neutralising acidity and reversing some degradation processes.

Preventive conservation is also a key role of the museum’s conservators and collection care staff. With regards to this we have been carefully monitoring light levels (particularly important where objects such as Dickens’ handwritten manuscripts are displayed!), ensuring the environment within the gallery is suitable for the collections and that the cases are dust free – the latter involving several days spent cleaning the inside and outside of display cases!

It has been brilliant to see the culmination of many people’s knowledge, ideas and skills work together to create such an exciting and enchanting exhibition.

You can hear more about the conservation work for the exhibition as part of our free drop-in activities for families during February half term on Thursday 16 February between 11.30am to 1pm and again at 2pm to 3.30pm.

Following on from our last blog update on the help volunteers have provided in terms of conserving parts of the PLA Archive.

We felt that the support that resulted in our diligently boxed PLA Archive volumes deserved to be highlighted in a post of its own.

Here, one of our volunteers, Kate, shares her thoughts on her time with us and the process of boxing up key PLA record books:

“It was a fantastic experience and very valuable as a trainee paper conservator to be able to have ‘hands-on’ experience of cleaning and repairing documents then building the archive boxes for long-term storage for an established museum.

I would measure the books and make each box to fit the book, making sure there was enough room around the edges inside the box to be able to fit fingers in to lift the text out. To stop the book sliding around plastazote can be slotted into the box.

Using archival adhesive I would fold the archival cardboard and stick at the edges together using clamps to hold everything in place while the glue was drying. The box was made in two parts, a base and a lid that fitted over the base.

Here is an image of a bespoke box ready to go back to the store! ”

Look out also for an update soon from Claire Frankland, Port & River Archivist and Project Manager, as this project reaches its first birthday.

Liz Goodman, Conservator:

Earlier this year I was asked to conserve three lead bale seals from Tasmania, Australia by Dr Eleanor Casella from Manchester University, UK.  I always enjoy working on finds from different clients as some of the stories associated with the objects can be very different to the objects we normally work on.  This was an extreme case with the seals excavated from the Ross Female Factory penal colony.

When excavated, the lead bale seals were covered in an obscuring layer of corrosion, so only some of the detail was visible.  It was hoped that the seals could be cleaned and prepared for display back in Tasmania.  The conservation process involved mechanically removing some of the corrosion under a microscope and then removing the remaining corrosion through an electrochemical process.

Through the conservation process, I was able to reveal the stamp of the Royal Army Ordnance Corp who provisioned the Ross Female Factory penal colony for the British Empire.  This has enabled Dr Cassella to discover much more about how the penal colony operated.  You can read more about her findings on the Bioscience Technology website: http://t.co/cL2mQqy.