This week we have the final part of Project Conservator Mhairi Boyle’s series on the conservation treatment of three Percy Johnson-Marshall architectural models. The first part can be read  here.

Putting the Pieces Together: The Challenges of Working on Architectural Models (Part 2)

In my last blog, I introduced the Percy Johnson-Marshall architectural models, and the challenges faced when designing a treatment plan for them. In this week’s blog, I am going to tackle the topic of different adhesives and treatment methods used in this project.

In the field of paper conservation, there are a few gold-standard adhesives. The most ubiquitous adhesive that almost all paper conservators use is wheat starch paste. Though most conservators associate starch-based adhesives with East Asian conservation practices, one of the earliest recorded uses for starch was recorded in Ancient Egypt, where it was used to adhere pieces of papyrus together.

Powdered wheat starch mixed with water over heat forms a gelatinous paste, which can be tailored to suit different purposes. It can be kept thick (‘dry’), or thinned out with more water. Dry paste is often used to mend thicker paper-based objects or objects which cannot tolerate a lot of moisture, and thinned out paste is used when more flexibility is required. I decided to use a very dry paste to attempt to re-adhere lifting areas of the models, with varying degrees of success. Wheat starch paste requires at least 10-15 minutes to dry, meaning that the part of the object being repaired with paste needs weighted down. Although wheat starch paste is a strong and reliable adhesive, the extent of the water damage and the embrittlement of the card used in areas of the model meant that it was not strong enough to re-adhere parts of the model.

Collections Care Assistant Sarah Partington and I then moved onto using EVA glue. EVA stands for ethylene-vinyl acetate. It is a synthetic adhesive that was adopted by conservators in the 1980’s as a more reversible (but still challenging to remove) alternative to the completely irreversible PVA (poly-vinyl acetate). EVA is commonly used

Loose and lifting areas of one of the models.

in book conservation and artefact conservation. It’s stronger than wheat starch paste, but also has a longer ‘curing’ time. Rather than ‘drying’, adhesives like EVA and PVA react with the environment and form flexible solids.

Using EVA worked in some cases, but again, the drying time was not quick enough for the thicker cards used on the model. We also found that the weights we were using during the drying process were not quite the right size. At this stage, I turned to our Musical Instruments Conservator Jonathan Santa Maria Bouquet for some assistance.

Jonathan has experience dealing with an incredibly dynamic collection of 3D objects, chiefly musical instruments, and his workshop reflects this. Whereas paper conservators often have nimble and petite tools in their arsenal, Jonathan has saws, drills, clamps, and hammers.

Custom acrylic weights made by Jonathan Santa Maria Bouquet.

He very kindly lent Sarah and I some clamps to hold areas of the models in place while drying and created some custom-shape acrylic weights for us to use.

In addition to this, Jonathan suggested we try the adhesive Paraloid B72. B72 is an acrylic resin which has been used in conservation for over 25 years, and is commonly associated with archaeological and objects conservation. It is manufactured as small hard pellets which are then dissolved in a solvent of choice. Solvents are chosen based on how quickly they evaporate and their compatibility with the object – the quicker a solvent dissolves/dries, the quicker the adhesive will dry. Jonathan recommended a 50/50 mix of acetone and isopropanol, to give a medium-fast drying time.

From left to right: wheat starch paste, EVA, and Paraloid B72.

The B72 was a success – in conjunction with the custom weights and clamps, Sarah and I managed to successfully adhere all loose components of the models. It dried quickly, and the clamps and custom weights allowed us to apply a stronger and more precise amount of pressure to drying areas.

Clamping an area of the model to allow the Paraloid B72 to dry.

Successfully re-adhered components.

Acid-free tissue was built up to create an even plane, reducing the risk of pieces coming loose.

After the models were made secure, Senior Collections Manager Katharine Richardson and I met to discuss the safe packing and moving of them. Sarah and I prepared for their move by covering them in acid free tissue, filling in any gaps between built-up areas so that they wouldn’t come loose and knock against each other. The external removals contractors then arrived, and we discussed the safest method of moving the models. Large plastic bags were used to cover the models and tissue, and everyone held their breath as the largest model was tipped on its side to fit through the door.

Everything remained secure, and the models made it safely to the University Collections Facility. This project demonstrated the importance of cross-disciplinary collaboration and wouldn’t have been possible without the whole team mucking in to put the pieces together.

Sarah and one of the models, all in one piece!

Further Reading:

Whitten, J., Buckley, B., Houp, H., Vagts, L., Irgang, H., van Gelder, M., Blakney, S., Roth-Wells, N., & Pocobene, G. 1997, Varnishes and Surface Coatings: Polymeric Varnishes, https://www.conservation-wiki.com/wiki/Varnishes_and_Surface_Coatings:_Polymeric_Varnishes

Koob, SP. 2009, ‘Paraloid B-72: 25 Years of Use as a Consolidant and Adhesive for Ceramics and Glass.’, in Ambers, J., Higgitt, C., Harrison, L., & Saunders, D. (eds) Holding It All Together: Ancient and Modern Approaches to Joining, Repair and Consolidation, London: Archetype Publishing, Ltd., pp. 113-119.

Menei, E. 2017, ‘Use of East Asian materials and techniques on papyrus: Inspiration and adaptation’ in Adapt & Evolve 2015: East Asian Materials and Techniques in Western Conservation, pp. 118–27.

Today’s blog post concludes Lyell Intern Joanne Fulton’s two-part series on the Lyell Project. Joanne discusses the variety of work she carried out over the last few weeks of her internship at the CRC.

As my internship at the CRC draws to a close, I can reflect on the many exciting opportunities I’ve had to experience all aspects of the work involved in conserving the Lyell Collection. As I shall discuss further in this second blog, my responsibilities have not solely covered the rehousing of the specimens in the geological collection which was explained in my first blog.

In my last blog, I spoke of the labels on the Lyell Geological specimens, some of which were more fragile than others. In twelve cases, these labels needed to be conserved and re-attached. To do so, I needed an adhesive. While I tested both gelatine mousse and EVA, a co-polymer adhesive commonly used in bookbinding. I chose to use gelatine mousse as I found it to have the strength required and was more historically appropriate than EVA, as the labels had previously been attached with an animal glue.

The labels offered a few different challenges and solutions. Following the discovery that white tack was attached to one of the rocks previously, upon closer look at the labels I found one of these labels had used blue tack to be secured to the specimen. Once I had carefully removed both the blue tack from the specimen and label, I made the decision not to reattach the label but to slip it into a Melinex pocket, which I then housed with the specimen in its box.

A specimen of grey and red laminated sandstone had an awkward placement of its label, meaning the label had suffered more damage than others being only half attached to the specimen. Here, I had to piece together the small parts of paper broken from the label, not dissimilar to a jigsaw, then use a lining to attach this with the remaining half of the label still on the specimen using a thin Japanese paper and the gelatine mousse. As this still meant half the label was not attached to the specimen, as originally intended, I created a little Melinex protective box, so the label could not be accidentally torn in the future.

Before, During and After rehousing and conservation of specimen EUCM.0167.2013

On two other occasions I used a lining to reassemble torn and broken pieces of the labels back together. Some were harder to correctly position together due to the nature of each piece and/or some parts being missing.

Applying the jigsaw-like pieces of a label to a lining

The rehousing and conservation of the Lyell Geological specimens was finished by the end of week six of my internship. With the rehousing finished, I hand-made two book cushions with Tyvek and the excess Plastazote scraps and offcuts. This created a sustainable solution with the waste material, all I needed was a needle and thread.

Book cushions proved to be a simple and sustainable solution to all the waste Plastazote offcuts

My attention then turned to Lyell’s personal notebooks and volumes. Here my aim was to rehouse them whilst gaining new skills in book conservation, skills I was very eager and grateful to learn.

The main aim with the notebooks was to finish their rehousing, not a small feat as 294 book shoes needed to be made in total. However, as this was a task completed progressively throughout the project by all those involved, all book shoes were made by the end of my week seven. As well as this rehousing, I conserved three of Lyell’s notebooks. This consisted of surface cleaning, consolidation of red rot (a degradation process found in vegetable-tanned leather), label repair, corner repair, and repairing inner joints.

Finally, the volumes needed new housing in the form of phase boxes, which provide an additional layer of support and protection to the series. Then, depending on each volume, I surface cleaned, consolidated red rot, and repaired the outer joints. For the outer joints, I used a lightweight paper which I had toned using acrylic paints to match the colour of the volume. Unfortunately, the spine and the leather on the covers were different shades, so I matched my repair paper to a mid-tone. The darker spine is unusual, as usually you see the spine is lighter because of light damage. However, in this case, I believe the spine had previously been consolidated or brushed with a substance that has darkened over time.

Example of a phase box

Having applied the repair paper to the outer joints with EVA, they were left to dry before being trimmed.

My experience at the CRC has improved my skills as a conservator immeasurably, and, boosted my confidence. The highlight for me has been rehousing the Geological collection which was a new experience and challenge, and I leave happy in the knowledge that each specimen is now preserved for the future in its own uniquely carved housing.

Today’s blog post concludes Lyell Intern Sarah MacLeans’s two-part series on the Lyell Project. Sarah discusses the variety of work she carried out over the last few weeks of her internship at the CRC.

With my conservation work on Lyell’s correspondence finally being successfully completed in the sixth week of my time at the CRC, I’ve been able to devote the final fortnight fully to – well – to everything else!

My time in this internship has not, of course, been devoted to Lyell’s letters alone. In fact, I have had ample opportunity to pursue work in many other areas of this exciting collection.

Here I am applying Klucel G in IMS to areas of a notebook cover affected by red rot.

I’ve made the journey out to the King’s Buildings Campus to handle the packing and transport of geological specimens. I’ve made innumerable journeys elsewhere too, gaining insight into the work ongoing at institutes like Historic Environment Scotland as well as the National Library, Museums, and Galleries of Scotland, and forged professional connections with the wonderful staff members there. I’ve boosted my technical skill immeasurably in book conservation, assessing and conserving three of Lyell’s personal notebooks as pictured here. And I’ve rehoused vast quantities of these notebooks by creating book shoes, a bespoke enclosure which protects the notebook but leaves the spine exposed.

After all that excitement, the last big task for me to complete during my time at the CRC has been a comprehensive survey of Lyell’s expansive collection of offprints – a very big task indeed!

An offprint is a separate printing of a work that has originally appeared as part of a larger publication, usually one created by multiple authors – like a magazine, an academic journal, or an edited book. Sir Charles Lyell understandably picked a lot of these up throughout his life, and they range far and wide in subject matter from treatises on the molluscs of Algeria to ruminations on the temperaments of the citizens of 19^th Century Reykjavik.

A selection of Lyell’s Offprints in their original state prior to survey and rehousing.

The Offprints also range in physical size from folio (approximate to A4) down to manuscript (more or less A5), a fact that caused initial confusion as the two sizes were alphabetized and housed separately as two different series. And finally, the Offprints range considerably in overall physical condition.

On the whole, they have held up well over the last two hundred years with 12 of the 18 boxes surveyed rating as Grade Two – Fair Condition. The majority of Offprints within this category are reasonably stable, can be handled safely with just a little extra care and attention, and, by and large, show mainly cosmetic or minimal structural damage at worst.

An oversized item that has suffered damage and planar distortion as a result of insufficiently large housing

However, this is not the case across the board.

One issue that I have encountered already in my survey is the issue of size, finding oversized items to be much more common within this series of the collection than initially anticipated. Oversized bound works like that pictured in figure 3 have become distorted and damaged when forced to fit unsuitable housings. Even with time-consuming flattening and other conservation treatment, they will remain too large to fit comfortably within their new housings – so alternatives must be found. As is the case with other oversized flat works like maps and geological diagrams, such items require a great deal of thought and collaboration, leading to a great many conversations with other departments within the CRC to negotiate alternative storage space within available plan chests.

A group of offprints severely affected and embrittled from damage caused by mould.

Another issue that has arisen within this survey is that of the damage caused by mould which, unfortunately, I have discovered within 11 of the 18 boxes surveyed.

I should stress, first and foremost, that the mould I’ve found is historic and entirely inactive. Environmental controls in place within CRC stores have successfully stopped the historic mould in its tracks, depriving it of the warm, humid conditions in which it likes to spread, and ensuring that it can cause no more bother than it already has.

The main challenge that the mould poses now in terms of interventive conservation treatment is the time-consuming surface cleaning process that is now necessary to safely remove it. The mould, although inactive, can appear gritty and is potentially abrasive, so it needs to be removed along with surface dirt in order for the weakened paper substrate underneath to be repaired properly. This, unfortunately, lengthens overall treatment time and potentially complicates the recommendations that I would make about the treatment and care of this part of the Lyell Collection in the future.

Surveying Lyell’s Offprints has been a pleasure not in spite of these unexpected challenges but because of them. The unexpected is something that all archives, libraries and other institutions have to contend with often – as collections grow and become more varied, it can be increasingly difficult just to figure out the extent of what you have, let alone how to handle, and treat it all! The unexpected is also something that I will encounter on a personal level, having now completed my internship and looking to make my next career step as a paper conservator. I’ve gained such invaluable and varied experience throughout my time at the CRC, the challenge of the unexpected is one that I’m now more than ready to meet head on