Mini Post No. 6

So I have been researching about Polyvinyl chloride (PVC) over the past while and I came across this lovely example in the lab of the major danger associated with PVC. Many of us have our family photos kept in ‘plastic’ photo albums – most of these are going to be made from PVC. The biggest danger to our valuable family photos isn’t fire or theft, its the album itself! The plasticizer is very prone to migrating to the surface of PVC, if it’s not removed it forms what’s known as sweat beads. These beads destroy photos! Take a look at the two images below to see just what kind of damage can be caused!

Later in the month I’ll do up a more detailed blog post about PVC. Till then, if you want more information about how to protect your photographs have a look what the British Library and The National Archives have on the topic.

A photograph has been totally distroied by the migraetion of plastizer from the album sheets. (c) Victoria and Albert Museum, London.

The photograph has been totally destroyed by the migration of plastizer from the album sheets. (c) Victoria and Albert Museum, London.

Close up on the face of a person in the photograph. The image had lost almost all definition. (c) Victoria and Albert Museum, London.

Close up on the face of a person in the photograph. The image had lost almost all definition. (c) Victoria and Albert Museum, London.

 

Mini Post No. 5

We collect a lot of samples during the year and these days we store them in little plastic resealable bags or if they are really small we put them in clear gelatin capsules… But back in the days before plastic (and in an era where more people smoked!) we used matchstick boxes.

Matchstick samples

Old samples have been placed into matchstick boxes to keep them organised and safe 🙂

 

Kaleidoscope House – A dolls house for the ‘child’ interested in modernist architecture

One of the nicer elements of my job is the exposure to the wonderfully diverse collection that we have here at the V&A. Later in the year the Museum of Childhood is putting together a wonderful exhibition on Dolls houses. We (my supervisor and I) were asked to consult on one of the more unusual dolls houses that will make up the exhibition – Kaleidoscope House

Kaleidoscope house - a mini modernist masterpiece (say that 10 times fast!)

Kaleidoscope house – a mini modernist masterpiece (say that 10 times fast!)

The example of Kaleidoscope House that we have here at the Museum of Childhood does not have its artwork attached to the walls. As they were purchased separately the museum could not, in good faith (ethics and all that!), adhere the artwork to the plastic walls without investigating how the artwork, adhesive and plastic would react over time. I was set the challenge to devise a simple and quick experiment to do this.

When we talk about the lifetime of a collection or an object we need to look timelines beyond our own lifetimes or careers. Research into this topic indicates that people would like an object to survive in a “usable” form for 100-500 yrs. Clearly we can’t wait around to see how objects react to their environments, nor can we always look to the past as we may not know the exact conditions of storage. This is where artificial aging comes into play. We know that exposure to light, especially UV light, is very damaging to plastics (and to objects in general. I can’t believe I just linked to the Daily mail…). We also know roughly the amount of light an object will receive when on display:  50 lux for 10 hours a day for 365 days = ~180Klux per year. By placing objects in a light box, exposing them to very high light levels we can mimic the the effect of years of light exposure in a short period of time. There are other factors which are important, temperature and relative humidity being the other two major effects. I wont go into more detail and risk boring you all but Robert Feller has a very good book on the topic of Accelerated aging which you can find for free here and it’s well worth a read, even if it’s just to brush up on the basics of what tends to age things!

Anywhos… back to my plastic dolls house. Through a bit of research – basically procrastinating while reading the wonderfully in-depth world of mini modernist houses over at http://modernminihouses.blogspot.co.uk/ we confirmed our theory that the walls were made of polystyrene, a common plastic used for this type of application. The experiment was a simple idea – get materials similar to those intended to be used, test a range of different adhesives and expose everything to 5 years’ worth of light! CD Jewel cases are also made of polystyrene allowing us to use cd cases that we had here in the lab – to better match the current conditions of KH we used cases that were of similar age. The amazing people over in the paper conservation department gave me some mount board of a similar thickness to the artwork; they also provided three common adhesives used in paper conservation – wheat paste, EVA and Methyl cellulose. The other interesting adhesives we tested were blue tack (yup, regular blue tack!), Paraloid b72 (a very common adhesive used in conservation) and Sugru (a new silicon based adhesive a bit like blue tack, only yellow and much stronger/permanent. It is also very popular in the hacking community atm.)

CD case ready to be tested - note that I used an excess of adhesive to see the 'worst case scenario' when trying to remove the 'artwork'. In real life you would try to use much less adhesive than this. (c) Victoria and Albert Museum, London.

CD case ready to be tested – note that I used an excess of adhesive to see the ‘worst case scenario’ when trying to remove the ‘artwork’. In real life you would try to use much less adhesive than this. (c) Victoria and Albert Museum, London.

CD jewel cases in the light box, propped up so that front and back get similar light exposure. You can see that a few of the adhesives have failed right from the beginning! (c) Victoria and Albert Museum, London.

CD jewel cases in the light box, propped up so that front and back get similar light exposure. You can see that a few of the adhesives have failed right from the beginning! (c) Victoria and Albert Museum, London.

After leaving the test to run for 96 hours (who wants to do the math to work out the average light levels in the light box…) we then tried to remove the mount-board and the adhesives. Before starting the tests I thought that wheat paste would work the best – how wrong was I! It was the 1st to fall off, along with Methyl cellulose – they didn’t even last a day!

Sugru was very difficult to remove, and I really thought I’d crack the plastic – I didn’t, but as you can see below I couldn’t remove the mount-board cleanly. Removing EVA was very similar and the risk of cracking the plastic rules these two adhesives out of contention.

Sugru...I was able to remove this from the plastic CD case, but not the paper artwork - it wouldn't want to be a Constable painting i was trying to take off! (c) Victoria and Albert Museum, London.

Sugru…I was able to remove this from the plastic CD case, but not the paper artwork – it wouldn’t want to be a Constable masterpiece I was trying to remove! (c) Victoria and Albert Museum, London.

Blue tack left a nasty residue behind. Researching into what goes into blue tack we found out that it contains a small amount of Xylene. Have a look at the video below to see what happens (admittedly in a pretty extreme case) when xylene and polystyrene come into contact with one another! Not what you want to have happen and leaving the residue on the surface would increase the risk of localized damage to the object.

You can clearly see the residue left behind on the surface! (c) Victoria and Albert Museum, London.

You can clearly see the residue left behind on the surface! (c) Victoria and Albert Museum, London.

So after all that work we found out that none of the major adhesives were suitable for this project (what was it that Thomas Edison said…) . In fact some of them could have totally ruined our lovely dolls house! The curators were thankful for the information we had given them, but also a little sad as they are now back to square one. We think we might be able to hang some of the artworks using nylon wire (again, a pretty common thing to do). The risks to the object are increased the more times the blue roof has to be taken on and off, but it also means we won’t have access to hang every piece of art. A small price to pay for keeping this lovely object in great condition! You can come see what methods we used when the exhibition opens later in the year.

Mini Post No. 4

The nice people over that the Getty Conservation Institute have just released their new newsletter for Spring 2014. It deals with all things plastic and has a great article on the research they carried out on animation cels from old Disney films. You can find a pdf of the newsletter here.

In other news…

The science conservation department of the V&A has the most fantastic collection of cross-sections. These would have been originally used during the analysis of museum objects and are now kept as references for future work. Some of the cross-sections, which are no more than 20mm wide, have 10+ samples in them!

 (c) Victoria and Albert Museum, London.

(c) Victoria and Albert Museum, London.

 

Why conserve Plastics?

So then, Plastics… Why do we need to conserve things that we have been told last for hundreds of years in rubbish dumps?

Well it turns out that some plastics don’t last that long at all! In fact rather than thousands of years we can be talking about very short lengths of time.

The key thing to note from the guardian article is this line – “These are plastics made to degrade in the presence of oxygen and sunlight, thanks to the addition of tiny amounts of metals like cobalt, iron or manganese.” In other words, engineered impurities that lower the lifespan of the object, with oxygen and sunlight (read: UV light) doing the real damage.

Plastic objects that we find in museums mostly likely will not have these impurities engineered into them, but through poor manufacturing techniques – typical of the early plastics, will have them naturally. (See sections 2.6 & 2.7 here)

The degradation of plastics can take many forms, but most lead to some pretty dramatic end results! Take this object for starter;

A Plastic handbag from the teaching collection here at the V&A... We actually wanted it to get this bad! (c) Victoria and Albert Museum, London.

A Plastic handbag from the teaching collection here at the V&A… We actually wanted it to get this bad! (c) Victoria and Albert Museum, London.

When I arrived (in a more nervous from that normal) to my interview here I was given a tour of the lab – that was February, and back then it still had its clear lid attached and its form was such that one knew it was a handbag. Now it’s mostly dust…

The most worrying aspect of this type of decay is its effect on its surroundings. We see below that when plastics degrade they can also cause the corrosion of metals in the surrounding area. This is a very important behavior that must be taken into account when we store plastics.

Corrosion of metal that can sometimes be associated with degrading plastics. (c) Victoria and Albert Museum, London.

Corrosion of metal that can sometimes be associated with degrading plastics. (c) Victoria and Albert Museum, London.

Over the course of the next year or so I will mention a couple of ‘technical’ terms…I say technical because in the context of plastics conservation they have exact meanings – yellowing is pretty obvious, but in this context it implies a method of decay and also its results.

Here we see some packaging foam which shows (additional) yellowing over the area exposed. (c) Victoria and Albert Museum, London.

Here we see some packaging foam which shows (additional) yellowing over the area exposed to light. (c) Victoria and Albert Museum, London.

One of the more impressive forms of decay is “crazing” :

Glasses from the teaching collection with crazing around the  nose bridge. (c) Victoria and Albert Museum, London.

Glasses from the teaching collection with crazing around the nose bridge. (c) Victoria and Albert Museum, London. (c) Victoria and Albert Museum, London.

This happens when the plasticizer used during manufacture evaporates away, water molecules take its place, hydrolysis starts and as a result the plastic just turns to dust.

We may not realize it but plastics can be found in object that we may never have thought would contain them. Quite a lot of furniture can contain plastic foam as the cushion. The major problem with this is when it starts to decay and break apart. In the image below we see the imprint of my thumb, if I were to push further or move the foam in another way it would simply crumble away – now consider that many pieces of 20th century furniture contain this material…

Damage to Foam

Thumb imprint in foam packaging. (c) Victoria and Albert Museum, London.

One of the more disgusting methods of decay is called sweating;

Result of sweating

Sweating can lead to dust and dirt sticking to the surface of the plastic; this can be very difficult to remove. (c) Victoria and Albert Museum, London.

This when the plasticizer or other additives migrate to the surface of the object; they can form beads of liquid on the surface which in turn trap dirt, dust and particulates on the surface of the object. These are extremely difficult to remove from the surface.

Along with these specific types of damage we also find that plastics are just as vulnerable to regular damage as anything else. We get the normal cracks and chips that we find in objects made of other materials:

Crack and Crazing

A crack formed in the center of of a plastic box, note the crazing surrounding it. (c) Victoria and Albert Museum, London.

Lastly, the problem we most face with plastics is simply a build-up of dust and dirt.

General Dirt

Regular dust and dirt buildup on the surface of a plastic box. (c) Victoria and Albert Museum, London.

This is an area that causes many issues within the field as little has been done to study the effects of different cleaning techniques and materials. POPART made a very good start at investigating what could and more importantly could not be done. A major part of my internship will be repeating some of the POPART experiments and as such you will see a lot of the results here.

PS: The objects you see on the blog are mostly taken from our ‘teaching’ collection here in the lab. One nice thing about plastics is that as they were so widespread that we can pick up old objects in car boot sales and the like, and sacrifice them in the name of research!

Mini Post No.2…Back to Black

Today I tested some of the different ratios of of Paraffin oil and carbon black, a standard soil, that have been mentioned in literature. Once the ideal one has been chosen I can used it in my cleaning experiments. The % quoted in the photo below is the wt% of paraffin oil used.

Different ratios of soiling (paraffin oil and carbon black) are being tests to see how long they take to dry and how evenly they can be applied

Different ratios of soiling (paraffin oil and carbon black) are being tested to see how long they take to dry and how evenly they can be applied