Challenge of Materials? Collecting & caring for plastics at the Science Museum.

Challenge of Materials?Collecting & caring for plastics at the Science Museum. Making the most of plastics in you collection. Scottish National Gallery of Modern Art, 26th November 2007 Fran David, Conservator (Collections Care) Science Museum sciencemuseum.org.uk

Introduction • What lead to this research: The acquisition scorecard. • The key plastics and why we want to identify them. • The reference fact sheets and how they help. • The curatorial view. • Further benefits of this system. sciencemuseum.org.uk

The Acquisition Scorecard sciencemuseum.org.uk

Designing a useful reference tool • What plastics are present? • How can I go about identifying them? • Will this plastic deteriorate? • If deterioration can be seen what does this mean? • How can I reflect this in the scorecard? sciencemuseum.org.uk

Key Problem Plastics sciencemuseum.org.uk

Cellulose Nitrate • Deterioration: • Light and moisture cause loss of nitrates. • Water and oxygen then turn these into acids which accelerate deterioration and affect other materials. • Cracking and crazing can be caused by the lost of plasticiser and chemical breakdown of the polymer. sciencemuseum.org.uk

Cellulose Acetate • Deterioration: • Again releases acidic products which aid further decay. • ‘Vinegar syndrome’ • Ester plasticisers can weep • Warping is a common effect of plasticiser loss sciencemuseum.org.uk

Poly vinyl chloride (PVC) • Deterioration: • Light causes discoloration • Hydrochloric acid can be a by-product of deterioration • Plasticisers can migrate to the surface leading to both: • Weeping • Warping • Cracking sciencemuseum.org.uk

Polyurethane foam • Deterioration: • Oxidation causes discoloration • This also causes loss of strength • Moisture can also be a factor sciencemuseum.org.uk

The Fact Sheets, 3 topics: • Types of deterioration you might find • Problem plastics to identify • How to identify these materials sciencemuseum.org.uk

Types of deterioration and where you find it: • This sheet provides you with the deterioration you might find on a plastic object and an indication of what plastic this might be. sciencemuseum.org.uk

Problem plastics to identify: • This outlines the 4 key plastics: • When they were in production • The types of objects you find made from them • The deterioration you might see • Images to illustrate this sciencemuseum.org.uk

How do you identify these materials? • Here each plastic has a simple yes/no decision tree to help identify them • Storage implications are explained • If additional conservation costs are necessary these are explained so they can be applied sciencemuseum.org.uk

Handling • Always wear gloves when handling any plastics: • Not just for the objects safety but also for your own. • Know your object: • Do you know the materials present? • How might their properties have changed? • Object numbering: • Either: • Write directly on the surface using a fine wax pencil or a TRIA pen with carbon black Golden Fluid acrylic paint only • Use a water based adhesive as the intervention layer after testing that the surface is not water sensitive sciencemuseum.org.uk

General Storage • Environment: • Stability • Temp <20˚C • RH 30-50% • Exclude light • Support: • Store and support an object you know will lose flexibility in a display friendly way. • Isolation: • Keep objects that may off-gas harmful products away from other materials. • Filtration • Use filtering to reduce harmful atmospheric products accelerating deterioration. sciencemuseum.org.uk

Storage Specifics • Cellulose nitrate & Cellulose acetate: • Do not wrap • Isolate from metals and other materials if possible • Use air filtration/vapour scavengers • Poly vinyl chloride: • Do not wrap • Do not store in contact with expanded polystyrene • Store with re-display in mind • Polyurethane foam: • Oxygen-free storage options? • Store with re-display in mind sciencemuseum.org.uk

Display • Environment: • Temp & RH: • <20°C • 30-50% <5% daily flux • Light levels: • No UV • <150 lux • Display materials: • Avoid materials that could off-gas organic vapours (wood, MDF etc…) • Things to avoid: • Do not put cellulose nitrate or acetate in a case with metals or other vulnerable materials. sciencemuseum.org.uk

Case studies with Curators ‘ I wouldn’t want to leave a legacy that somebody’s got to care for. I wouldn’t acquire something lightly knowing that in 20 years time somebody’s going to have to spend time and money looking after it.’ sciencemuseum.org.uk

Forestry raincoat • The raincoat posed a number of questions for the curator: • This could not be displayed in it’s condition so should it be disposed of? • What is the significance of the object? Does it have a personal attachment? • If not, should another be acquired if this is going to happen again? • Has there been a change in importance, from type of protective coat to technology of the material? • Would this be a reason to keep this specimen? sciencemuseum.org.uk

Try to acquire those plastics identified as ‘at risk’ in good condition. Store in a way that will enhance the object’s useful lifetime. Inform all parties about the potential longer-term problems. Analysis of unidentified materials should be budgeted into process. Objects acquired for exhibition which are identified as having stability issues should only be acquired as auxiliary material so that it can be disposed of when the exhibition closes. Objects incorporating ‘smart’ plastics should only be acquired if we have been able to get materials information from the manufacturer. Avoiding problems: sciencemuseum.org.uk

In practice: Appropriate display: Appropriate storage: Accurate care costs with realistic expectations of lifetime & display: sciencemuseum.org.uk

Conclusions • The fact sheets are helping us improve our collections care by increasing our ability to assess unfamiliar materials. • Because we ask the curators more questions, we get more detailed material information to plan our treatments and care on. • Greater understanding between curator and conservator when an object is acquired can prevent conflicting opinions in the future. • The fact sheets are also helping to inform our storage and care strategies for objects already within our collections. sciencemuseum.org.uk

Thanks to: Sue Mossman Hazel Newey Jannicke Langfeldt The support of the Objects Clinic sciencemuseum.org.uk

Web Resources • General care of plastics: • http://www.conservationregister.com/careplastics.asp?id=4 • http://palimpsest.stanford.edu/waac/wn/wn24/wn24-1/wn24-102.html • http://www.plastiquarian.com/ind6.htm • http://www.plastiquarian.com/survey/survey.htm (labelling info not current but otherwise useful) • Textiles containing plastics: • http://www.uri.edu/hss/tmd/20th%20Centry%20Plastics.pdf • Oxygen-free environments: • http://www.cwaller.de/english.htm?oxygen.htm~information • http://www.conservation-by-design.co.uk/productlist-oxyfree.html sciencemuseum.org.uk

Challenge of Materials? Collecting & caring for plastics at the Science Museum.