Many plastics are far from perfect for museum and archival use. They are applied underneath the object, then the object is pressed down to the horizontal surface. This unobtrusive method can be a short- to medium-term solution for waterproof and smooth surfaces such as glass, metal or coated metal. Plastics are synthetic compounds made of long molecular chains called polymers. Sintra) are not recommended for use in contact with objects for long-term purposes (limit their use to five years maximum). For aesthetic reasons, the interleaf should not be visible to the viewer. No. Raise enclosures 10 cm (4 in.) Instead of being able to break a window or display case in one hammer strike, it may take more than 10 strikes to get through the secured glazing. A natural rubber shoe sealed in a bag made of multi-layer film to protect against oxidation or any outdoor pollutants. airtight (protection against external pollutants and insects and to some degree against large RH fluctuations); waterproof (if not stored in a waterproof cabinet or not covered by a plastic sheet); strong enough to support the weight of objects they contain when lifted, plus other possible loads (such as the weight of one or two other boxes potentially placed on top); labelled to allow ease of identification during retrieval; and. Support for archaeological objects made of crosslinked polyethylene foam. Paint films should only be tested after airing for a one-week period to ensure that most of the early-release volatile compounds have dissipated. : CH57-3/1-32-2017E-PDFISSN 0706-4152ISBN 978-0-660-04138-4. To determine if a fabric, paper or matboard (whether wet or dry) could transfer dye to objects. Coatings are often applied on wood, metal and concrete surfaces for aesthetic purposes but also to protect the substrates and to block potentially harmful compounds that can be released by wood products. The aluminum can also be used to seal and block the transfer of potentially harmful products from different materials, such as papier-mch, to objects, as shown in Figure 16. It is also less transparent and less reliable. Wet the lead acetate test strip with one or two drops of clean water. Overloaded lines (monofilaments) and strings can break prematurely. There are not many tests recognized by the conservation field to investigate whether products contain harmful compounds. In general, when ambient RH is well-controlled, adequately coated wood and wood products should be acceptable for enclosing most objects, except those containing lead. However, sometimes, there may be more harmful volatile compounds released by coatings than by the wood itself. Tyvek is thin and has good strength; it is often used for rolling textiles and can also be used as a dust cover in collection storage. For example, some productsand objectsdeteriorate after a period ranging from a few years to a few decades, and this deterioration causes an increase in the rate at which pollutants are emitted. If the stated drying periods are hard to fulfill, the best option is to use an interleaf between the surface and the object. Figure 23. This undesirable pattern can be quite noticeable, affecting the appearance of the object. A change in a products properties over time is caused or influenced by four factors: Because certain deleterious properties of a product may evolve to become significant or insignificant over time, the product may be used in proximity to objects during the time frame when it does not cause significant adverse effects, while avoiding it otherwise. Ottawa, ON: Canadian Conservation Institute, 2010. The initial wet pH should be at least 6. Some special polypropylene films have a reduced-glare finish for increased visibility of documents. His main research interests focus on pollutants, products used for display and storage, paper degradation and passive environmental controls in collections. However, adhesives used in an enclosure should be allowed to off-gas or dry out (cure or set) for three to four weeks, especially if there is a large surface area to be glued, before sensitive objects are placed in the enclosure. Ethafoam is also available in different densities. CCI 120171-0013. A hot iron is applied to plastic-laminated aluminum foil to melt the polyethylene side of the foil onto the plywood panel. Polyester quilt batting is wrapped over a polyethylene carved foam shape to provide a soft-padded surface for an internal shoe mount. High-density polyethylene hard boards or panels are popular choices when strength and rigidity are needed, e.g. Ideally, biodegradable products should not be used for conservation to avoid unwanted results. Matboard is a paperboard typically used by the picture framing field as well as in conservation for mounting and storing works of art on paper and photographs (folders, window mats) and, in glazed frames, for increasing the gap between the mounted artwork and the glass. Damage reported in ambient conditions. Wrapping a rolled textile with two to three layers of acid-free or alkaline-buffered tissue paper provides an effective, low-cost barrier against dust and reactive outdoor pollutants, such as ozone and nitrogen dioxide. When bubble wrap is placed in direct contact with objects or held taut against surfaces for long periods, there is a risk that stains in the shape of the air cells can become imprinted on objects (Figure 25). Security films applied on glass panels or windows help to impede access into the building or inside a display case. CCI 88702-0154 Products used to treat objects are not covered here, nor are electronic features such as lighting and security devices. In particular, it provides a degree of protection against opportunistic thieves and vandals, especially if the panels are physically fixed to the base of the cases. When the skin of the foam is cut, the new foam surface may be too abrasive for very delicate objects. CCI Notes 20/2. Government of Canada, Canadian Conservation Institute. CCI 120260-0334 (In contrast, cell cast acrylic is recommended for framing and display cases because of its superior optical clarity.) Government of Canada, Canadian Conservation Institute. Plastic products appear throughout museums in various forms such as: adhesives, coatings, fabrics, foams, gaskets, panels, sealants, sheets and lines. For polyethylene (PE) foam board and polystyrene (PS) insulation foam board, consult Foam planks, thick (>13 mm or 1/2 in.). If these are observed, this confirms that the fabric contains compounds that should be removed prior to its use within collections: wash the fabric and redo the test to check that all residues have been removed, or select another prewashed fabric that passes this test. It is also wise to avoid stacking many boxes on top of each other, as shown in Figure 17. An alternative sustainable practice would be to reuse the regular polypropylene or to recycle it properly. However, before choosing your materials, a proper risk assessment needs to be made. Tyvek also has various other uses as described under the section Films, sheeting, sleeves and envelopes. You will not receive a reply. Elm, maple, poplar, ash and aspen are some of the Canadian species that usually have a pH above 5. Rigid, tough products are often padded where they come into contact with an object. Coloured translucent and opaque acrylic and polycarbonate sheets are available, as well as those with a mirrored look. Risk analysis would be required to determine whether these products provide more benefit than risk, such as the possibility of failure and stains on the objects. Green, L.R., and D. Thickett. Conservation and preservation publications, Canadian Conservation Institute (CCI) Technical Bulletins, Principles for selecting products for preventive conservation, Assessing the vulnerability of the objects, Assessing potential threats from products, List of products used in preventive conservation, Poly(methyl methacrylate) (PMMA and acrylic), Poly(ethylene terephthalate) glycol (PETG), Poly(methyl methacrylate) and polycarbonate (PC), Selection of coatings based on substrate and purpose, Where to buy products for preventive conservation purposes, Tests for products used in preventive conservation, Test #1: Lead acetate test for detecting sulfur compounds, Test #2: pH test using glycerol for measuring the acidity of volatile compounds (Ttreault 1992), Examples of preventive conservation practices, Plastics gifts of the 20th century and challenges of the 21stcentury, Plastics gifts of the 20th century and challenges of the 21st century, Test #2: pH test using glycerol to measure the acidity of volatile compounds, Test #2: pH test using glycerol for measuring the acidity of volatile compounds, Sustainable Use of Coatings in Museums and Archives Some Critical Observations, Agent of deterioration: incorrect relative humidity, Step 5: Use Cushioning Material Effectively, The Society for the Preservation of Natural History Collections (SPNHC), CAMEO (Conservation and Art Material Encyclopedia Online). Figure 44. Stratocell foam can be produced in thicknesses from 25 to 203 mm (1to8 in.). A twined basket with a silk lining, stored within a custom-made box constructed of acid-free corrugated paperboard. Figure 2 represents these phases based on products emitting acetic acid. They are often made of formaldehyde-based resins such as phenol formaldehyde and/or melamine formaldehyde, and they are not problematic (emissive or corrosive). In the first years of the 21st century, about 275,000 objects from two museums were moved to the new Muse du Quai Branly in Paris. Products that contain sulfur, such as vulcanized rubber, should not be placed in contact with objects and should not share the same enclosure, whether airtight or leaky. has a pH slightly above 7.0) to protect paper from acidity is appropriate for most works on paper. To determine the acidity of volatile compounds from a specific product, enclosure or room. Flexible poly(vinyl chloride) (PVC) is to be avoided for preventive conservation use. CCI 126389-0039, Government of Canada, Canadian Conservation Institute. Those made of a thin layer of polystyrene adhered to the foam core can be used safely in terms of minimal risk of off-gassing. In this section, three tests for detecting harmful compounds in products (sulfur compounds, volatile compounds and non-waterfast dyes) are presented. A common method to reduce emissions from wood and wood products is to seal them with a coating or to buy them already laminated (for information about Formica and melamine laminates and medium- and high-density overlaid plywood [MDO and HDO], consult Coatings, laminates and films). Wooden and concrete floors: Two-part epoxy paint can be chosen if there is a requirement for good chemical resistance, and two-part urethane is recommended for good abrasion resistance. Some large panels made of polycarbonate (such as Verolite) and acrylic are available and are used for building structures (twinwall or multiwall) such as greenhouses. High-density PE (HDPE) tends to have a greater lifetime than low-density PE (LDPE). Other types include metal panels, which are ideal for applications requiring strength and durability, and composite panels, which are ideal when looking for lightweight panels that remain rigid without bowing, even when used in extra-large dimensions. Many types of foam are available with differing densities (hardness) and compressive strengths. salt): efflorescence, Lead glazed ceramics: salt efflorescence on the glaze, Wood (oak and cedar being among the most acidic) and wood products (such as plywood, particleboard, cardboards and papers), Many types of fresh coatings (oil-based paint being the most acidic), Acetoxy cure silicone sealants (universal type, which release acetic acid), Vinegar-based cleaning solutions (sometimes labeled as green cleaning products), Cellulose nitrate film or object: crystal growth, disfigurement of image, Linseed oil (e.g. glycerol). Some corrugated plastics are specially made to be biodegradable, such as the Hi-Core Oxo-Biodegradable. The weakest point of the boxes is the stress at bent edges. The trade name Saran Wrap used to be the most common stretch wrap on the market, and it was originally made of PVDC. Ttreault, J. For example, a 20-year-old urethane gasket, shown here, that was kept in the dark and in stable environmental conditions is now falling apart. Fabrics, including jersey knits, plain weaves, felts and velvets, as well as non-woven materials such as Tyvek, are commonly used as finishing materials, providing an aesthetically pleasing soft covering layer or interleaf and in some cases providing a certain amount of padding. If the product is used to physically support an object, it must provide adequate support and a sufficient area of contact to avoid deformations or stresses due to gravity or handling; the points of contact should not cut, scratch, dent or deform the objects surface; and the product should be strong enough to support the weight. Strings and wires are generally not used directly in contact with objects but can be useful to assemble products together when making boxes and enclosures. Ottawa ON K1B 4S7 It is important to realize that no wood can be referred to as being of museum-quality. Formaldehyde-free wood products are beneficial in terms of human health but not usually for objects. CCI 120171-0022 For example, if a large copper object is in contact with an iron wire, the wire will corrode at the contact point when exposed to high humidity since iron is less noble than copper. This can be caused by a combination of factors, such as the aging of the product or string, a localized weak point or stress on the supports joint or at the knot in the string. A Melinex window on the top or (as shown here) on the side of a storage box permits viewing of the object inside without having to open the box. An electrochemical cell is created where the metals act as anodes and cathodes in the presence of an electrolyte (water with salt). For example, acidic paper noticeably degrades at room temperature within a few decades, becoming yellower and much more brittle and fragile with age. For long-term use of foams, such as for object storage mounts, it is best to use only new foam. Figure 25. Plastic storage bins are usually made of polyethylene and available at a good price. However, it is not recommended they be in contact with an object over the long term due to concerns over the release of chloride. Technical Bulletin 14. Sheets of acid-free buffered or unbuffered paper are useful as a light covering material over objects, as thin interleaves or as a wrapping layer. a wooden sculpture on a wooden base), there will usually be no significant damage observed over time. Consult Test #2: pH test using glycerol to measure the acidity of volatile compounds for a description of this test. The products are grouped alphabetically according to function and material. Thus, gaskets made with this type of rubber are generally inappropriate in a museum setting.