Difference between revisions of "Rehousing Materials"

Revision as of 04:42, 15 June 2020

Statement of Purpose

This list of materials is primarily drawn from Chapter 29: Support & Rehousing for Collection Storage of the Preventive Conservation: Collection Storage volume. This page provides information on materials commonly used by preservation professionals for constructing safe storage mounts divided into broad categories:

• Boards and papers
• Foams, padding and support material
• Film and sheet products
• Fabric and soft products
• Adhesives
• Tapes
• Mechanical fasteners
• Sewing
• Products for metal storage

Also listed below are materials that are deemed inappropriate for long-term storage. Items are listed by trade name and when possible manufacturer information is included. It is important to do due diligence before purchasing materials to ensure that they are, in fact, made from inert or preservation quality materials (see Collection Storage chapter by Hatchfield). When possible, purchase conservation-tested storage supplies from a reputable archival supplier. A list of some commonly used suppliers is available on the American Institute for Conservation's wiki site.

Contributors

Rachael Perkins Arenstein, A.M. Art Conservation, LLC; Lisa Goldberg, Goldberg Preservation Services; Eugenie Milroy, A.M. Art Conservation, LLC.

Boards and Papers

Bristol Board - This type of heavy, high quality double-sided paper was originally produced in Bristol, England and is currently available in various plies. It may be used for interleafing, dividers and supports. The surface texture varies from smooth to vellum to rough finish. Paper board with this name is not always archival quality. When using this product, take care to choose pH neutral, lignin-free varieties.

Corrugated Board - Also known as blueboard, this light blue-gray colored, acid-free, lignin-free board is buffered against acid migration. A water resistant, modified starch adhesive of neutral pH is used for corrugating. The panels are fabricated in single wall, double wall, and cross-laminated double wall construction and in thicknesses from 1/16” to 1/8”. Fluting size (designated by a letter, generally A-F) refers to the number of folds per foot. B-flute and E-flute styles are commonly used.

Coroplast - The original brand name for corrugated polypropylene sheet. This material is a rigid, lightweight, polypropylene/polyethylene copolymer. Always purchase from an archival supplier as versions with coatings and additives are widely distributed. This material may be cut or scored with a utility knife and bent with heat. Sheets are available in several thicknesses, 2-6 mm.
Foam Core - Refers to a laminated panel composed of at least one lamina of expanded polystyrene and at least one other lamina, such as, paper, metal foil or plastic film in thicknesses of 1/8", 3/16" and 1/2". There are both archival and non-archival products available (many sold as Foam Core). Avoid using cores of beaded Styrofoam, as the beads can easily break apart at the edges. There is some evidence for off-gassing of formadehyde from these produces, so careful selection and choice of material is critical.

Glassine - This is a thin and translucent paper with a very brittle handle and smooth surface created by calendaring. Glassine is used for interleaving, envelope enclosures, sheet support and draping. The material is made by a number of manufacturers and is available in pre-cut pages, envelope enclosures or roll form. Dyed versions should be avoided.

Mat Board - This term can refer to a wide variety of material and the differences in quality vary widely. Standard mat board may be wood pulp and acid-neutralized and inappropriate for use with collections. Rag mat board is a step up with a cotton core and backing and acid-neutralized facing. The best option for safe storage is 100% cotton mat board sometimes known as Museum Rag. Mat board is available in a variety of colors and thicknesses (e.g. 4-ply and 8-ply).

Tissue Paper - Tissue paper is commonly used in sheet form, and as a wrapping or draping material. Varieties of tissue abound and only acid-free papers should be used for storage. Acid-free tissue paper comes in various weights (or thicknesses), designated by the paper “pound”; 12 lb. and 18 lb. are most common). Tissue is either unbuffered or buffered. Buffered tissue is pre-loaded with an alkaline reserve and is only used for very specific purposes (See National Park Service Conserve O Gram 4/9 for a table on uses of buffered v. unbuffered tissue). Tissue paper also comes in long fibered varieties made from different plant products, such as Abaca paper, or Japanese tissue papers (a class of tissues made from a variety of plant products) that are more commonly used for conservation treatment and restoration projects. Using tissue paper to enclose or stuff individual items is generally not recommended because these methods usually involve extra handling for collection items.

Foams, Padding and Support Materials

Ethafoam® - This brand of polyethylene foam is heat finished to provide a smooth upper and lower surface. It is available in both plank and sheet form in a variety of thicknesses and densities as ranked for vibration and shock absorption and these are given different numerical designations. Plank foam #220 and sheet #221 are the most commonly used densities. Ethafoam can be shaped in a variety of ways, using knives (electric and variously shaped blades) and hot melt adhesive. When manufactured in flexible sheet form, plasticizers and surface modifiers have been applied to give it the flexibility and finish that is required for its commercial use. Ethafoam may be susceptible to UV degradation over time. Manufacturer - Dow Chemical Company.

Backer Rod - Backer rod is round, flexible continuous lengths of extruded closed cell polyethylene foam with a closed-cell outer skin and a highly resilient interior network of open and closed cells. Polyurethane varieties of backer rod are not appropriate for collections storage. Manufacturer - Nomaco, Inc.

Honeycomb Aluminum Panel - These lightweight panels of high strength are sometimes constructed from composite materials. Their properties can be modified through choice of cell size and height. Resistant to corrosion and moisture, they can be used for a wide variety of storage mount applications.

Minicel® - Cross-linked polyethylene foam has a smooth surface that will not abrade objects. This brand is available in various dimensions. Manufacturer - Voltek.

Trapezoidal Backer Rod/Timber Grip - This closed cell (polyethylene) foam has an isosceles trapezoidal profile. Its shape and flexibility make it useful for mount making and artifact support as well as for forming dividers in boxes and drawers. Sold in 4 foot lengths in widths from ¾” to 5”.

Volara - Volara is a smooth-surfaced closed cell polyethylene foam. It comes in 1/8”, ¼” and ½” thicknesses and has many storage and support applications. Manufacturer - Voltek.

Film and Sheet Products

Marvelseal® - This barrier film is composed of laminated nylon, aluminum and polyethylene. Marvelseal is an effective vapor barrier against the transmission of water vapor and atmospheric pollutants. Its applications include passive humidity control in storage and lining to decrease off-gassing from exposed wooden surfaces of shelves or crates, and it can also be used to create a sealed package. It bonds to itself, so a heat sealer can be used to create custom enclosures with an air-tight seal. Different versions are available - Marvelseal 360 is the most commonly used in conservation. Marvelseal 470 is more easily heat-sealed but less resistant to puncture than the M360.

Mylar/Melinex - This polyester (polyethylene terephthalate) film is used to create a variety of enclosure types and is commonly used with within libraries and archives. For example, Melinex Type 516 or Mylar D brand can be used for wrapping rolled textiles. Mylar can also be purchased with a silicon release coating for use in special applications. Manufacturer - DuPont.

Tyvek® - Tyvek is a non-woven, spunbonded olefin sheet made from high-density polyethylene fibers, available in a variety of thicknesses and surface patterns, sheet and rolls and different weights. While this is the same material as “home wrap”, the printed fabric should not be used in storage applications. Tyvek sheet may be utilized for linings, pillows, garments, lifting sheets, rolling textiles and custom trays for fragile items. Tyvek covers can protect cultural materials from dust while allowing for air circulation. “Soft” drapeable Tyvek® style 1443R can be washed in the washing machine and seamed for supports. “Hard” Tyvek® or 1025D can be used to create smooth covers, support slings, interleaving and wrappers. Manufacturer - DuPont.

Polyethylene Self-Closing Bags – Zip-top style bags can be convenient for storing fragments and are available in various sizes. Care must be taken to choose “archival” quality polyethylene because varieties used for everyday activities such as food storage may contain plasticizers and additives that will deteriorate over time.

Fabrics and Soft Products

Fabrics and soft products have wide application in collections storage for lining, wrapping, stuffing, tying and strapping.

Batting - 100% polyester for internal pillows to create soft supports as needed. Only heat bonded polyester batting is recommended, as resin bonded batting may include adhesives that can off-gas or finishing agents that can attract pests. Polyester batting is available in various thicknesses and lofts. Dense polyester felts have different functions and purposes than fluffy polyester batting when constructing storage supports. Polyester fibers are very abrasive, so it is always covered with a fabric or non-woven layer to separate it from the surface of collection items.

Buckram – Generally refers to a plain-weave cotton (although sometimes linen) fabric stiffened with an aqueous-based starch or glue sizing (pyroxylin stiffened fabrics are not appropriate and have generally been replaced by acrylic coatings as an alternative to starch based sizing). The material can be moistened, molded to shape and dries creating a stiff support. Buckram comes in a variety of colors and is used in bookbinding, library enclosures and textile supports.

Cerex® - Cerex is a spunbonded type 6,6 nylon fabric, Manufacturer - Cerex Advanced Fabrics, Inc.

Cotton Interlock Knit - 100% cotton weave fabric that can be stretched to create a smooth three dimensional covering for a support surface.

Fosshape® - A nonwoven, proprietary 100% polyester polymer blend with no additives or post treatments is available in two weights, 300 and 600 and is generally white in color. The felt-like fabric is activated by dry or steam heat (in the range of 100-130˚C or 212-265˚ F), causing the fibers to soften and contract. The material becomes rigid on cooling. Mounts made from fosshape must take into account the considerable shrinkage that occurs on cooling. Fosshape is used to construct mannequins and supports especially for textile and costume collections. Extensive information is available on the AIC wiki site. Manufacturer – Wonderflex World.

Hollytex - Hollytex #3529 is a non-woven polyester fabric. Manufacturer - Ahlstron Filtration Inc.

Muslin - 100% cotton muslin (plain weave, lightweight), is used as a covering and for internal supports/pillows for various items, rolling textiles, lining mounts, exhibit forms or mannequins.

Reemay® - Reemay is a spunbonded, polyester fabric Manufacturer - DuPont.

Stabiltex - Stabiltex No. 4. is a sheer, plain weave 100% polyester multifilament fabric, heat set and unfinished. Other types of Stabilitex have a gauze weave and heat set finish. Manufacturer - Swiss Silk Bolting Cloth Manufacturing Company, Ltd., Zurich.

Stockinette - 100% cotton (unbleached) or 100% polyester knit tubular fabric (orthopedic stockinet) is used for internal supports/pillows for various artifacts, exhibit forms and mannequins.

Twill Tape - 100% cotton (bleached or natural) for tying and strapping available in assorted widths - ½ to 1” are useful.

Tyvek® - (See Film and Sheet Material above). Note here that Tyvek comes in a smooth surfaced sheet material and a soft drape fabric that can be used for purposes where shaping is crucial. The “handle” of soft pack Tyvek (1443R) changes when it is machine washed and it takes on the properties of a fabric. Manufacturer - DuPont.

Adhesives

These are some of the adhesives commonly used in creating supports and containers.

Hot Melt Glue Sticks - Hot glue refers to thermoplastic adhesive applied in the molten state and forms a solid when cooled. Many formulations are available from several major companies. Evaluating the adhesive components and melting temperature in the stick formulation is crucial in determining the long term stability and adhesive properties of the material. Note that melting temperature can affect working properties and protocols, creating wide variation in how the glue is used. Ethylene vinyl acetate polymer (EVA) has been found to be safe for storage mounts. Some specific formulations of adhesives comprised of EVA are - 3M Jet Melt™ Glue Sticks No. 3764, Evo-Stik® 7702, Thermogrip® 6363, Maxistick 6300 Hot Melt Glue Stick. Note that low temperature hot melt glue (3M #3792 LMQ) is used for paperboard and foam, and high temperature hot melt glue - (3M # 3748Q) is used for Coroplast.

Emulsion Adhesives - Polyvinyl adhesives (PVA), not known for their long-term stability, yet conservation grade versions of these adhesives are commonly used for gluing and hinging paper board products. Care should be chosen in selecting an appropriate PVA emulsion.

Wheat Starch Paste and Methyl Cellulose - Commonly used as adhesives by conservators and preparators, these materials are purchased dry and are cooked or mixed to appropriate consistencies for use in hinging, gluing and adhering paper based products.

Tapes

Pressure Sensitive Adhesive Tapes - The composition of the carrier (film or fabric) and the adhesive are critical in choosing a tape for joining two things together. Note that this category includes double sided tapes. Some materials of choice include linen backed bookbinder’s tape and double-sided tape (3M #415).

J-LAR - J-lar is a clear pressure sensitive tape with a polypropylene carrier and a methacrylate adhesive. Manufacturer - Permacel.

Filmoplast® – There are several lines of Filmoplast tapes using either clear tissue or white paper carriers and a pH-neutral to alkaline, non-yellowing, water-based acrylic dispersion adhesive. While some are advertised as appropriate for use on artwork or archival items, others are more suitable for constructing enclosures. Manufacturer – Neschen AG.

Teflon® - Teflon tape is a polytetrafluoroethylene (PTFE) fluorocarbon polymer. It is available as plumber's tape at the hardware store and in wider widths as 8” Teflon® Relic Wrap™ Film has an extremely smooth surface. Manufacturer - DuPont.

Mechanical Fasteners

Mechanical fasteners can be used instead of or to reinforce adhesive joins in the construction of storage mounts.

Magnets - Ferrous magnets of varying strength can be useful in storage and support applications. Detailed information is available on the AIC wiki site.

Monel Staples - These marine grade staples for use in a staple gun are made from a copper/nickel alloy and are highly corrosion resistant. They come in heavy and light duty varieties. Manufacturer - Arrow Fastener.

Nylon Rivets - Two part (male and female) nylon mini ratcheting action rivets can be used to secure box or tray corners and reinforce glued attachments. These are particularly well suited to use with Coroplast board. Manufacturer - Micro Plastics Inc.

Pins - Nylon head, non-corrosive insect pins.

Velcro® - The original brand name for nylon hook and loop fastening tape. Velcro products can be purchased with or without an adhesive backing, in lengths or pre-cut shapes. The non-adhesive backed product must be sewn or glued to a substrate, such as a heavier weight fabric or board, which is then attached to the substrate. Velcro purchased with a pressure sensitive adhesive backing must be chosen with care; the adhesive should be ph neutral and may fail over time.

Sewing

Cotton thread - Undyed is preferable Manufacturer - DMC cotton thread, Gutterman or Mettler.

Dental Floss - Nylon or Teflon floss can be used for long-term storage but it can be cutting and a wider Teflon tape may be preferable. Cotton floss is often waxed and is therefore not a good choice for storage.

Products for Metals Storage

Corrosion Intercept® (CI) bags - Semi-conductor technology transforms these plastic bags into a protective reactive barrier against corrosive gases, fungus and bacteria. Copper particles are bonded to a polymer matrix, forming a reactive film. This material is suitable for storage of non-ferrous metals such as gold, silver, platinum, aluminum, tin, copper, zinc, and brass. The bags can be purchased with built-in saturation indicator and in smaller sizes with one clear side so stored items are visible. Zip-top bags are available or bags may be sealed with a heat sealer. Manufacturer - Engineered Materials Inc.

Pacific Silvercloth® - Brown colored, cotton flannel cloth with embedded silver particles trap pollutants that tarnish silver. Similar products embedded with zinc or other metals have not proven to be as effective. Cloth that may be used to make bags and line trays for storage of silver and silver alloys. Manufacturer – Pacific Silvercloth

Inappropriate Materials

The following materials are generally deemed inappropriate for long-term storage as they may degrade and cause damage through structural failure, decomposition or off-gassing.

• Non-archival cardboard and fiberboards
• Non-archival tissue papers
• Cotton wool
• Felt
• Non-color fast dyed fabric
• Polyester batting that is bonded with adhesives
• Poly vinyl chloride (PVC)/vinyl products
• Polyurethane foams
• Plastic sheeting or bags that is not “archival” grade polyethylene
• Bubble wrap