Volume 4, Number 1, Feb. 1982, pp.3-4

Technical Exchange

Zonarez #7085

In January, 1981 we bought five pounds of Zonarez #7085, polyterpene resin (Lot #BX2001). We used a small amount for some tests and placed the rest (in its original container) in a storage house. The storage conditions, although not humidity and temperature controlled, were not at all extreme and there was no exposure to strong light. Approximately six months later we opened the container and discovered the Zonarez to be extremely discolored. The resin had deepened to a tone something near that associated with colophony.

We have not tested the properties of the aged Zonarez to see how they have changed. If anyone else has made a similar observation, we would appreciate hearing from them.

Bubblewrap and Silver Objects

A problem has come to my attention regarding the packing of silver objects for shipping or storage, indicating that plastic bubblewrap, such as AirCap, a common museum packing material, encourages tarnish-clouding of silver surfaces with which it has direct contact.

The San Diego Museum of Art recently found it necessary to pack and move a large number of its silver acquisitions to temporary storage in another museum. Although the writer had recommended to the Museum's Registrar that he preferred the silver to be wrapped in soft cloth prior to packing (fearing possible scratching of the surfaces by electrostatically attracted dust), it was decided to pack the items directly in new, clean AirCap. The Registrar had called the local AirCap distributor and had been informed that the product contained no harmful tarnishing agents. This information was evidently incorrect, for when, after three weeks, the silver came home and was unpacked, it was discovered that the majority of items had acquired an uneven clouding of tarnish, apparently from contact with the AirCap.

Two forms of tarnish were noted. The first was an even clouding with a mild orange color, found on items that had been wrapped with the smooth layer of the AirCap next to the silver surfaces. The second form was a heavier layer of tarnishing with clean voids where the bubble surfaces had pressed against the silver. In both instances the areas of clouding were not uniform over the objects. Clouding mostly occurred in bands or cloud shapes of no more than a few inches dimension, particularly over rims and lips of vessels and their lids, and on the swelling sides of pear- shaped pieces. Although light in appearance, the tarnish is quite recalcitrant, and will not wipe away with a clean cloth, requiring, instead, the use of a silver polish.

Although this danger may be known to others, it was a surprise to us, and a reminder that even manufacturers' distributors may not have the best information regarding the properties of their products

The San Diego Museum of Art has noticed that plastic bubblewrap used for storage and shipping of silver causes tarnish-clouding on the surface. The Los Angeles County Museum of Art has also made this observation. The problem was looked into by the LACMA Conservation Department. The plastic bubble is made from polyethylene film which is then coated with a liquid saran so that the air does not leak from the vacuum drawn fresh (Los Angeles) air bubbles. It is therefore concluded that it is the saran which causes the problem in close proximity to the silver for long periods of time. Neither bubble-pack nor saran should be used for storing silver. It is recommended that silver be stored in polyethylene plastic, "ZipLock Bags" (a high quality food grade plastic) or in the more expensive cloth silver storage bags.

Stretcher Bars and Museum Expansion Bars

The Bay Area Art Conservation Guild (BAACG) held a very interesting and productive discussion and working session with several of the area's foremost makers of stretcher bars and museum expansion bars on January 19, 1982. Names of the makers and details about the various stretcher bars will be published in the next BAACG newsletter. For further information, write to: Elizabeth Cornu, Conservation Department, Fine Arts Museum of San Francisco, CA 94118.

Redding Museum & Art Center

The Redding Museum & Art Center offers conservation and consultation services in the area of ethnographic and historical artifacts, most notably Native American Basketry. The Museum is equipped with a methyl bromide fumigation chamber and is willing to travel to inspect collections and prepare condition reports on collections. A brochure fully describing services and fees is available from:

Redding Museum & Art Center
P.O. Box 427, Redding, CA 96001

Animated Cel Restoration

With increasing frequency, we at the Los Angeles County Museum of Art have been receiving inquiries from the public concerning the restoration of animated motion picture film cels. Referrals and/or technical information is available from Ron Stark, Vice President, International Animated Film Society. Telephone number is (213) 466-0341. The Film Society's restoration efforts, however, do not extend to animated films themselves.

Leaf Casting

The Western Regional Paper Conservation Laboratory, under the direction of Bob Futernick, is developing a new method for leaf casting on the vacuum suction table. A presentation of this method will be made in Milwaukee, Wisconsin, at the Annual AIC Conference.

Conservation Framing

Framespace (see illustration) is marketed as an interior spacer for the conservation framing of works of art on paper. The manufacturer, Frame Tek, is concerned about the long term stability of the plastic used, Kodar copolyester. With this concern, Frame Tek enlisted the services of Failure Analysis Associates in Palo Alto, California and Ultrachem Corporation of Walnut Creek, California to determine if any organic or inorganic thermal decomposition products could be observed while a specimen of the plastic was held at 100 C. None were observed. A copy of the letter from Failure Analysis Associates is on file at the Los Angeles County Museum of Art, Conservation Center. Contact V. Blyth Hill or J. Druzik.

Inquiries about Framespace can be made directly to them.

Frame Tek
2134 Old Middlefield, Mountain View, CA 94043 (415) 964-7137

Stolen

On November 6, 1981, The Bindery, 7513 Melrose Ave., Los Angeles, California 90046, (213) 653-0071, was burglarized!! by person or persons unknown. The nature of the crime indicates that the thieves knew exactly what to steal to set up a hand bindery and were apparently familiar with the location of those items within The Bindery itself. They would also have had to be strong and to have had a van or truck as the items stolen totalled some 750 pounds. Naturally they have suspects in mind and are proceeding with a full investigation both by the Los Angeles Police Department and by private investigators.

A list of the missing items is available from The Bindery at the address and telephone number listed above from Frank Buxton and Charles Collings. They ask you, please, to be alert for any sign of items being offered for sale or actually being used by a bookbinder, perhaps someone who has recently started a bindery. They can identify everything!