Volume 4, Number 2, May 1982, pp.3-4

Technical Exchange

Pigments

Add this source to your WAAC Resource file cards: Daniel Smith, Inc. has a wide variety of pigments available--many at prices 20% off list including Windsor Newton watercolors and gouaches, dry pigments (prices especially good in bulk), egg tempera, Shiva casein, etc. They offer other supplies as well as ship orders promptly via U.P.S. Write for complete catalog, 1111 West Nickerson Street, Seattle, WA 98119 or phone (206) 282-4329.

Conservation of an 18th Century Valence from Prague

A valance from the Hebrew Union College Skirball Museum is currently on loan to the Los Angeles County Museum of Art for their textile exhibition "600 Years of Embroidery from the Permanent Collection." The valance was conserved by Janet Davenzer, Textile Conservator, in the Lazareck Textile Laboratory of the Hebrew Union College Skirball Museum.

The silk damask valance dated 1724 is heavily embellished with metallic embroidery. It was soiled with brittle areas in the damask and oxidized metallic threads (see photos) <graphic status=omitted>. Briefly, the treatment involved wet cleaning, mending, use of jeweler's fiberglass brush on metallic thread, the replacement of linen linings (saving the extremely worn originals) and attaching a muslin backing with Velcro for exhibition.

This valance is a fine example of metallic embroidery work of the 18th century from Prague, made to hang above the Ark in a synagogue.

Large Aluminum Honeycomb Panels for Lining and Consolidation of Oversized Paintings

The normal maximum dimensions of readily obtainable aluminum supports is usually 48" x 96". If a larger support surface is required for an extremely large painting then the problems of fabricating a support to required dimensions becomes a crucial consideration. Most manufacturers of lightweight honeycomb supports employ a number of techniques to join pieces to create dimensions larger than 48" x 96". Simple joining and splicing techniques range from butt splicing to more elaborate internal box joints. Whatever technique is employed provisions for assuring joint strength under deflection and adequate rigidity must be noted that not all manufacturers of honeycomb material have adequate experience or familiarity with use of these materials for conservation purposes. Construction practices that seem adequate for certain industrial applications can be seriously inadequate when used in conjunction with conservation needs.

As previously mentioned, construction of joints or seams in oversized panels is a critical area. In considering the joining of two pieces of honeycomb material to make a larger panel two aspects of construction are exceedingly important:

1. The employment of a joining technique that will prevent any deflections in the area of the seam. This usually implies using a box joint.
2. The use of a suitable adhesive to insure adequate strength under conditions to which the panel will be subjected. Since most panels are heated in order to use a wax/resin lining adhesive a high temperature epoxy adhesive is usually used.

The most detailed evaluation of aluminum panel construction can be found in an article by Marion Mecklenberg and Judith Webster, "Studies in Conservation," 22 (1977) p. 177-189. Although it is possible for conservators to construct oversized aluminum honeycomb panels themselves this is not always practical due to work space considerations, difficulty in obtaining the proper type and quantity of adhesive, and the difficulty in storing adequate supplies of aluminum skin to minimize waste as well as the fragile nature of the aluminum core material. Since it is unlikely a conservator will have a frequent need for oversized panels the main value of this article is to become familiar enough with panel construction to be able to direct a manufacturer to construct a panel to given specifications regarding join construction and adhesive type. Also useful are the numerous technical pamphlets available from the Hexcel Corporation which discuss properties of construction and adhesive selection.