Volume 13, Number 1, Jan. 1991, pp.24-25

Technical Exchange

Left Gauge for Board Shear

I had a custom made left gauge made for my Vagelli board shears several years ago because of the problems encountered with the gauge which came with the cutter: excessive weight; scratching of the surface of the table causing materials to pick up the green paint residue; and generally clumsiness.

The new gauge is made of a lightweight aluminum, with teflon skids on the bottom providing a very smooth action. It is anodized so there is no transfer of oxides to the operator or to material being cut. We have since made them for two other cutters in the book repair unit, a Jacques shear and an older cutter, both of which required the machining of new "guides" for the gauge to travel on.

I am now offering them for sale to any interested parties who would like to replace their Vagelli left gauge. If there is more interest, I can have them made for other cutters on a custom basis. The cost will be $200 for the Vagelli model.

We have been extremely pleased with these gauges, because their light weight and virtually frictionless movement provide for very quick and easy adjustment.

Send your queries to me here or call me at 801/378-7654.

Aid for Cross Section Preparation

For those of you who are as tired as I am of sanding bits of your fingers bloody when you are preparing cross sections, I have a simple and cheap alternative to the usual holders, based on dop sticks used in lapidary to hold stones while cutting them. It can be made in ten minutes with a wooden dowel, some Akemi Marmorkitt Super (the thick version of the methacrylate marble filler) and a piece of mylar.

Figure 1.

Mix up a small amount of the Akemi and, on a flat surface, form into a mound on a piece of mylar. Cut a piece of the dowel about 3 inches long and place it upright in the Akemi so that is just above the mylar. Using a spatula, pull the Akemi up along the sides of the dowel as in the illustration below (Fig. 1).

After the Akemi has set, grind or file off the excess.

Figure 2.

To use this holder, sand your sample cube flat on one side and glue it to the flat side of the holder (Fig. 2) with cyanoacrylate adhesive. After polishing the sample as usual, grasp the sample firmly in a vise and push on the stick. Since the cyanoacrylate adhesive doesn't have much shear strength, the stick should come off easily. The stick can be reused by giving it a light sanding to remove the excess glue before adhering a new sample.

Fabric Paints for Compensation

When it comes to costume and textile reconstruction, textile conservators are occasionally confronted with large areas of loss. Most often these areas of loss are compensated for by inserting a compatible fabric patch, usually of a solid color. Problems arise when the area of loss disrupts the visual impact of the artifact leading the owner or curator to request that the missing design motifs be inserted. A variety of techniques have been explored with varying degrees of success, including pencils and crayons, paints, silkscreen, photo-reproduction and embroidery. It must be remembered that these techniques are applied to a modem patch, never to a valuable artifact.

During the past year, Teresa Knutson, LACMA's Mellon Fellow in Textile Conservation, has been involved in the reconstruction of a 17th century Italian court dress. Upon determining the final form, it was found that several large areas of embroidery were missing. Modern fabric was dyed to match the original and inserted between the original fragments to compensate for the loss.

Cara Varnell has been assisting Teresa with the final phases of the reconstruction and she has been working with the Lumiere and Neopaque Fabric Paints to compensate for the losses in the embroidery. These paints are popular with fabric artists and theater costume designers but, of course, conservators greet most new products with skepticism. Material Safety Data Sheets indicate that this latex paint is sold as a viscous liquid, dispersible in water. The experiments at LACMA indicate that, when applied according to directions, the paints are quite permanent. We tried to dissolve the paints in common organic solvents and also scrubbed them with detergent and water. We found that the paints, which remained very flexible, did not dissolve, flake, rub off, or crack. With these encouraging results, the paints are being used to re-create the lost embroidery in the areas where modern fabric patches have been inserted.

Lumiere and Neopaque Fabric Paints are available exclusively from:

Cerulean Blue (Color for the Fiber Arts)
P.O. Box 21168
Seattle, WA 98111-3168
206/443-7744

A catalogue costs $4.50

We would like very much to hear from anyone else who has had experience with compensating for loss with fabric paints. We also welcome comments regarding ethical and aesthetic concerns.

Survey on Ethnographic Binding Media

The Ethnographic Working Group of ICOM has devised a plan to create a "library" of the binding materials used in ethnographic paints.

As a first step, a questionnaire is being distributed as broadly as possible to discover more about existing sources of information. Respondents are urged to reply to the questionnaire whether or not they are able to identify resources; the surveyors are also interested in learning just how much people don't know. The following is just a sample, to give you a sense of questionnaire's intent:

Could you name Museums/Universities/Arboretums/Herbaria that have binding media collections?

Do you know of objects with known date and provenance, in collections, that have been well documented with reference to the binders used in them?

Which anthropologists have undertaken well documented studies on binders and in what area(s) of the world did they work?

Do you know of any anthropologists who are presently making field collections?

For a full questionnaire or further information: Leslie Bone

Ethnographic Binding Media Project
Conservation Department
M. H. de Young Museum
Golden Gate Park San Francisco, CA 94118

3-D Digitizing System

In the October issue of Byte, a new digitizing system for the IBM PC is described. Using high frequency sound waves, the Pixsys Series 300 sonic digitizer maps 3-dimensional coordinates of real-world objects and can be used to record not only physical form, but changes in location. Intended for applications in robotics, animation and aerospace design, etc., the Series 300 can record up to 16 points simultaneously at 60 points per second.

The unit works by bouncing high frequency sound waves off an object into an 44 square inch array of microphones. The signals are then processed through a multiplexer box to the serial or parallel ports of a microcomputer where they can provide input to the system's coordinate acquisition software. There are also optional programs for 3-Dimensional CAD/CAM and motion tracking.

Although the system's price ($12,315 plus another $1-$4000 for the optional software) puts it out of the reach of most of us, when prices come down this tool could provide an effective means of recording and monitoring changes in the morphological and structural characteristics of complex objects.

Pixsys
1727 Conestoga Street
Boulder, CO 80301 303/447-0248

Earthquake Drill

The Asian Art Museum and Fine Arts Museums of San Francisco conducted an Earthquake Drill in November which was observed by museum professionals from other institutions. This was conducted after an intense staff effort was made to write a new Emergency Response Procedure. While a laborious and painful process, it is one we would highly recommend to all institutions for the long term preservation of staff and collections. If your institution needs to begin to act in this direction, we would gladly refer you to our Facilities Manager, who wrote and coordinated most of the effort.