Volume 6, Number 3, Sept. 1984, pp.14-15

Technical Exchange

Various authors

New Information on Glycol Ethers

Glycol Ethers, the family of solvents that includes Cellosolve and Cellosolve Acetate (Ethylene Glycol Monoethyl Ether or 2- Ethoxyethanol and 2-Ethyoxyethyl Acetate) have been found to be far more hazardous to health than previously thought. Without knowing everything about the studies, it seems that recent test results have demonstrated effects (birth defects) to pregnant test animals and hematological effects (changes in blood chemistry) to animals.

While none of these effects have been noted in humans, it is being recommended that the ACGIH (American Conference of Governmental Industrial Hygienists) adopt a 3 ppm (3 parts per million exposure over eight hours) exposure limit for Cellosolve. The current TLV (threshold limit value) is 100 ppm for skin exposure. CALOSHA (the State of California Occupational Safety and Health Administration, 415-540-3037) has offered two half day seminars on "Occupational Exposures to Glycol Ethers" discussing:

Cellosolve and Cellosolve Acetate are used in conservation. The paint and varnish industry uses these agents as drying inhibitors. At the Los Angeles County Museum of Art the paintings conservation department is now planning to reformulate its varnish mixtures, eliminating Cellosolve in current recipes. Cellosolve will still be used when absolutely necessary, but with increased care to avoid exposure.

Chris Stavroudis, Los Angeles County Museum of Art

Equipment Leasing

Recently Thorne Leasing has been in contact with conservators on the west coast who have expressed interest in leasing equipment important to the treatment of fine works of art. Vacuum hot tables, vacuum suction tables, polarizing microscopes, stereo binocular microscopes, solvent evacuation systems (for evaporation), non-destructive analytical instrumentation and photographic equipment can all be leased to preserve valuable working capitol.

Contact: Lawrence Krueger at (213) 947-8742 for new equipment, laboratory upgrades and renovations.

Lawrence Krueger, Thorne Leasing

Expanding Stretchers for Large Paintings

A new expanding stretcher system for large paintings which utilizes a complex engineered aluminum extrusion is presently in production and is expected to be available in October 1984. The system has been designed by a conservator for the needs of conservators and features adjustable axial spring-loaded tensioning, expansion capability of one inch per corner in each direction, a floating tacking edge that allows both side and back tacking using existing tacking edges of the canvas and standard fastening with staples or tacks, and supported corners to prevent crushing the canvas when the stretcher is expanded. The system uses an innovative fold design that needs no tube or anything else in contact with the face of the painting if it requires a folding stretcher.

The system was designed over four years to fulfill the dynamic requirements of stretching a canvas painting and does not have the usual shortcuts and compromises that make other systems ineffective. It is expected that central sag from differential stretch of the body of the canvas and the edges will be eliminated. Pricing will be competitive with custom-built wood stretchers.

Distribution will be handled by InTAC - Innovative Technology for Art Conservation, 7000 Stockton Ave., El Cerrito, CA 94530 (415)524-9500. InTAC anticipates introduction of other specialized products in the future and will also handle custom development on a single job basis.

Arsenic Testing

An article in the RMRCC's Spring 1934 newsletter discussed the presence of arsenic in certain museum specimens. The RMRCC received a letter from A&L Agricultural Laboratories, Inc. in Memphis offering analysis for arsenic at $20 per sample. A discount is available for quantities of samples. A gram sample is required for detection of quantities over 1 part per million. The sample can be taken from the underside of a specimen in an inconspicuous location.

If interested, contact Mr. Dan Moffet, Laboratory Manager, A&L Laboratories Inc. 411 North 3rd Street, Memphis, Tenn. 38105- 2723.

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