CHOOSING AN ADHESIVE FOR EXTERIOR WOODWORK THROUGH MECHANICAL TESTING

Abstract

Through mechanical testing, an appropriate adhesive was found for reuniting the fragments of exterior wooden capitals. The adhesive needed to have superior weather resistance, flexibility, gap-filling capability, reversibility, longevity, and workability. From four different adhesive classes, a candidate adhesive was chosen for testing: Butvar B98 with granulated cork, ConServ Flexible Epoxy Patch 200, 3M Marine Adhesive Sealant 5200, DAP Dynaflex 230, and Dow Corning 738 Silicone Rubber with microballoons. The test program included cyclical tensile and compression tests, a uniaxial tensile test, and accelerated weathering. The Epoxy proved to be the most brittle, Butvar showed fatigue until failure, while 3M had excellent properties such as a low elastic modulus (high ductility), (visco)elastic behavior, and longevity. Both DAP and Dow Corning developed fissures in the paint prematurely and were eliminated from extensive cycling tests.

Keywords:

• Adhesive
• Cyclical tensile and compression test
• Uniaxial tensile test
• Weathering
• Architectural
• Exterior woodwork
• Conservation
• 3M 5200
• Butvar B98
• Silicone rubber
• DAP
• Epoxy
• Cork
• Gap-filling
• Flexible

Sources of Materials

3M Marine Adhesive Sealant 5200 3M Center Building 223-6S-06 St. Paul, MN 55144-1000 Butvar B98 Conservation Materials Ltd. 1275 Kleppe Lane, #10 PO Box 2884 Sparks, NV 89431

Conserv Flexible Epoxy Patch 200 Housecraft Associates 7 Goodale Rd Newton, NJ 07860

DAP Dynaflex 230 DAP Inc. 2400 Boston Street Baltimore, MD 21224

Dow Corning 738 RTV Dow Corning Corporation South Saginaw Road Midland, MI 48686

Granulated cork Jelinek Cork Group 4500 Wier Industrial Estates PMB 167 Niagara Falls, NY 14305

Old Village Exterior Primer 1236 white Old Village Exterior Paint M26727 (Alkyd) Old Village Paint 400 Stenton Ave Plymouth Meeting, PA 19462

Phenolic Microballoons Asia Pacific Microspheres SDN BHD NO 9 Jalan Utas 15/7 40200 Shah Alam, Selangor Darul Ehsan, Malaysia

Notes

1 Philadelphia Museum of Art, Historic Houses, http://www.philamuseum.org/historichouses (accessed October 13, 2014)

2 According to the BBC Weather Centre, http://www.bbc.com/weather/4560349 (accessed April 10, 2014)

3 According to the BBC Weather Centre, http://www.bbc.com/weather/4560349 (accessed April 10, 2014)

Additional information

Notes on contributors

Rian M. H. Deurenberg-Wilkinson

Rian M. H. Deurenberg-Wilkinson is Conservator at Fallon & Wilkinson, LLC, a private conservation firm in Connecticut. She held a 2-year position in the Sherman Fairchild Center for Objects Conservation at the Metropolitan Museum of Art in New York, after concluding a 3-year Andrew W. Mellon Fellowship at the Philadelphia Museum of Art, during which she conducted this research. She graduated from the furniture conservation program at the Netherlands Institute for Cultural Heritage (ICN) in 2001 and has worked in private and institutional conservation labs in both the Netherlands and the United States. Address: 32 Bushnell Hollow Road, Baltic, CT 06330. Email: [email protected].