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Saturday, May 31 • 2:30pm - 3:00pm
(Architecture Session) Comparative Study of Commercially Available Rust Converters

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NCPTT’s Materials Research Program’s current research project is a continuing comparative study of rust converters. Rust converters have wide stretching usage in conservation, they are used from the stabilization of iron based museum artifacts and collections to iron architectural elements and iron outdoor sculpture.

Rust converters are designed to be only a single part of an overall coatings system. However, for this study it was decided to only test the converter by itself. This decision was made for two reasons; the first is many museums use the converter as a single coating, especially for outdoor farm and military equipment. The second reason is to evaluate the strength of the converters themselves without the added protection of a paint system.

For this study we used naturally weathered mild steel coupons cut with a mechanical sheer (as to not alter the surface of the metal) to 3”x6” the size of the QUV sample holders. Each of the front face of the plates was wire brushed to remove loose rust them treated with a rust converter, tested weathered and tested again. The products were evaluated and ranked by rate of failure.

The samples were evaluated by a variety of techniques before being treated with the rust converter, after being treated, and every 250 hours (a total of 1000 hours) of artificial weathering in a Q-lab QUV Weatherometer. The samples were also mounted to a roof top outdoor exposure rack and tested each 30 days. The comparison of outdoor and indoor accelerated weathering was done to try and give some correlation between the weathering types. Samples were exposed to a salt mist in both the outdoor and indoor weathering situations. The salt mist they were exposed to mimics the salt exposure of an Atlantic coastal setting. The methods for testing the samples are; XRD, laser profilometery, thickness coating measurements, gloss, color, photography, and finally visual ranking.

This presentation will give a brief description of this study Phase 1 (presented at AIC/ASG in 2010) and the final results. However the highlight and bulk of this presentation will be this studies’ Phase 2. In Phase 2 of the study we evaluated the best convertor from Phase 1 and added four more commercial available convertors. All samples were exposed to a salt mist to test the rust convertors effectiveness in a marine environment.

The goal of this study is to provide the end user be it home owner, museum conservator, or site manager with the knowledge needed to make an informed decision when selecting a rust converter in both an inland setting and a coastal environment.

avatar for Jason Church

Jason Church

Materials Conservator, National Center for Preservation Technology and Training (NCPTT)
Jason Church is a Materials Conservator in the Materials Conservation Program at the National Center for Preservation Technology and Training (NCPTT) in Natchitoches, LA. NCPTT is a research and training office of the National Park Service. Jason divides his time between original... Read More →


Anna Muto

Intern, NCPTT
avatar for Mary F. Striegel, [Fellow]

Mary F. Striegel, [Fellow]

Chief of Materials Conservation, NCPTT
Mary F. Striegel is Chief of Materials Conservation at the National Center for Preservation Technology and Training. She heads up basic and applied research that focuses on evaluation of preservation treatments for preventing damage to cultural resources. She and her staff undertake... Read More →

Sarah Hunter

Historic Preservation-Student, University of Texas at Austin

Saturday May 31, 2014 2:30pm - 3:00pm PDT
Garden Room