Archaeological Preservation Research Laboratory Report 10:

Conservation Research Laboratory (CRL) Leather Dressing

C. Wayne Smith

D. L. Hamilton

Conservation Research Laboratory/Archaeological Preservation Research Laboratory

Texas A&M University

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INGREDIENTS:
Polyethylene Glycol (PEG) 4000
PR-12 Silicone Oil
Pigment (optional)

Preparation:

1. 2 parts PEG 4000 to 3 parts PR-12 silicone oil

2. Combine these ingredients in a glass beaker and warm them in an oven heated to 110 degrees Fahrenheit. Mixing will become easier as the mixture warms.  **do not boil the mixture

3. Let the mixture cool slowly. Stir periodically to ensure smoothness.

4. Apply a thin even coat to the surface of the leather and buff with a soft cloth.   

    -For very dry stiff leather, the process can be repeated several times. 

    -If the leather is badly cracked, allow the dressing to soak into the surface before buffing.

5. Periodic applications of this dressing appear to soften stiff dried leather, acting as a humectant. Always off excess dressing before crating the leather artifact.

6. Add pigments such as bone black, graphite or oxides such as iron oxide or titanium dioxide as necessary.

    -Our experiments have indicated that pigment additives should not exceed 3% of the total volume of the solution.

    -Acrylic-based pigments can cause thickening or lumpiness of the leather dressing:  if these must be used to obtain a desired color, make a test batch of the dressing before treating the artifact to ensure that there is no chemical reaction between the coloration and the basic dressing.

7. Store the mixture in a tightly sealed jar. The resultant mixtures form a moderately stiff paste that has a relatively long shelf life. Humidity may affect the consistency of the dressing over a long period of time.

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Citation Information:
C. Wayne Smith
1998, "Conservation Research Laboratory (CRL) Leather Dressing", Archaeological Preservation Research Laboratory (APRIL), Report 10 , World Wide Web, URL, http://nautarch.tamu.edu/APRL/report10.htm, Nautical Archaeology Program, Texas A&M University, College Station, Texas.  

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