When conserving a flaking oil painting, choosing the right consolidant is critical. Two commonly used materials are acrylic resins, such as Paraloid B-72, and rabbit skin glue (RSG). While both have their place in conservation history, they behave very differently—and each comes with distinct advantages and disadvantages.
Acrylic Consolidants: Stable and Reversible
Acrylic consolidants like Paraloid B-72 are widely used in modern conservation for their chemical stability, reversibility, and resistance to moisture. These synthetic resins can be tailored in concentration and solvent to suit delicate paint surfaces, whether applied by brush, syringe, or as a fine mist.
Advantages:
- Excellent aging properties: Acrylics remain flexible and stable over time.
- Reversibility: Easily removed with common conservation solvents such as acetone or ethanol.
- Low moisture sensitivity: Acrylics do not swell or shrink with humidity, making them ideal for fluctuating environments.
- Precision control: Viscosity and application can be finely adjusted for the specific needs of a painting.
Disadvantages:
- Limited penetration: Solvent-based acrylics may not flow easily into tight cracks or absorbent grounds.
- Application concerns: Overuse can cause glossiness or darkening of the paint surface.
- Health and safety: Require careful ventilation and handling due to volatile solvents.
Rabbit Skin Glue: A Traditional Approach with Limitations
Rabbit skin glue has been used for centuries as a consolidant and ground preparation. It remains valued for its strong adhesion and compatibility with traditional materials, especially on chalk grounds.
Advantages:
- Excellent penetration: When applied warm, RSG seeps effectively into fine cracks and loose layers.
- Historic compatibility: Matches well with traditional oil painting techniques and materials.
- Minimal surface alteration: Leaves little visual trace when used correctly.
Disadvantages:
- Highly moisture sensitive: RSG is hygroscopic and responds poorly to changes in humidity, potentially leading to renewed flaking.
- Poor long-term ageing: Over time, RSG becomes brittle and can discolour or lose adhesion.
- Biological risks: As a protein glue, it is susceptible to mould and insects.
- Challenging handling: Needs to be kept warm during use and has a short working time.
Which Should You Use?
Modern conservation practice tends to favour acrylic resins for their predictability, durability, and reversibility, especially when treating artworks that may face varying environmental conditions. Rabbit skin glue may still have a role in certain traditional restorations but is less commonly used today due to its vulnerabilities.
Each case, however, is unique. The condition of the paint, the type of ground, and the history of the artwork all influence the choice of consolidant. At Expert Art Restorer, every treatment is tailored to the specific needs of the painting, guided by conservation best practice and a deep respect for historical materials.
Need advice on a flaking painting?
Contact me to discuss your conservation needs or request a condition assessment.