Have a butchers at this…
As a conservator working on the collections of Wiltshire museums I have worked on a variety of objects dating from the bronze age onwards but it is not always the oldest items that are the most difficult to deal with. One of the more challenging objects I have had to deal with was a model of a pig from Warminster Museum. Dating from the middle of the 20th century it would once have stood in a butcher’s window.
Figurine before conservation
The figurine was broken and quite dirty in places. Cleaning and repairing it would have been relatively straight forward if it had been made from ceramic or wood but it was actually made from a material called composition. Composition was widely used before modern plastics were developed. Most commonly it was used to make dolls and decorative pieces. There was no standard recipe for making composition but it generally consisted of glue mixed with sawdust or plaster dust and other materials to thicken it and bulk it out. Composition can be a difficult material for a conservator to work with. This is because the glue in the mixture is often still soluble in many of the solvents that we use to clean objects. Use of these including water would cause the composition to soften or dissolve. The various types of paint on the object would also be soluble in some solvents. Various solvents were tested on some tiny samples of the composition and the paint on the object was also tested.
After all this testing I found that the only solvent that was safe to use on the object was white spirit. Unfortunately white spirit on its own did not dissolve the dirt. I was however able to add a detergent to the white spirit and with this mixture I removed most of the dirt on the object. I cleaned a small area at a time using cotton wool swabs and then went over the area again with white spirit to remove any residue of the detergent.
Cleaning in progress
Once I had cleaned the object I then had to find a way of putting it back together and I found I had another problem. Some of the composition around where it has broken was bent out of shape. I am not entirely sure why this had happened, possibly the base of the object had got damp at some point and the dampness softened the composition enough for it to bend out of shape. This meant that I would either have to stick the base on at a strange angle and be left with a large gap to fill or find a way of bending the composition back. I had not faced this problem before but I did some research and found some information that if you brushed a small amount of water on to the composition it would soften enough to bend it slightly which is what I did in the end. Once the composition had dried in its new position I could stick the pieces back together. At this point I had the same problem I had when trying to clean the object in that most adhesives contain solvents which would dissolve the edges of the fragments I was trying to stick together. Luckily I did have one adhesive that used white spirit as its solvent.
Fixing the base
There were various small gaps left around the joins where the fragments had been joined back together. In order to strengthen the joins these gaps were filled in. the filler was made with glass microballoons with the same adhesive the fragments were stuck together with. Glass microballoons are microscopic bubbles of glass conservators often use them as they make a lightweight filling material when mixed with an adhesive. The fills were then painted so that they would blend in. in conservation work touching in is often left a slightly different colour to the surrounding material so that repairs can be seen when examined closely but are a close enough match so as not to be distracting when seen by a museum visitor.
The finished article