No longer pipe dreams - cleaning strategy for pipe organs
Pipe organs are one of the oldest instruments which are still used in European and classical music. They are often decorated beautifully and some, for example those which date back to the baroque era, display ornate carvings and cherubs on their cases. Used to play both ecclesiastical and secular music, the history of this instrument dates back to Ancient Greece, for which the wind supply was created with water pressure. Built for churches and concert halls the organ pipe is an integral part of European musical and cultural heritage. Many organ pipes have been built from lead and lead-tin alloys. Over the years the indoor atmosphere has lead to corrosion of these pipes. Because of the delicate nature of the instrument there are no effective methods and products to clean these pipes. This EU funded project COLLAPSE had the goal of developing new methods for cleaning and preventing damage and of presenting guidelines for a European conservation strategy. As part of this project, researchers based in Sweden have developed a new and effective method of cleaning corroded organ pipes. They have now presented their results on this. They explain that cleaning the corroded pipe is done to decrease the rate of corrosion by removing salts from the surface. However, the difficulty lies in cleaning without removing the insoluble corrosion products such as the lead white. They pioneered the use of water leaching of the corroded pipes from the pipe foot area. This is a process of extraction of a solid mixture. For it to be a success, all the solute should have been dissolved by the solvent yet none of the carrier would have dissolved. They suggest that ultrasonic agitation be used to decrease the leaching time. The suitable leaching time depends on how much corrosion damage has been done and the shape of the pipe foot. These findings stress however that it is not advisable to clean the corroded pipes with water if the environment is still corrosive.
