Pipe Materials

Organ pipes take a variety of forms, and can be made of several different materials, ranging from paper or bamboo to a selection of metals, including copper, brass, lead and tin. Some of the pipes of at least one organ by Silbermann, built in the early eighteenth century, are made of iron. ⁵ In actual practice, though, the two primary materials used in pipe construction are several species of wood and a limited number of metals.

Historically, several metals have been used in making organ pipes.

• By far the most common metal used in making organ pipes is a mixture called common metal or spotted metal, or even more directly pipe metal. Pipe metal consists of lead and tin melted together, most often using a proportion of about 50% of each. Because the two metals do not combine to form an alloy - - as in the case of bronze or brass, the appearance of pipe metal in which the two components are visibly separate accounts for the name "spotted metal." When less tin is used, the spotted appearance is absent and the name "common metal" is used. Both in the twentieth century and earlier, the percentage of lead and tin has varied throughout the full range of possibilities.
• Lead in almost pure form is found extensively in extant sixteenth and seventeenth century organs, organs from the early part of the twentieth century, and late-twentieth-century copies of earlier instruments.
• Tin is often used in amounts varying from 95% to 100% pure. The metal is strong enough to maintain its shape well, it takes a polished finish, and in the proper thickness provides an excellent resonating chamber in flue pipes.
• Copper is less often used than tin, and finds its most frequent use when pipes are visible.
• Brass is used in two distinct ways in pipe construction.
  • It is used most consistently in the tongues and shallots of reed pipes, where it is essential to the process of making their distinctive sounds.
  • It may be used more visibly in display pipes, where it is most often seen in the resonators of so-called en chamade reeds. These pipes may be made with a flared bell, imitative of the shapes found in orchestral trumpets.
• Zinc is often used for large pipes where a less expensive metal than tin is desired, but high lead content might prove too heavy for the pipe to support its own weight. Zinc pipes are usually painted or lacquered when they will be visible, so that their appearance does not detract from that of the other pipes on display.

Several different woods may also be used in pipe construction, including oak, mahogany, spruce and sugar pine. In some cases the selection is made on the basis of either appearance or availability, but most often a strong, lightweight wood with straight grain is chosen.