Ruffatti Pipes

Making Ruffatti Organ Pipes

It may surprise you to know that relatively few organ builders make their own pipes, buying them instead from supply houses. But at Fratelli Ruffatti we make all our own pipes in order to have full control over the tone quality of our instruments. Here is an overview of the pipe-making process in our factory, the same process fine builders have used for centuries.

We make our organ pipes from a variety of woods and metal alloys. However, most of our pipes are made of a tin and lead mixture called spotted metal or metallo tigrato (roughly 50% tin and 50% lead). Here, ingots of tin and lead are placed in a melting pot. We vary the exact ratio of tin to lead based on the desired appearance and tone quality. All else being equal, higher tin content tends to yield a brighter tone and shinier appearance.

Here is a close-up of molten pipe metal in the crucible or melting pot (crogiolo). This metal will be ladled into another container before it is poured.

Once ladled into a secondary pot, the metal is cooled to about 475 degrees, a little above its melting point, (the exact temperature varies with the the alloy). At this temperature it will be the right consistency to flow evenly onto the casting bench.

The metal is poured into a trough at the end of the casting bench. A slit across the back of the trough will meter out the metal as the trough is slid along the length of the bench.

Sliding the trough along the length of the casting bench leaves behind a glistening layer of metal which will form characteristic spots as it cools. The top of the casting bench itself is made of marble and is covered with canvas. The pipe metal will have a smooth and a rough (canvas) side.

Cooled metal is removed from the casting bench.

The sheets of metal are attached to the rotating drum of a planer and planed to the desired thickness.

Sizing (gum arabic and whiting) is applied to the sheets of metal. When a pipe's components are ready to be soldered together, the sizing acts as a sort of "nonstick" surface for the solder, preventing it from flowing except where desired.

Pipe metal is soft and quite malleable. Individual pieces are cut according to patterns and rolled around mandrels to establish their shape. Here a tapered mandrel is used to form the toe of a pipe.

The metal is beaten until it conforms fully to the shape of the mandrel.

The pipe maker now bevels a surface which will be soldered. Beveling exposes fresh metal and removes the sizing so the metal will accept a solder bead. Soldering is a bit tricky because the solder and the pipe metal have almost the same melting point! Look below the man's thumb to see a completed solder seam.

Blocking a reed resonator. Solder is flowed to join the two parts. Note the white sizing on the top surface of the block which prevents the solder from flowing outside the desired area.

A finished pipe is hand-polished. From this point forward pipes which will be visible in the finished instrument must be handled with gloves to keep finger oils from tarnishing them.

Display pipes, like this brass Tromba Pontificale, are lacquered to protect their finish.

Completed pipes are ready to be voiced. Voicing is the process of adjusting the physical alignment of the critical parts (upper and lower lips, languid, etc.) to get the desired sound. This process begins by establishing the cut up, which is the distance from the lower lip to the upper lip of the pipe. Proportional dividers are used to etch a line across the upper lip of the pipe. Principal stops are often cut up 1/4 of the width of their mouth and Flutes are often cut up 1/3, but this depends on the tone desired. Higher cut ups increase the power of the pipe at its fundamental and decrease its upper harmonics.

In this photo you can see the line etched by the proportional dividers. The pipe voicer is using a knife to cut the upper lip to that line. Because cut up affects the tone so dramatically and because the cut can't be undone once it's made (a mistake will return the pipe to the melting pot) the voicer in the shop will generally be conservative with the cut up. The cut up will be increased, if needed, when the organ is regulated after installation.

The rest of the voicing process is a combination of listening, visual examination for proper alignment, and painstaking minute adjustments which must be made until each pipe sounds correct in its own right--and in relation to its neighbors. When all is said and done, the organ is mostly a box of whistles--and a glorious one at that!