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.
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. 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.