The construction process is quite simple and only requires a few supplies.
You'll need an empty propane tank. Try and find a new one that has never been filled to avoid horrific injury. I found my at Wal-Mart in the camping section for $27.
A drill or dremel, a saber, jig, or similar electric saw, hack-saw blade, wrench, file, and electric tuner. If you do not have a tuner, you can use one of several tuner programs that install onto your computer and use a microphone. Try checking http://www.mymusictools.com/download/tuner-software/
for one of these programs.