Body is 1/2″ (nominal ID) Schedule 40 PVC, chosen for a bore diameter that approximately matches a standard soprano clarinet mouthpiece. Barrel is 3/4″ (nominal OD) CPVC coupling, chosen because the mouthpiece just about fits into it. I had to open up the hole just a little with sandpaper. CPVC and PVC dimensions aren’t compatible, though, and the barrel slips loosely over 1/2″ Schedule 40 PVC. So I wrapped a couple of layers of electrical tape around the top of the body. Not as pretty as thread nor as effective as cork, but way easier and cheaper.
Fingering is inspired by that of “The $5.00 Clarinet” from FolkUrban Music, but I didn’t try to scale its dimensions — which are a little unclear anyway; he says the lowest note is Middle C, but the instrument seems too long for that to possibly be true… except that he never says exactly how long the whole instrument is. Instead I used formulas from a book by Nederveen in a spreadsheet to estimate hole diameters and locations.
Clarinets since the earliest days (Denner, ca. 1700) have had at least a couple of keys, because a clarinet overblows at the twelfth; this means you want at least eleven notes in the low (chalumeau) register, so you need ten holes, and it’s hard to control ten holes and hold the instrument up with ten fingers. Denner’s solution was to have two holes normally closed with keys, leaving only eight holes to be covered by the fingers. The FolkUrban design instead makes use of the left little finger, which along with the right thumb is normally is unused on simple woodwinds, and has two holes covered by the left thumb.
Originally I’d wanted to make an A clarinet (that is, one whose easy scale in the clarino register is A major; its lowest note would be D below Middle C), but I discovered a problem: in order to get all the holes close enough together to be within reach, some of the holes want to be quite small. I couldn’t find a solution, in fact, that didn’t use holes too small to work properly. So I abandoned that concept and built it in D (lowest note A below Middle C). For some reason I found almost all the holes had to be drilled smaller than the spreadsheet predicted. I tried to start with too-small drills expecting to widen the holes, but in several cases the too-small holes turned out to be slightly too large.
I departed from the FolkUrban design with the mouthpiece. I wasn’t too keen on their homemade mouthpiece design, and I figured, why bother? I have a mouthpiece. (I have clarinets, too, of course. But if you want to be that kind of pragmatic, my other clarinets are in Bb and Eb, which makes them a pain in the butt for playing tunes in G and D, the near-universal keys of morris and contradance music.)
Some of the notes are kind of stuffy sounding, and trying to keep that many holes covered with the fingers (in a layout that probably isn’t really optimal) is challenging. Nevertheless, I can get a diatonic scale over a range of a little more than two octaves. Accidentals I haven’t tried much, but some at least seem to require half-holing.
I haven’t found anything to take the markings off the PVC yet. Acetone is supposed to work, but the acetone-based nail polish remover I tried didn’t do it. Nor did isopropyl alcohol. I’ll keep trying.
Maybe next I’ll learn to make keys.