A what? . . . A pan-jo, dummy! That is, a banjo that is made from a pan. It turns out that you can make beautiful music from a humble pizza pan, plus a stick, a doggy bowl, and a limited number of special parts. And it’s quite a looker, as you can see from the picture, showing a G6 (guitar tuning) panjo with metal strings next to a C6 (uke tuning) panjo with plastic strings. Recipe and sound samples inside.
The most essential component of any string instrument isn’t really the strings, but the solid surface that the strings lie on, also known as the soundboard. Guitars and ukuleles have a soundboard made of wood. Sometimes it is plastic or natural skin, as in the banjo. Sometimes, as in the resonator guitar, it’s made of metal. Metal is great because it transmits rather than absorbs the sound, which gives great volume and sustain, but it tends to have its own “ring,” which mixes with the sound of the strings and muddles it.
Steel and bronze are like this, and this is why people use them to make bells. For a soundboard, you need a metal that sounds more like “thud” than “ding” when you drop it on the floor. Among the common metals, I have found that simple aluminum works great. So the first item to get is a flat, or nearly flat, piece of aluminum of the right size and thickness. Foil is too thin and weak, plate to thick and heavy. The virtue is in the middle, something like a pizza pan (rimless) or a cake pan (3 inch rim, typically), which are the right thickness. You can get a new one for around 5 bucks, or use a recycled one from your kitchen. The instruments in the picture have 12 inch and 9 inch pizza pans, respectively.
To complete the body, you can use another pan (with rim), a cookie tin (less than ideal because it has a dominant resonance, as noted above) or, in my instruments, a stainless dog bowl. Mine cost 3 bucks each at a local thrift store. Make sure it’s the same size as your pan, and join the two together with paper clamps (remove the wire arms or they’ll rattle). One thing to note is that you really don’t need to make a sound hole, so long as the gap between the pan (slightly bent, after mounting) and the rest of the body allows air to go in and out. This is the real function of a sound hole, and research has found that its perimeter, which would be quite large in the case of a gap between the pan and the body, is more important that its total surface.
Now that you have the body, you only need everything else. No sweat. The neck can be made from a piece of 1×2 inch board (four strings, use 1×3 for six strings), from the local hardware store. Maple, hickory, or oak are best for steel strings because it needs to be very strong. Those woods are also best for mounting the frets directly on them. But they are heavy. If you want lightness, go for mahogany, but only for plastic strings. Don’t use pine: it’s too weak and warps over time.
You’ll need to shape the wood a little:
- Reduce one end to 1/2 inch thickness so you can mount the tuners (the original 3/4 inch thickness is too much). About 5 inches is enough for four tuners. This will become the headstock (left end, in the picture).
- Round the two edges opposite the surface you just reduced, from the spot where the headstock begins, all the way to where the body will be attached. This is to make it more comfortable for your thumb while you play.
- You may need to make a pocket, only 1/4 inch deep, around the spot where the middle of the body will end up, in order to accommodate the flying bridge so it doesn’t touch the board (more on this later). If your board has a natural bend, you may be able to avoid making this pocket if you set the neck so it bends backwards.
- As for length, make sure the board is long enough so it protrudes beyond the other side of the body. You’ll need about an inch for mounting hardware plus some space to attach the strings.
After this, you are ready to sand, stain, and finish the wood. Drilling and fretting is best done with the wood already finished. I like a couple coats of Danish oil, which penetrates the wood, followed the day after by a single coat of spray shellac.
Next you add some hardware. You will need these:
- Tuning pegs
- Fret wire
- Wood screws
- Screw eyes
- Retainers (if you don’t want to drill the body)
- Flying bridge (optional)
- String bushings (optional)
- Strap buttons (optional)
- Strings (duh)
The screws, washers, etc. can be found at your local hardware store. By “retainer” I mean a piece of stiff metal with a hole for a screw rather off-center, so that most of it sticks to one side when screwed in. If you can’t find one like this, you can make two by cutting a two-hole angle bracket down the middle. The other items are rather special (though not expensive), and can be found in online stores for cigar box guitars such as CBGitty.com.
The tuning pegs need pretty large holes in the headstock. Be careful drilling them so you don’t mess up the wood. There are special bits for largish holes in wood, which are available at hardware stores. While you are at it with the drill, make pilot holes for the screw eyes, near the bottom end of the headstock and still within it, and for strings at the far end of the whole thing. Be careful spacing both sets since these will determine the position of the strings. I’ve found that a 10mm separation between consecutive holes works well with four strings on 1×2 board.
Fretting could be done at this point, or after a first assembly so you know exactly where you want the bridge to be. You start by deciding what the scale length of the instrument is going to be. This is the distance between the nut (near the headstock) and the bridge (around the middle of the body, though often it is a little off-center for esthetic reasons). Take a pencil and mark both positions on the neck, measure the distance and call it L. Now grab a piece of paper and make two rows of cells. The top will be marked 0 to n, where n is the number of frets you want to end with. On the bottom row, white the measurement L (I like millimeters, which are more precise than inches) right underneath the zero. To fill the rest of the cells on the bottom row, multiply the value on its left by the factor f = (0.5)^(1/12) = 0.9438743. For instance, if your scale length is 20 inches = 500 mm, the table will end up looking like this:
and so on for the rest of the frets. These are the distances from each fret to the bridge, with 0 being the nut. Using a long enough ruler, pencil the fret positions on the neck. The reason why it is better to measure always from the bridge is to avoid accumulating errors that will end up causing a bad intonation.
You will gather from the pictures above that, rather than a proper nut, I like to use a “zero fret” instead. The screw eyes provide lateral positioning for the strings so long as they are lower on the neck than the zero fret. To install the frets properly, you need to cut a groove that is perfectly perpendicular to the neck centerline, for which the best is a miter box. The width of the kerf is also important, so the frets go in without undue hammering, but securely, which requires a rather thick saw. You can find a miter for 1×2 board and a perfect fretting saw at CBGitty.com. The fret wire will need a compound-action cutter because it’s pretty thick. Press the cut wire into the grooves, and then file off the excess wire with a regular flat file angled at 45 degrees.
Now you are ready to attach the body, if you didn’t try it earlier (must be removed for drilling and fretting). I like attaching the pizza pan to the back of the neck with screws on either side rather than drilling through the pan itself. If you do this, you may likely need some washers to get the right pressure on the pan and distance to the neck (maybe also a nut for balance). Refer to the pictures for details. At the end, the pizza plate should contact the neck only around the attachment points, so there is a gap in-between. Otherwise the neck will dampen the sound and possibly cause a rattle.
Install the strings before adding the bridge. With metal strings, you will need to reinforce the upper part of the string holes so the strings don’t cut into the wood (hence the bushings), and possibly add some little nuts or more bushings on the bottom side as well. My preferred bridge is u-shaped so the strings rest on its body and its two legs rest on the pizza pan, leaving a gap between the bridge and the neck. Otherwise, the vibration will never make it to the soundboard. This should be easy if you made a pocket on the neck. Shallow notches on the top of the bridge will help to keep the strings from sliding sideways. You can make your own bridge out of neck material, but I think getting it ready-made from CBGitty.com is worth the small price. Don’t cut the legs just yet, as I did with one of my panjos, forcing me to add little metal shims later on. The correct leg length will be found when setting the action.
Next is finding the correct position for the bridge. This is best done with a clip-on tuner. With the bridge located at its theoretical position, tune the first and fourth strings to their correct pitches. Then press them against the twelfth fret and see if you get exactly one octave up. If it is sharp, that means you need to move that side of the bridge a little away from the nut; if flat, you need to move it toward the nut. Work by small increments, re-tuning those two strings every time (the other two will take care of themselves). When the octaves fret correctly, you may end up with a skewed bridge, which is perfectly normal and even rather cool. Pencil the bridge position on the neck so you can find it again without repeating the process. Likely, the bridge will end up father from the nut than originally calculated, especially with metal strings. Take this into account when you cut the neck pocket.
The final adjustment is the action, that is, the distance between strings and frets. Typically the best is around 3 mm, measured at the twelfth fret, but it may vary due to string tension, curvature of the neck, and your playing style. You want to go as low as possible but without causing buzzes. In practice, it is best to sand the bottom of the bridge legs little by little until it feels comfortable, but before you get buzzes with vigorous play. If you go too far, you can shim the legs a little with plastic or metal tape, but this adds flexibility where you want stiffness, so better not.
And that’s it! You will continue polishing the setup as you play it, but nothing really major. I like to add strap buttons and piezo pickups (lots of room on the backside of the pan), and some markers made with aluminum tape. You want to hear my panjos? Here are some samples taken with the computer’s built-in and rather awful microphone:
Big panjo, tuned G6 with electric guitar strings, 23 inch nominal scale; 12-inch pizza pan and matching doggy bowl:
Small panjo, tuned C6 with tenor ukulele strings, 18 inch nominal scale, later reduced by one fret because the zero fret was too close to the pegs, making some chords hard to play; 9-inch pizza pan and matching doggy bowl:
By the way, this construction method allows you to swap bodies quite easily, keeping neck, strings, etc. in one piece. Look at what happens when you attach a tunable hand drum instead of the pizza pan + dog bowl combo. You get a banjo! And it only takes a few minutes.