Drumroll please.... here (hear) is the sound of the Esraj with mylar head! Kishan Patel does an amazing job in this performance:

Esraj final

One portion of the rim epoxy came loose after gluing; the job was salvaged by heating and molding the shape of the mylar over the rim, and gluing it completely around the edge with a 3M adhesive, Super 77. The stuff was very gooey and gross to work with, but did the trick- strong tack and fast, durable bond.

Here we are tuning and setting the bridge position:

And it was just in time! Here is a photo from a few days later, in concert with Arijit Mahalanabis, Samir Chatterjee, in the very able hands of Kishan Patel

Esraj head gluing

Here she is stretched on a frame:

and now with epoxy and clamps and weights (I eat heavy peanuts):

Fiberskyn esraj head replacement

I do work on North Indian instruments quite often; sitar, sarod, tabla, etc. People have asked about replacing the traditional sheep or goat skin with a synthetic material, and now I have the opportunity to test it out.

This esraj had a large chip missing from the bottom rim of the bowl. I removed it, squared the edges, and prepared a piece of cedrela oderata which is an excellent match visually and for strength/weight ratio to patch it.

I shaped the new piece to match the rim, and scraped the excess sheep hide and glue from the gluing area of the rim. The patch ties in to a vertical support beam- one that is VERY sturdy- which will carry the string tension through to the neck. I am very confident this repair will hold, even with the very many strings putting tension on the assembly.

The next step is to test adhesives on the Fiberskyn head. Remo makes this excellent synthetic imitation skin. I chose the ambassador weight which is 10 mil thick. This matched a few samples I measured of the sheepskin from the instrument.

The material is mylar, and I opted to test three adhesives: cyanoacrylate (super glue), E 6000 (an industrial adhesive for exterior gluing on cars- recommended by 'the glue guy' at the hardware store) and long-cure epoxy.

I made a scrap assembly resembling the bowl. First I only glue the pieces to the top side of the rim (not wrapping around the edge for extra strength).

I applied some finger pressure, and both the epoxy and super glue broke wood away before giving up the bond. The E6000 bond broke quite easily; I would say I was only applying ca. 20 pound of finger pressue.

Next, I reglued the samples OVER the edge, to add strength. This mimcs the traditional attachment, and will really test the adhesives. Here is the result:

As you can see, I was able to clamp the mylar clear to the bottom of the channel; I would estimate forces in excess of 250 pounds and both the superglue and epoxy held fast. The mylar stretched to accomodate the pressure, and the glue bond held.

However, the E6000 let go after only a few turns of the clamp. Clearly, E6000 adhesive is not formulated to bond mylar.

I will feel very confident using superglue or epoxy. The epoxy was easier to bond the top of the rim with, so I will probably use it for that purpose. The superglue was much easier to use pulling the extra over the edge: the result also looked cleaner, and since that is the most visible part of the repair, I will probably use superglue for that.

Chromatic kalimba: possible tuning layouts

A customer recently asked me about potential note layouts on chromatic kalimbas.

I have crafted instruments with chromatic notes immediately adjacent, in linear ascending fashion, as well as Hugh Tracey style, where the chromatic notes are on the back surface of the instrument. I have also found a nice way to combine approaches, and essentially take the Hugh Tracey diatonic layout, and add chromatic notes adjacent to each pitch. This gives more pitch separation than the linear layout, but less than the Hugh Tracey arrangement.

I am not a physicist, so I have to go on observation of the work I have done.

I have found instruments with chromatic notes closer to each other to have more pitch separation. C and C# have very few overtones in common, so notes struck tend not to excite their neighbor notes by harmonic resonance. If there is a loss in sustain (from the fact that the note is not supported by sympathetic resonance of nearby notes) it is so minimal as to be not noticeable. And, a well-constructed kalimba could be built using dense woods to enhance sustain and clarity.

Hugh Tracey-style puts triad notes (chords) next to each other, giving a harmonic resonance- a very rich sound where the notes tend to blend into a wash of whatever the scale its tuned to. The harmonic similarity is only skin-deep though; if the instrument is tuned to equal temperament, even the I to V relationships are very slightly out of tune, and have little overtones in common. There will still be more overtones of a similar, if not exactly equal, resonant frequency.

Therefore, my idea is that if you want more of a modal, harmonically rich sound (sounds great, but only in the given mode or key) then go Hugh Tracey style and separate the notes as much as possible by grouping into triads. If you are musically more adventurous (most people using chromatics are!) then use whichever key arrangement gives you better access to the notes- the pitch separation will be there and I don't hear a major loss of resonance or damping by neighbor keys,

It is interesting to note that Zimbabwean mbiras are tuned with ascending scale tones immediately adjacent. The right hand notes are half and whole steps apart. There does not seem to be a problem in terms of richness of sound and resonance there!

Banjo 5th string tunnel (dual)

In creating a banjo for a lefty, I decided to tunnel the 5th string. I realize that this would prohibit the instrument from ever being set up right-handed, save carving a new neck. Anticipating that this banjo will be around long enough to potentially be in the hands of a righty, I decided to add dual 5th string tunnels.

The unused channel does not get in the way, negatively affect tone, etc; it only increases the instruments versatility. I also left the fingerboard a constant width to the nut in order to facilitate.

Here is a view of the brass tubes used for tunneling:

The termination of the rods at the nut end looks like this:

A hole is drilled in the nut to allow the string to escape; if the instrument is ever retrofitted for a R.H. player, a new nut would simply be made with the hole drilled on the other side.

Here is a view of the brass tubing exiting the fingerboard just before the 5th fret:

As you can see, I have inserted .020 wound strings in to the hole. These prevent the tubes from crushing during bending, and as you pull them out, clear out any debris or adhesive that may have got in. This fingerboard is ebony, bound in cherry and ebony.

Antique Stanley Pullshave

At the Picadilly Flea Market today (Eugene, OR) I scored this Stanley tool- the seller called it a pull scraper, but I believe it is probably better known as a pullshave. Veritas and Stanley both make modern versions of this tool, but I couldn't seem to find any pictures or references to this old Stanley model, presumably antique.


I know furniture builders use this type of tool to hollow out the inner curve of a chair seat, and wooden boatbuilders would also find it useful for all of the inner curves they work with. I am thinking it could come in handy for luthiery, either in carving necks where I use a spokeshave quite a bit, or in hollowing out the inside of an archtop soundboard.


The modern versions offer an improvement in the addition of a handle above the blade- this would give more control of the cut. At any rate, I think once I tune it up it should be a joy to use! The handle is very comfortable and feels massive- like it has the right mass to balance a steady pull.

I also think its cool that at least two tools in daily use- the vegetable peeler and the shaving razor- operate on the exact same principle. It somehow makes using these tools that much more comfortable.