Ever since I forged my first singing bowl about 15 years ago, I have accepted the paradigm that hammering the entire surface of a bowl, bell, cymbal or gong is the only way to create a quality and well tuned instrument.
However in the Summer of 2023 I had the opportunity to play a titanium gong created in
America by Ross Barrable (https://crystaniumgongs.com) which appeared to have no hammer marks at all! I was impressed by what a saw and heard, and wanted to learn more about his processes.
(In an online conversation, Ross actually mentioned that he found hammering the entire surface counter productive to his successful tuning process.)
Instead, these gongs are manufactured using a large and powerful hydraulic press in which the sheet metal is formed into a pre-prepared mould.
At this point I think that it is important to look a bit deeper at traditional techniques, especially those used for bowls and cymbals. Genuine Himalayan bowls are entirely hand hammered from CAST bronze blanks (which start out shaped like a thin flying saucer), and are then hammered by skilled teams of artisans, often with 3 or 4 hammers working in perfect rhythm.
As the metal work hardens by the constant hammering (you can actually hear and feel this happening as the sound of the hammering goes up in pitch and the impressions made by each hammer blow get smaller and smaller), it is regularly annealed (softened) by re heating and cooling.
This process is also true of the best quality cymbals. The blank discs are cast, then hammered, and then sometimes lathed to reduce the thickness, and then hammered again… This is a highly skilled craft, hence the very high prices of the finest pieces.
BUT WHAT ABOUT GONGS ?
The most popular gongs available in the West, from companies such as Paiste and my friend Broeder Oetken are made from sheets of nickel silver alloy or bronze, rather than from cast plates. This alloy can very easily be annealed (softened) using a gas flame, allowing a rim to be formed with comparative ease. However the central disc is in most cases left relatively untouched.
I like to think of this central disc as being like the cone of a loudspeaker, with the rim like the supporting and stiff structure that surrounds it. This disc may have a central boss formed on it, or some decorative scratching of the surface in the form of radial , parallel or tangential lines. The final tuning is achieved by the highly skilled application of a relatively few hammer blows, usually from the rear side of the gong.
BUT WHAT ABOUT TITANIUM ?
Titanium has the “unfortunate” quality of being impossible to soften by the conventional method of heating and slow cooling.
Indeed heating actually has the opposite effect of making the metal even harder than before! So all shaping and forging has to be achieved cold and with heavy hammers.
Titanium is also only available from my experience in sheet form. The molten metal has been repeatedly rolled and re-rolled through huge machines, each time being squeezed to tighter tolerances.
The natural crystalline structure of titanium is hexagonal; hence its great strength and stability, and I believe that this is why it is the ideal metal for gongs. However, in this rolling process its molecular or crystalline structure is flattened and stretched in one direction.
A “virgin” sheet of titanium, fresh from the mill, will appear to be equally stiff in all directions, but a few hammer blows will reveal that it is in fact rather like a sheet of corrugated cardboard, stiff in one direction and relatively ‘bendy’ in another.
Thus the molecules have to be returned to be closer to their natural molecular state by hammering, and this is a really long and arduous process.
I did, in the early days of my gong research, invest in a power hammer, thinking that this would greatly speed up the process, but this turned it into such an unpleasant industrial process with little benefit in time saving. I now much prefer to hammer by hand, listening critically to the fall of each hammer blow to ensure that the sheet is exactly in contact with the anvil. This is why titanium gongs take so long to make in comparison to bronze or nickel silver ones.
THE CHALLENGE !
Playing Ross Barrable’s Crystanium gong really raised some questions for me.
Was I spending days literally sweating to hammer every square inch of my gongs for no or little gain?
THE SOLUTION ?
I thought that the only way to find out would be to make two gongs from the same sheet of pure titanium, but to hammer only one and to work on the second in its “virgin” state.
I have just finished these and they are on my website as numbers 24 and 25. They are both forged from 2mm thick grade 1 pure titanium from the same 2m x 1m sheet, giving them a finished diameter of 39 inches.
THIS HAS BEEN A REAL LEARNING CURVE !
The unexpected outcome - The un-hammered sheet has actually taken longer to complete than the hammered version!
As I formed the rim, the relatively asymmetric molecular structure quickly caused the sheet to form a giant “pringle”. I literally spent an extra 2 or 3 days trying to flatten this, clamping it down to a big heavy duty steel table and in the end had to resort to hammers as heavy as 14 lbs in weight to achieve any control. In the end I hammered for almost as long as I would have by working it first with a far more controllable (dead drop) 2 lb hammer, but with far less control.
The second gong, produced by the normal sequence- (Hammering every square inch first, and the rim second), went far more smoothly.
I now have both gongs hung up side by side, and I am listening critically each day as they settle down to see if I can quantify any difference in sound quality.
MY FINDINGS !
The fully hammered gong, number 25, wakes more easily when played with flumies, and is producing more complex harmonics. The un-hammered gong number 24 has a slightly stronger fundamental note, but still responds well to being played with either flumies or mallets.
There is actually not a huge amount of difference in the overall sound quality so far (which I would not have predicted!)
I can only describe their characters as being a little like the difference between a hand made Nepalese bowl and an industrially manufactured glass “crystal” bowl. This may be a matter of individual taste, but personally I much prefer the slight variations and “pulses” that hand made bowls produce. The pure frequencies from “crystal” bowls I find too strident, even sometimes painful if played too loudly!
I will return to hammering in the future!