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Posted

A few years back, after spending most of a year with an Elise duet concertina in Afghanistan, I posted a thread here pondering about a durable concertina for travel in tough climates. In some other threads here we've discussed the "campaign concertinas" made for India service and the like, which in some cases had metal-reinforced corners, special (or treated?) woods, and special reed finishes to resist corrosion. At the time the general consensus of the board was that concertinas are pretty reasonably hardy as-is, but the idea of a travel-inclined concertina stuck with me.

 

For a number of years after Afghanistan it didn't matter since I was working desk jobs in Washington DC, but within months of buying a nice Morse Beaumont duet concertina, I joined a buddy's startup consulting firm, moved to Colombia, bounced around Europe, and now working in West Africa. The climate here in Monrovia has very little temperature change (between 70-85F throughout the year) but has a torrential rainy season and baking dry season, plus most of the population lives near the sea; my house is only 200 yards from the ocean. So this climate is tough on a lot of gear: we're constantly dealing with corrosion and gunk on our car, and our leather belts and shoes will literally grow an even coat of fuzzy grey mold if left alone on the shelf a few weeks. And in another few months it'll be dry season, precipitation will drop to near-nil and everything that's been soggy and swollen for months will desiccate and contract, and indoor climate control is largely absent here.

 

I'm having a used $75 plastic-body Stagi Anglo off eBay sent out here to tide me over for the moment, but we're about to start coming into decent cash as this startup finally gains ground, so I'm in conversations with Cnet member Alex Holden, proprietor of the nascent Holden Concertinas, to build me a concertina with all feasible features and tweaks to survive climate extremes and rough handling. Alex has a strong grounding in traditional handicrafts but is also open to working with innovative materials, so we thought we'd put our heads together, and also see if the Cnet community has any input.

 

Here are some of our initial ideas:

  • The base inspiration is the Wheatstone "Duett", an early duet concertina made in rectangular form with 12 buttons per side, about 6" long by 4.5" wide. The square shape should simplify most stages of production and perhaps make it a little more durable. The Duett was in a proto-Maccann system (one chromatic octave per side) but since I do folk music and am used to very limited chromaticity, I'm inclined to use my 12 buttons per side for an octave and three notes, plus one chromatic per side, something like that. I've been simulating this by playing on the Duettina smartphone app and using only C-scale notes and the F#, and I'm getting by fine with that.

2ewfv34.jpg

qnab91.jpg

  • The ends are a fragile point due to being a large single piece of wood, and of course the fretting. We looked at a few different options and the one we're leaning to right now is anodized aluminum ends as being corrosion resistant, slim, light, and breakage resistant. For fretwork we've considered some Deco-influenced rays kind of like the old Bastari metal-ended, since those leave few weak points of thin metal, and also provide an interesting contrast to the more common/anachronistic Victorian motifs still used. Alternately, we could go fretless or do side-fretting, as Bob Tedrow has done on some instruments, in which case we could have some pattern or line image etched into the aluminum ends prior to anodizing.
  • For the frame, I could use some advice about materials. To one degree plywood is more resistant to climate, but still subject to rot and in some cases perhaps delamination? I know some hardwoods are brittle or risk swelling, but if we choose a hardwood with good climate resistance would that cancel out disadvantages? I have a particular fondness for mesquite since I've lived in Texas, and it's a sustainable wood (practically a weed) and very stable, to the point that smallpipe makers in the US use it for instruments. But since Alex is in the UK we're also open to any UK woods that resist climate well, and/or any composites like bamboo ply, etc.
  • For reedblocks, Van Wyck has already set a precedent with making perspex/plexiglass reedblocks for his concertinas in South Africa, so that's one option; other ideas? You can see in the above pic that a Duett reedpan (all equal-size chambers?) is very simply constructed, so we could just epoxy together some cuts of sheet, or since Alex has access to a CNC mill could mill it out of a solid block easily.
  • Soundboard: I understand some North American makers use plywood due to the US having a harsher climate, but would it be too crazy to take it a step further and use carbon fiber? It's already got some popularity for the soundboards of guitars and the like, though I realize "soundboard" has somewhat different meanings in these cases. But it is appealing to diminish risks of cracking by replacing that large piece of wood.
  • Bellows: this is a sticky one, is there anything at all practical to use that's more durable than leather and card? I'm not a rigid stickler so if using different materials would necessitate a more accordion-influenced bellow I'm fine with that, so long as it functions and is durable, or is leather simply unavoidable here?
  • Reeds: anything to be done to make them more corrosion-resistant, or would modern reeds be of sturdier metals than traditional reeds were anyway?

 

These are some of our initial thoughts. Anyone have any red flags to raise, points of note, or clever ideas we should consider? Is anyone else in the market for a "near-bulletproof" travel concertina (in any fingering system) so that we can make the design versatile enough to be applied to several different builds?

 

Right now I'm getting by with a PVC tinwhistle, synthetic Irish flute, polymer Swedish bagpipes, and a micro-MIDI keyboard, and those have all been outstanding packable and durable travel instruments, so I'm looking forward to adding a concertina to that vagabond collection so I can keep up my concertina skills wherever I go.

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Posted

Thanks Matthew. Allow me to chip in with a few extra thoughts of my own:

  1. Valves: any reason not to go with modern accordion-style plastic valves rather than the traditional leather?
  2. Pads: I'm considering experimenting with foamcore and soft silicone rubber.
  3. Reeds: do stainless spring steel tongues seem like a good idea to avoid the potential rust problems with high-carbon spring steel?
Posted

A few quick thoughts, without time to consider them deeply, much less research anything. And I'm long from being a materials expert, so my thoughts spring from random bits of information that I've stumbled across over the years.

  • Valves: any reason not to go with modern accordion-style plastic valves rather than the traditional leather?

Not that I know of, though I don't know how their properties differ from leather and how that might matter. But has anyone tried plastic artificial leathers? They're widely used for shoes these days, but I don't know how much variety is available in their properties. Could there be an artificial leather -- or some other type of plastic -- available that could be used for bellows?

 

  • ends..
  • fretwork...
  • frame...
  • reedblocks...
  • Soundboard...
  • Bellows...
  • Reeds...

 


Carbon fiber mentioned for soundboard, but what about other parts traditionally made from wood? I believe one of our members reported success in making new carbon fiber ends for an Edeophone. Or cast parts in a durable plastic? (What are the acoustical properties of nylon or Kevlar?)

 

If you are going to use wood for any parts, I might suggest that you look into woods used for above-deck and interior work on sailboats, especially those that travel widely in tropical latitudes. But be really thorough in your research and find out how these woods behave under all possible conditions. It might be surprising what can be overlooked, e.g.:

 

I know a schooner that was built by a shipyard that was used to building wooden fishing boats. The deck was -- as was standard practice -- northern (American) white pine. Constantly subjected to salt spray, that didn't rot, but this boat rarely sailed in storms and was kept in harbor during the winter. Soaked with fresh water from melting ice and snow in the spring, the planks rotted. After a bit of research, the owner-captain replaced those planks one by one with (southern) longleaf yellow pine, which resists fresh-water rot.

As for fretwork, a lot must depend on what sort of sound you want... or at least are willing to tolerate. For a louder instrument, you'll want more open fretwork. If you want -- or will accept -- a quieter instrument, what about something like the "dot-comma" pattern of the early (6-sided) Æolas? And are you familiar with the fretwork on Holmwood concertinas?

Posted

This might offend some sensibilities, but how about a bellows made from those rubber (actually neoprene coated nylon) bellows tubes that are used to protect hydraulic pistons from dust in farm equipment, industrial plants etc.

 

Jim MacArthur is using these in his midi concertina project and he told me that they felt/played very similarly to leather bellows. He uses a 5" rectangular bellows from McMaster-Carr 9742K32.

 

If Jim reads this then perhaps he will update his findings.

 

Almost indestructible, easily cleaned, unharmed by mould or mildew. Not particularly cheap, but sold by the foot...

Posted (edited)

This might offend some sensibilities, but how about a bellows made from those rubber (actually neoprene coated nylon) bellows tubes that are used to protect hydraulic pistons from dust in farm equipment, industrial plants etc.

Interesting - I wonder if they are rigid enough to resist ballooning/collapsing when playing hard. If not, maybe the rubberised cloth material is available in sheets that could be glued to a conventional card frame, then the cards painted on the inside with some sort of waterproofing agent?

Edited by alex_holden
Posted

Not that I know of, though I don't know how their properties differ from leather and how that might matter. But has anyone tried plastic artificial leathers? They're widely used for shoes these days, but I don't know how much variety is available in their properties. Could there be an artificial leather -- or some other type of plastic -- available that could be used for bellows?

My worry about artificial leather (at least the types I've seen used in clothing) is whether it can be made thin enough and flexible enough for bellows (particularly the gussets) without making it really weak and/or porous. I've owned bags made of a sort of artificial leather that was basically nylon fabric with a textured paint on the outside, that quickly started to crack and flake off.

 

Carbon fiber mentioned for soundboard, but what about other parts traditionally made from wood? I believe one of our members reported success in making new carbon fiber ends for an Edeophone. Or cast parts in a durable plastic? (What are the acoustical properties of nylon or Kevlar?)

It would be possible to do away with wood entirely, though I'm not sure if it would be worth the extra difficulty or what effect it might have on the sound of the instrument. I think any wooden parts we do include are probably going to spend some time soaking in a bucket of wood-preservative!

Posted

Any decision to go with a four sided box and the pictured layout will be reflected in higher hand pressures needed for a given volume and also different tonal character for the inboard reeds. The closer to round the smaller the square area given the same "diameter"/across the flats size. You could make a very small box with so few buttons.

Posted

The original Duett was fairly dinky; by some quick back-of-the-envelope calcs I get a bellows surface area roughly equivalent to that of a 5 3/4" hexagonal instrument.

 

It'll be interesting to find out much of a difference it makes to the sound that half of the reeds are inboard. My uneducated guess is that the crosspiece between the sides of the bellows frame will help to reduce the effect.

Posted (edited)

You might want to consult with Sam Rizetta, the West Virginia hammered dulcimer builder/player. HE has built kevlar instruments and they sound mighty nice. I know he's done a lot of research about the acoustic properties of various durable materials.

 

http://samrizzetta.com/contact-us/

Edited by Jim Besser
Posted

This might offend some sensibilities, but how about a bellows made from those rubber (actually neoprene coated nylon) bellows tubes that are used to protect hydraulic pistons from dust in farm equipment, industrial plants etc.

 

Going back nearly 50 years to when I worked in a lab testing plastics, I wonder about polypropylene for the bellows?

The point being that it has fantastic flex resistance when used as a hinge (remember those suitcases with integral

polypropylene hinges?).

 

We used to test strips of polypropylene for 'flex resistance' by flexing 'em through 320 degrees on a special machine.

They stood up to tens, if not hundreds of thousands of flexes.

 

Just a thought...

 

Roger

Posted (edited)

Polypropylene for bellows [...] Totally unsuitable. Silicone rubber or Hytrel maybe or even a very flexible Santoprene. But what do I know, we have 25 Injection moulders and a full tool-room, and process around 15000 to 20,000 kg of polymer a week. I have spent many hours talking about non- leather bellows with all and sundry. The tooling would be an utter nightmare to make and run. I have a friend in the village who ran a Rubber Toolmaking Company who was an expert on Bellows tooling, even he went pale at the prospect of doing the job. Nothing would give me greater pleasure than to move the development of our beloved 'Tinas on

Edited by Paul Schwartz
no need to be rude (or daft)
Posted (edited)

I think the cost of tooling up to mould one-piece polymer bellows is going to be out of the question for this project.

 

What we're wondering is: does anyone know of a sheet material with properties that are close enough to leather to replace it in a traditionally constructed bellows without being prone to rotting in a tropical climate? Or perhaps a way to treat/coat leather bellows (inside and out) that would offer better protection, even if it came at the cost of slightly reduced flexibility?

 

Edit: maybe something like this would help?

http://www.wolfschemicals.com/en/termek/wl-2n---nano-leather-sealant--

Edited by alex_holden
Posted

For my midi concertina, I auditioned perhaps a dozen industrial bellows, and found exactly one to be acceptable -- a 5" square model distributed in the USA by McMaster, # 9742K32. That distributor is legendary for not releasing information about the manufacturer, so I can't tell you much more about it, but I can tell you that it works like a charm. Since my concertinas are going to be presents for my teen-age nephews, I designed them to be tough. Over the summer, I put my prototype through a torture test that I would never dream of with a real acoustic concertina. I wore it around on my back, just dangling from its strap. I threw it around. I overextended the bellows. And in the end, not a crack or a tear. As for the feel, the bellows isn't as stiff as the leather in my Stagi, but it's a decent substitute, and never once made me wish that I had something more accurate.

 

That said, for every good bellows, there are plenty of bad ones, including those which are not designed to be air-tight, and those which are too thin to hold up properly. I had such a hard time with the search that once I found one that worked, I designed the rest of the concertina around it.

 

As for the other materials, I've got a real love-hate going with the garolite that I've chosen for the body. Like most composites, it's seriously tough stuff, but it's brutal to work with, dulls tools instantly, shows every scratch, etc. However, I was going for a retro, bakelite look, and that fit the bill perfectly. However, this is a midi concertina, and I suspect that you will need to think long and hard about the resonant properties of your enclosure.

Jim MacA.

Posted

Thanks for the information about the bellows, Jim. I'll discuss them with Matthew.

 

I had to look up Garolite: I know it as FR-4, the type of fibreglass used as the substrate for better quality PCBs. I agree, not very nice stuff to work with, and be careful not to breathe the dust! IME only carbide tools will stand up to it for long.

Posted (edited)

You might have seen my story about the carbon fibre and plywood concertina I made a while ago:

http://www.concertina.net/forums/index.php?showtopic=17788

pictures also found here:

http://www.concertina.net/forums/index.php?showtopic=17788

 

You mentioned the possibility of using a carbon fibre for some components, I would say this about it: it is very very strong and stable. The only thing about it is it seems to have quite a deadening effect on sound, my instrument is rather quiet, though this is probably not helped by the fact I only put small holes in the ends.

 

On the subject of bellows, I think if a product design company were to design and market a concertina now as a new instrument I very very much doubt they would opt to use leather for bellows, a rubber impregnated cloth or some sort of rubber/plastic sounds much more likely. The tooling for it might be hard to make though. I would really like to see someone try this as I suspect the real reason we make bellows from leather and card has much to do with the tastes of players and lack of modern technology research and money to fund such research. Concertinas though popular are quite specialist in the grand scheme of things so most research and innovation seems to be done by individuals rather than large companies with huge budgets.

Edited by Jake of Hertford
Posted

Jake, that's a really cool build! Neat to see someone pushing forward the bounds of concertina technology! And also as much as I enjoy then concertina and appreciate vintage models, I always enjoy seeing people break away from the anachronistic Victorian aesthetic that's become the default. Those bellows papers are gorgeous!

 

So far as carbon fiber: so your assessment is that the carbon fiber ends may be reducing resonance, though the small soundholes add another variable that muddies the issue. That said, do you think that carbon fiber would have the same deadening effect when used as a soundboard such as in Holden's concept? We're planning aluminum ends with relatively standard size cutouts (though in a more Art Deco or Modernist grille pattern) so might the results be different entirely? What did you use for reedblock and soundboard on yours?

 

For bellows, an initial glance seems to show that viable options for finished bellows off-the-shelf are limited and would require modifying the whole design around the bellows. While that's feasible with something like a MIDI instrument where a lot of the physical dimensions matter less, for the purposes of a build like ours it appears we'd be best off making bellows in a relatively standard way, just either using a substitute for leather or by specially treating leather for climate resistance.

Posted (edited)

My worry about artificial leather (at least the types I've seen used in clothing) is whether it can be made thin enough and flexible enough for bellows (particularly the gussets) without making it really weak and/or porous. I've owned bags made of a sort of artificial leather that was basically nylon fabric with a textured paint on the outside, that quickly started to crack and flake off.

I'd call that "imitation leather", not "artificial leather". What I was talking about, which I've seen used in shoes and I think also in some upscale "leather" garments is plastic sheeting with an internal structure imitating that of leather itself.

Edited by JimLucas
Posted

FWIW. There is 'full grain leather' and there is 'bonded leather'.

 

Full grain is the real skin of an animal in a single piece, treated and dyed. Characteristics vary with the animal.

 

Bonded leather is finely ground particles of leather bonded together in a vinyl base. If you have ever wondered why a cheap leather belt stretches and deforms easily then it is not (just) because you are too fat, it is because it is made out of bonded leather. Whenever you see a label that says 'genuine leather' then that really means it is bonded leather.

 

Really genuine leather will be labelled as 'full grain leather' and will be much more expensive.

 

I doubt that you want bonded leather for bellows, it is weak and stretches too readily and is not very durable. Most clothing and furniture is made from bonded leather.

 

Personally, I would not dismiss at least testing Jim's industrial bellows for a small, square campaign concertina.

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