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Fabric Covered Bellows?


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I noticed entry level Trinity concertinas now come with "fabric covered bellows".  I have a Trinity that I bought new 30+ years ago that has decent standard skived leather bellows. In the pictures the current ones have a fabric-like weave on the outer surface. I wonder if the fabric is just covering some other air-tight material or if these bellows use some kind of doped fabric which has been made air-tight?  Anyone out there have any experience with, or information about them?

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Hi,

You are write about those concertinas, maybe.

https://www.amazon.co.uk/s?k=trinity+college+concertina&dc&ref=a9_sc_1

It depends on how you make the bellows.
The only important thing in a concertina like trinity is the airtightness of the gusset. Because the cardboard on one side of the bellows is all connected.

 

I recently found that all the parts (except the gusset) on the surface of the bellows made in such a way are decorations.

That surface are used book binding tape.

https://www.amazon.co.uk/s?k=book+binding+tape&ref=nb_sb_noss_2

 

However, it seems that concertinas like trinity have a gusset made of synthetic leather, so I think it will deteriorate over time and hole. (I haven't actually confirmed it).

 

I'm trying repair(replace) 4 Trinity like English concertinas this year.

https://concertina.pinefield.asia/gusset-repairs-synthetic-leather-concertina-bellows/#index_id7

 

Traditional concertina bellows are made by cutting a trapezoid from cardboard, facing it, and connecting it in the shape of a butterfly with linen and leather. Therefore, the airtightness of the connection part is required.

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It should be interesting to see how they hold up over time.  I believe my Trinity cost me $600 - $700 When I bought it about 38 years ago.  The leather bellows have held up just fine. I suspect these fabric based bellow won't last that long.

 

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In fairness to the fabric and the bellows, many "better" quality Melodeon/Button Accordion bellows are, as outlined above; on their 4, rather than 6 sides; a continuous 'zig-zag' of folded card.  They are then covered in light fabric ( or simply 'paper' ) and the seams reinforced with a strip of stronger fabric reinforced material.  Many of these bellows have remained serviceable for the best part of 100 or so years and will probably be so for many more years to come.  Even the cheaper, mass produced ones seem to remain sound, although historically, "some" attempts to adapt the gusset material has created 'fails'.  

 

An interesting material which I know Alex has some experience of is Arbetex which is a 'thin', "leather look" synthetic material which he has covered a Concertina 'case' with, I see.  I have used this to replace the 'vinyl'/twill material along the seams of traditional Melodeon Bellows with considerable success ( and economy / ease of use ) and whilst traditionalist would "cringe" it appears it may be a useful material for building viable, lightweight, accordion style, concertina bellows as a 'skin' over continuous 'Z' folded card.

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2 hours ago, Sprunghub said:

An interesting material which I know Alex has some experience of is Arbetex which is a 'thin', "leather look" synthetic material which he has covered a Concertina 'case' with, I see.  I have used this to replace the 'vinyl'/twill material along the seams of traditional Melodeon Bellows with considerable success ( and economy / ease of use ) and whilst traditionalist would "cringe" it appears it may be a useful material for building viable, lightweight, accordion style, concertina bellows as a 'skin' over continuous 'Z' folded card.

 

Arbetex is a woven cotton cloth with a textured leather-effect plastic coating on one side. Interestingly it has a small amount of stretch along the weft and practically none along the warp. Glue doesn't stick very well to the coated side. It's about 0.15mm thick, which is much thinner than the leather I use on traditional bellows. It feels decently flexible and air tight, though I wouldn't like to speculate about its longevity if used as a bellows material.

 

@Pistachio Dreamer might have some useful input.

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On 8/2/2021 at 12:14 PM, alex_holden said:

Arbetex is a woven cotton cloth with a textured leather-effect plastic coating...

..It's about 0.15mm thick, which is much thinner than the leather I use on traditional bellows....

Hm! That's extremely interesting - I could have a non-musical use for that. Thank you.

 

However, Does it come in different thicknesses? The only information I can see gives a thickness

of '...approx. 0.29 - 0.34 mm...'. 

 

Ta.

Edited by lachenal74693
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4 hours ago, lachenal74693 said:

However, Does it come in different thicknesses? The only information I can see gives a thickness

of '...approx. 0.29 - 0.34 mm...'. 

 

I just re-checked it with the correct tool for measuring fabric/leather thickness and it came to 0.36mm. My previous measurement must have been inaccurate because the calipers I used squished it thinner.

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11 minutes ago, alex_holden said:

I just re-checked it with the correct tool for measuring fabric/leather thickness and it came to 0.36mm....

Ah, thank you! That matches the figure I found quite nicely. I did think that 0.15mm sounded a bit thin...

Ta!

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I wouldn't advocate it as a leather substitute, per se, but, as a practical & aesthetic 'skin' ( a la cloth ) over folded single length 'folded' card, Melodeon style bellows - which would lend themselves far more easily to square construction than hexagonal, although not exclusively so, it might make for a viable option. 

 

Not one for the purists and traditionalists, I know!  and gussets are almost certainly still best placed being 'real' leather ( subject to experimentation )

 

Hewitt's seem to sell it principally for book binding - although they reference it as commonly used in the Auto Trade, where it must take some 'wear' for finishing interiors.  I use it for the "spines" on bellows edges and glue the 'non' shiny side using Hewitts PVA / Archive Glue and it shows no signs of suffering, although there is probably much less 'flexing' going on than on a concertina bellows.  The strength of the Arbetex may well allow a reduced 'gsm' in the card which would allow for lighter/more flexible construction. 

 

I have never tried to glue 'to' it's shiny surface - I can see that would raise issues......if I were to ( and will give it a try when next home ) I would give Scotch Weld M3 1099 a go first as I use it for other vinyl related work.  

 

 

 

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Interesting discussion, thanks Alex for alerting me. When I started making bellows sans leather I didn't spend long experimenting with leathercloth - I didn't like it's look and feel on the bellows. I make my own fabric by layering up a cellulose/latex cleaning cloth material with fabric interfacing, with an acrylic fabric medium coating and dubbin providing the finish and greater air-tightness. They are very supple, look great, and easy to maintain with further coats of paint/dubbin. They aren't quite as airtight as leather, which is something I am trying to improve.

 

The other material I have been experimenting with is Kraft-tex paper "leather". This is way too thick, stiff and non-compliant to make bellows in the traditional way, however I've developed a method of making these in tube form that works pretty well, and has the advantage of being much faster to build. The material itself seems incredibly hard wearing, and whilst not quite as supple as leather does seem to break in well over time. I've also been able to assemble these purely using pva, whilst making bellows traditionally with synthetic materials often requires a synthetic adhesive, I've found, particularly to get the gussets to behave.

 

I haven't had any reports of bellows failures yet, though my first instrument made in this way is not even 10 years old by now, and in that time my methods have improved somewhat.

Edited by Pistachio Dreamer
correction
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