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Building English Bellows.


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All good stuff folks, but can anyone be specific about what brand of glue to use for applying the decorative bellows papers? I know it has to be water-based and water-soluble, so that some poor soul can remove then in 100 years time, but what do I actually buy?

 

Albeit the advice had positively been not to chose it I was using a "Pritt stick" to, as long as I can tell after one year of heavy use of the instrument, pretty good success... :)

 

I then sealed the papers with "Acryl medium", which is great for that purpose...

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  • 2 months later...

Hi All,

 

Thanks for everyone's continued input. It really is appreciated.

 

Well I think I am nearly ready to begin building. I have most of the materials and the time to get it done.

 

Here are my final thoughts before I dive in.

 

I'm going to go the route of Tedrow. There seems to be much less finnicky work and room for error. By this I mean starting with long lengths of card rather than individual cards. I think I will go with a 30mm depth for the cards.

 

I will build the internal wooden jig once I know the size of the internal "plane". I could calculate this mathematically but measuring it seems easier and more accurate.

 

I purchased three thicknesses of card (0.87mm, 0.96mm, 1.335mm (black)). I think I will use the 0.87mm as the 0.96mm seems to be a laminate and the black card is too thick. the 0.87mm's surface is glossy but I will hit it with a little sandpaper where the glue will be. It took a lot of research to find what I could have easily measured, but for the sake of anyone else reading this Australia uses the GSM (grams/m2) to measure the weight (and thus ~thickness) of paper/card stock. The first two cards are 600gsm and the thickest card is 1000gsm.

 

I got 2 skins of chrome tanned kangaroo gloving leather from Packer that are ~0.38mm and ~0.48mm. I will use the thicker leather. It is relatively stretchy which will make it difficult to skive no doubt. My local sharpener is currently making me two skiving blades with opposite orientations which should allow me to get a consistent edge skive. I've been practising my skiving on a piece of plate glass and after a few hrs of practice, make far less mistakes.

 

I ended up simply buying some white cotton at Spotlight to use for hinging. It is thin and cheap. They did have cotton hemming tape that looked very thin. However, it was more expensive than the other.

 

For the fabric to card bonds I will use Helmar's Premium Craft Glue. It is acid free, and, by the smell of it, acetone based meaning quick drying. I don't see why I can't use this for leather to card bonds as well. I have plenty of PVA around though if anyone can see an issue with this.

 

I will use hide glue for the cloth end run the same as Bob uses. I like the idea of having this extra reinforcing layer under the leather end runs.

 

Thanks again everyone for the help.

 

I'll keep you posted on the progress.

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Well I'm two days in and have learnt plenty of lessons. I've cut about twice as many cards as I needed. I think I should measure three times not twice.

 

I did lots of experimenting in order to determine my final materials and the method I was going to use for construction.

 

The card I used wasn't available in a large enough size so I have to opt for a middle ground between the Tedrow method (cards cut long and glued into a concertina'ed board) and a single card construction.

 

I was going to use PVA, but it tended to cause the cards to expand and then tear under tension. The hobby glue works very well.

 

I ended up using 100% cotton Voile for the fabric hinges. It was very thin and glued well.

 

Tomorrow's jobs will be cutting the cards and gluing them into 6 "side sets". Then building the jig to do all the final gluing etc.

 

post-11212-0-24556600-1411813195_thumb.jpg

Plenty of cards and supplies.

 

post-11212-0-64652200-1411813177_thumb.jpg

End of day two.

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I got a little side tracked today, but managed to get the cards cut and glued into each of the six sets.

 

I'm pleased with how everything is going. It's very time consuming but methodical which suits me fine. The cards have so little friction when I push and pull them. them. Maybe I've gone too light on the construction. Eh I'll know in a few years.

 

Hopefully I will get the jig made tomorrow. I fear I may be stuck then for a little while until my new skivers are finished.

 

I'm not sure yet whether to make the gussets Tedrow style (a long strip with a full edge skive on both sides then cut to gusset lengths) or the diamond-ish shape that I've seen in a few places. Once I get the skivers and have a bit of practice, I might be able to make a better decision.

 

Here're a few more pics

 

post-11212-0-49413300-1411895155_thumb.jpg

 

Lenghts of cards cut to size. After completing this step I realised I had made extra stock to allow for a few dodgy cards. However I ended up making enough stock to create two sets. Aren't I smart.

 

post-11212-0-37922300-1411895179_thumb.jpg

 

Side sets in varying levels of completion.

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I use a modified Tedrow method, the gummed linen tape, 1-1/2 oz goatskin (1 oz also works), and PVA. The PVA means that the bellows take longer to break in, but I have found that working with PVA or the modified PVA specifically for leather work is much easier. For skiving in low volumes a "safety skiver" and some blades (I like the one that looks like a curved paring knife) works for me.

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  • 1 year later...

After carrying out leather work, what do you folks use for finishing the leather?

What about staining for a uniform finish before final finish?

Lacquer maybe for sealing the colour?

Gloss, semi-gloss or satin?

 

I've seen some water-based lacquers but am a little reluctant to use.

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(In response to SteveS)

I'm certainly no expert but on a recommendation, although I can't remember who gave it, I used Fiebing's acrylic Resolene on a set of scuffed and dried out black bellows and it worked great. Available in neutral, brown and black. I used the black which was effective as a dye and top finish. It dried to a finish that was between satin and gloss I thought. I bought mine through Ebay.

http://www.fiebing.com/catalogue/top-finishes/

Edited by Defra
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Regarding grain direction, I cut my top runs parallel to the spine and not yoo near the belly. They still have enough stretch do if you wet the ,rather as you go around a corner, it will pull in and make an unbunched corner, but won't stretch dry around the perimeter. The stretch direction is across the fold, making closing the bellows easier. Stretch should always be across the hinge. I use .65 mm top runs, but skive the roughly 16-28 mm strip so it tapers from a third of the way in to nothing at the edge. I like a little thickness in the center to help create a rounded ridge rather than something that telegraphs the edge of the card underneath. I bevel my cards at 45 degrees ( using a mat cutter ) so the leather isn't forces to stretch over square corners. It makes a nice shape when closed. Skive all your edges. My top run skive match my butterfly skive so when I glue them together they make a nearly level scarf joint. I don't like to see the surfaces below the leather telegraphed through. The butterfly / gusset joint is also a nice smooth scarf joint.

Dana

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  • 1 month later...
  • 2 weeks later...

I've seen veg tanned goat skin hides as well as chrome tanned.

Any opinions as to which is better for bellows building?

 

I'm speculating here, but from what little I know of chemistry and biochemistry I might guess that chrome-tanned would be more resistent to mold/mildew, especially in a humid environment.

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  • 3 months later...

This thread has been a very interesting and informative read - I hope I'm not committing a faux pas by resurrecting it a few months later.

 

I do so because I've been pondering the construction of the barrel-type jig one sees on Bob Tedrow's site or in David Hornett's photos earlier in this thread. John Smith mentioned:

 

I will build the internal wooden jig once I know the size of the internal "plane". I could calculate this mathematically but measuring it seems easier and more accurate.

 

 

Does anyone here have a suggestion as to what this calculation would be? I think I should like to be able to make a jig prior to starting to cut cards and so forth, but I can't guess at this inner plane size. I hypothesise that it must be some function of (1) the outer plane size, (2) the bellows card/fold depth, and (3) the angle of those cards at maximum extension.

 

The first two variables are easy, but the third I cannot guess at. Is this angle an constant unavoidable facet of the geometry of the bellows? Or is it itself determined by other factors, such as the number of sides, or the angle the trapeziums are cut at? Has anyone here ever made their jig before starting a bellows, and had the maths work out?

 

I am very much obliged to you all for your experience, and for putting it down in threads like this.

 

Matt

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Matt,

 

I just measured the jig, and the dimensions of the parallel sides of the hexagons is 100mm. In the end I chose the easy route. I took my old bellows off and, at full extension, carefully measured the internal dimension. I then completely ignored that value, built them slightly undersized, and packed them out with a layer or two of cardboard on each face. I pulled the old bellows over the jig a few times to confirm it was right size. Once I was happy with the fit I wrapped a few layers of cling wrap around it so that any glue seep wouldn't stick my bellows to the form.

 

Including the card that I added, the dimensions are closer to 103mm. After having used the jig, I realise that that dimension is important but far less critical than I first imagined. It could fit within a range of dimensions but the in order for the gussets to be stable (i.e. not push in and out as you change bellows direction) they can't be too large. Nor can they be too small as then the bellows won't fully extend making them inefficient. There is a reason that most concertinas are of similar dimensions and that the bellows for larger and smaller tinas are likely scaled.

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This thread has been a very interesting and informative read - I hope I'm not committing a faux pas by resurrecting it a few months later.

 

I do so because I've been pondering the construction of the barrel-type jig one sees on Bob Tedrow's site or in David Hornett's photos earlier in this thread. John Smith mentioned:

 

I will build the internal wooden jig once I know the size of the internal "plane". I could calculate this mathematically but measuring it seems easier and more accurate.

 

 

Does anyone here have a suggestion as to what this calculation would be? I think I should like to be able to make a jig prior to starting to cut cards and so forth, but I can't guess at this inner plane size. I hypothesise that it must be some function of (1) the outer plane size, (2) the bellows card/fold depth, and (3) the angle of those cards at maximum extension.

 

The first two variables are easy, but the third I cannot guess at. Is this angle an constant unavoidable facet of the geometry of the bellows? Or is it itself determined by other factors, such as the number of sides, or the angle the trapeziums are cut at? Has anyone here ever made their jig before starting a bellows, and had the maths work out?

 

I am very much obliged to you all for your experience, and for putting it down in threads like this.

 

Matt

 

Hi there,
One very knowledgeable and credible source of information regarding concertina restoration showed me his bellows jig last year - a carton poster mailing tube. Cheap, easy to get hold of, available in lots of sizes, easy to adapt (shouldn't be too hard add some kind of support structure to make it support hexagonal or octagonal shapes), and no big loss if you goof it up. If corrugated cardboard happens to be insufficient a base material - they also come in plastic (eg http://italplast.com.au/Store/index.php?cPath=103_110).You could also consider sewage pipes (for example http://www.polygonpipe.com/4-PVC-U-sewage-1.html).
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