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Bellows Patching

Text and photos by Bob DeVellis (bob_devellis@unc.edu)

This weekend, I patched some worn corners on my Lachenal's bellows and I thought I'd share my experiences.

I should begin by expressing my heartfelt thanks to Bob Tedrow. In addition to being the source of the amazingly thin (.004 in.) leather I used, he was also the source of patient and extremely helpful advice. After talking to Bob at Homewood, I ordered a piece of this remarkable leather. You can literally read through this stuff. I wonder if it's actually "hide" or some sort of membrane from the innards of some type of critter. In any case, it looks and feels a lot like tracing paper, but with more of a cream color. Cream color? the Lachenal's bellows are dark green! Not to worry. Bob Tedrow advised me to get some Fiebings's leather dye; at a shoe repair shop. I looked along the assortment on the shelf and there it was -- Lachenal Bellows Green ... Not. But Bob had already told me that mixing Green and Black would work and indeed it did. The dye comes in bottles with a foil seal under the cap. I punched a couple of small holes in opposite sides of the foil (beer can style, for those of us of the pre-tab-open vintage), which gave me better control pouring the stuff into a third container. I started with roughly 2/3 green and 1/3 black and added a bit of each until the color looked right when daubed on a piece of paper and the excess was wiped off. Actually a very good match resulted. The dye drys a bit lighter than it appears wet. I then took the dauber that came with the dye and applied the mixture to both sides of the leather (called Zephyr leather, Bob tells me, and used in repairing pump organ bellows, I believe he said). Smeared it on, waited a few seconds and wiped it off. After it was reasonably dry, I held it next to the instrument and the match was very good indeed. I let it dry over night.

Meanwhile, I went to the local art supply store in search of rabbit hide glue. It was there, but labelled "rabbit sizing." There were jars of the stuff for about $36 and small packets for about $6. I opted for the latter. The directions on the package said to dump the contents into 3/4 of a cup of water. But reading what I could find on the net for hide glue (of which this is a specific type) suggested that for gluing (as opposed to sizing canvas), a ratio, by volume of 1:1 or 1.5:1 (water to glue) was more like it. Bob had suggested a final consistency close to that of warmed honey, but I had no idea how the cold stuff would differ from the warm stuff. So, I measured 2 rounded teaspoonfuls of glue crystals and about the equivalent of 3 rounded teaspoonfuls of water to into a small jar, sealed it, and let it soak over night.

The glue needs to work at a temperature of between 140 and 160 degrees F. Fortunately, our stove is of a type, more common in Europe than the US, that has electrically powered solid cast iron burners. Although it's slow to reach its working temperature, it holds that temperature within a very small range. So, I put a cast aluminum pan on the stove and in it, I put two glass jars, one with the rehydrated glue and one with just water. I filled the pan with water of the same temperature, stuck a darkroom thermometer into the jar of water, and turned on the stove at its lowest setting. This brought the whole assemblage up to temperature very slowly but allowed me to get dead on about 142 degrees F. I was able to hold that temperature to within a couple of degrees for the full time of the job, with a one-hour lunch break in the middle -- total time, about 4 hours.

In the meantime, I had cut strips of leather that I had pre-measured to be narrow enough to go over the ridge of the bellows fold without covering the decorative papers. This requirement results in fairly narrow strips. I was concerned that this might not quite do it for a couple of badly worn corners. Bob had suggested applying two layers to corners that were in bad shape. So, I cut small rectangular patches that I planned to apply across, rather than along, the ridge at the corner. That is, these would run perpendicular to the longer patches, which would follow the axis of the bellows fold. The bellows papers don't extend fully into the corners, so there was more room here for a patch without covering them.

As per Bob T's instructions, I "titrated" the viscosity of the glue once it was up to temperature by adding either a bit of water or a bit of dried glue crystals, and stirring. this worked very well and allowed me to maintain what seemed to me a good working consistency.

I then dunked a small patch in the glue, using long tweezers, and applied it to a bellows corner. As Bob had suggested, I smoothed it out with a Q-tip dunked in hot water. I did a couple of these and broke for lunch, leaving the glue on the stove.

After lunch, I applied the long, narrow strips which ran along the ridge of the bellows fold, and bending across the corner of the bellows fold. These, then, sat directly on top of the long, narrow leather strip (now worn through in spots) the manufacturer had run around the 6 edges of each bellows fold. I tried the Q-tip smoothing technique on these as well. After I'd done a couple, I tried using my fingers for smoothing and it actually worked much better for me. I'd plunk down the strip, give it literally a second or two to cool a bit and, with thumb and index finger of each hand gently pinching the bellows fold at the corner, I'd slide my hands in opposite directions, away from the corner and along the bellows fold, smoothing the strip along the fold as I went. (The action is just like grasping a folded piece of paper with the index finger and thumb of each hand in the middle of its crease and running the "pinch" from the center of the crease out to the edges. We've all done it a zillion times.) This worked really well, giving a nice tight fit with no wrinkles or air bubbles and forcing the excess glue out. You need to rinse the glue off your fingers after every patch, though.

The glue, to my surprise, dissolved the dye somewhat. I kind of panicked when I saw a green smudge on the bellows paper. But, a Q-tip dipped in warm water removed the glue and the dye that it was carrying very easily, with no residue left on the bellows paper.

After all the corners needing it were patched in this manner, I clamped the concertina in the closed position. First, of course, I put waxed paper between all the folds (per Bob T's suggestion). Bob had actually clamped the bellows in the example shown on his web site after removing both ends of the instrument. I decided to try clamping with the ends still on. I used vice-grip bar clamps, which have nice soft rubber pads on the contact points and which tighten by squeezing a pistol grip. I positioned the clamps so that the edges of the ends, not the fretwork, would be taking the load and tightened the clamps gently. I got the clamps very snug, but not so tight as to risk doing any damage. It was sort of like putting the instrument in a very snug fitting case.

After letting the glue cure over night, I woke up imagining all sorts of horrible things, like the bellows being permanently glued shut, or the glue crumbling off as soon as I moved the bellows. Happily, none of the above occurred. the patches look great. Even with two layers, the leather is so thin that the patches lie nice and flat. The finger-smoothed ones in particular look very even and are hard to notice unless you're looking for them. The glue dries with a nice gloss, like well-finished leather but not overly shiny or plastic looking. (I eventually applied a bit more dye to the patches, which I judged to be a bit too light after full drying. The added dye, although essentially applied to the glue rather than the leather at this stage, did its job and hasn't rubbed off or created other problems.) The bellows were nice and air-tight. The hang-it-from-one-end test produced a pleasingly (and surprisingly) slow rate of bellows expansion. The instrument's reeds responded much faster because bellows travel now caused air to move across the reeds instead of in through the leaky corners. But the instrument felt a bit tight and spongy. It seemed as if it was having a hard time getting air now that the leaks were patched. Well, this Lachenal has leather baffles and they were cut to fit the ends fairly tightly, leaving little room for air to get around them. So, I trimmed the edges of the baffles, and Voila!

It was with some apprehension that I trimmed the baffles because I didn't want to change the tone of the instrument, which is nice and mellow. Also, this was the one modification that was unanticipated and that I hadn't thought through before executing. I'm very satisfied with the results, though. The volume is a bit louder, but not a great deal. And the tone is essentially unchanged, to my ears. The responsiveness is greatly improved. Frankly, I'm somewhat surprised that it worked as well as it did, but the feel of the instrument before trimming the baffles just felt like it was having trouble getting air. Also, a fair amount of dust had gathered at the edge of the baffles, which undoubtedly made matters worse. I initially trimmed very little leather, gave it a try, listened to notes that had more vs less leather above their pads, and then trimmed a bit more -- maybe 1/4 inch around the whole perimeter (except where the baffle was glued; I left those areas undisturbed so as not to alter the fit of the end pieces)

Now this instrument is still a Lachenal with both the virtues and vices that implies. The action is clackity and the feel is still a bit spongy compared to a Dipper or Jeffries. The reeds don't speak as fast as they do on a Dipper or Jeffries, either. But the overall improvement is striking. This instrument plays much faster than before the repair. Ornaments, when the corners were leaking, couldn't be played up to speed because the reeds didn't get enough air to "speak" in the time allotted. Now, no problem. I'll still grab my Dipper when I want to play my fastest, but this old girl does better than she has in a long time.

I was a bit intimidated by this project when I first thought about doing it. Bob Tedrow's excellent advice did a lot to reassure me that I could handle it. (We're very lucky in the squeezebox world to have people like Bob Tedrow who are willing to share there expertise, even when it might mean their losing a profitable repair job to a do-it-yourselfer. Let's not take these people for granted!) I also planned each step of the process before I took action. My assessment is that someone with reasonable dexterity can handle this type of repair without too much trouble. If you're a klutz or incredibly impatient, don't try it. But if you're fairly good with your hands (hey, you can play the concertina, so how bad can you be), you should be okay. Would I do it on a more expensive instrument? Well, if the alternative was a bellows replacement, I'd certainly give it a try because I could always go ahead with the replacement if the results were poor. Having done it once and gotten the hang of it, I think I would do it on a better instrument but I wouldn't recommend making a first attempt on a prize concertina or one with generally good original bellows. You might wind up in worse shape than you started. But I was happy to be able to keep the original bellows on this old Lachenal and the results were highly satisfactory.

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