I went to my customer's house prepared to tune her piano. She had warned me that some notes weren't working, usually not a big deal. As soon as I opened the piano and looked inside, I could see the problem. There were shards of a yellowish white plastic all over the place. Oh no, plastic action parts!
To be fair, there's nothing wrong with plastic action parts if they're made correctly - the same can be said of wooden parts. This piano, a beautiful console made in 1957, had action parts made of PVC, and I'm sure the parts worked well for a time. Now the plastic had begun to disintegrate, and the parts would have to be replaced.
PVC, polyvinyl chloride, is usually referred to simply as vinyl. It is one of the most widely used plastics. It can be molded into things like pipes, it can be made into shiny cloth, and it can be bonded to fabric for use in upholstery, mimicking leather. The properties of vinyl chloride had been investigated as early as the late 19th century, but it wasn't until the 1930's that a commercially viable plastic was developed. PVC is quite rigid and brittle, and requires the addition of various plasticizers and stabilizers. Vinyl combined with cellulose acetate (another plastic) as a plasticizer is what replaced lacquer for making phonograph records, starting in the 40's. Vinyl without plasticizers is what is molded into rigid shapes, like pipes for plumbing, and siding and flooring for houses.
Rigid PVC should have been perfect for replacing wooden parts in a piano action. The plastic parts were molded in the same shape as the wooden ones, and installed the same way. The most common plastic parts were flanges, which are the hinged ends of many action parts and are attached with screws to various rails. In some actions, backchecks, jacks, and damper levers were also made of PVC. The only parts that were not made of plastic were the parts that are glued to each other. PVC parts can be bonded together (using the solvent methylethylketone, or MEK, often called PVC glue), but I guess this was not viable for the action manufacturers. I did see a Lindner piano, made in Ireland, probably in the 60's, whose action was entirely of plastic. Even the keys were plastic, made of sheets of PVC glued into long hollow rectangles.
The problem with PVC, as with many other plastics, is outgassing. The various additives that give vinyl its different characteristics slowly evaporate out of the plastic. Over time, some plastic becomes more brittle, or shrinks, or becomes discolored, or, in the case of PVC, spontaneously disintegrates. The technology behind the additives is almost more important than the technology behind the plastic resin itself. When PVC was used for piano actions, the technology for stabilizing rigid PVC must have been in its infancy. It was not foreseen that the outgassing would proceed so quickly, that the actions would start to fall apart in a couple of decades. Modern PVC could be used with no problem, but now the piano industry won't go anywhere near it, and modern plastic action parts are made of other plastics.
The solution is simple, but costly. The parts must be replaced. PVC spinet elbows are replaced with acrylic ones, but other parts are replaced with wooden ones. The parts are readily available because of the demand. Sometimes not all of the PVC is falling apart, so apparently the outgassing varies from batch to batch. For instance, in the case of the console I'm working on, the jacks and backchecks are completely shot, they crumble at a touch, but the hammer flanges and damper levers are fine. They're not the least bit brittle. I won't replace them for now, but I have warned the owner about the possible need for replacement in the future.
There has been one other use of vinyl in pianos. Some of the more crazy and delightful console and spinet case designs from the 40's and 50's used vinyl upholstery fabric in addition to the more traditional wooden veneer. It's found on the sides and top, and Wurlitzer was the main culprit. The vinyl is usually embossed with the classic leather grain, and my favorite example used a white-with-brown-spots cowhide pattern.
Vinyl imitation leather has also been used to replace the leather on the ends of bridle straps, the straps that connect upright hammers to the wippens. Over time, the leather disintegrates (not to mention the strap itself), but the vinyl holds up for much longer. The only disadvantage is that it stiffens up over time and can rattle against the bridle wire. It also becomes harder to remove from the wire. I'll have more to say about the use of artificial leather and suede in pianos in a later post.
Related website:
The Plastics Historical Society
Showing posts with label Plastic in Pianos. Show all posts
Showing posts with label Plastic in Pianos. Show all posts
Monday, May 25, 2009
Sunday, May 24, 2009
The Plastic Piano - Introduction
The piano manufacturing industry is quite progressive, eager to embrace any new material or manufacturing process. The goal is usually to save money, to keep the price of a new piano down, but sometimes an innovation can add value to a piano, improve it in some way that can be reflected in a higher price or a more competitive product.
Plastic has always been one of those new materials, ever since the industry started using celluloid in the 1870's. The chemistry behind various plastics was not well understood then, and innovation relied on experimentation, sometimes with terrible results. There were three prominent plastics disasters in piano manufacturing history. The first was with PVC, used in the 1940's and 50's to make action parts. Molded PVC parts were successful at first, but as the plastic aged, it tended to spontaneously disintegrate. This effect would take several decades to manifest, so that left a lot of time to build plenty of pianos with PVC action parts, all falling apart now.
The second was with Steinway's Teflon action center bushings. These were tiny inserts made of Teflon, hundreds per piano, that Steinway used in the 70's. They worked well at first, but after a few years they became quite noisy and needed replacing. Steinway tried again with a different size insert, and they did work better, but Steinway eventually abandoned the effort and went back to felt bushings.
The third was less disastrous, but still annoying, and it involved Yamaha's Ivorite, a plastic for keytops developed in the 80's. This plastic is porous, and thus does not feel as slick and slippery as other plastic keytops. It soon became evident that it was a bit too porous. As the plastic soaked up finger oils, it stained in a way that looked, frankly, disgusting. Yamaha reformulated the plastic, and offered to replace all the unsightly keyboards. Now the Ivorite works fine.
These negative experiences with plastic has made the industry wary of introducing more plastic into pianos. Pianos are sold, after all, on their 19th century charm, and nothing screams "modern" (not to mention "cheap") like plastic. The word itself is avoided like the plague, and replaced with phrases like "thermoset composite material," or trademarks like "Ivorite." Often plastic is introduced in small ways, in parts of the piano not visible, or crucial to its function as an instrument. When plastic is obviously employed in a significant way, a whole public-relations blitz is rolled out to carefully explain how the new plastic parts are a huge improvement over the old parts, whether or not that is true. When Kawai used its first plastic action part in the 90's, a plastic jack, I was asked by the local dealer to sign a statement in support that would be used for advertising. I was more than happy to help until I read the statement. It was asking me to agree that the new plastic part was superior to the old wooden part, which was ridiculous, and not true in this case. I refused, much to the dealer's anger.
Nothing has changed the piano in the 20th century as much as plastic has, and I am going to post a number of articles about the plastics used in pianos, all under this heading of The Plastic Piano. I'll keep the series as a permanent link in the sidebar. Glues and wood finishes are forms of plastic, and I will include them.
Modern plastics, and modern chemistry, is a whole different world from eighty years ago, and I am glad to report that current uses of plastic are much better engineered. Some of these parts are not only cheaper, but they really are an improvement over the old parts, taking advantage of the qualities of different plastics as materials. Manufacturers are beginning to be less furtive, less scared of the older disasters. Having tiptoed through the plastics revolution of the late 20th century, maybe the industry can enter the 21st more boldly.
Related website:
The Plastics Historical Society
Plastic has always been one of those new materials, ever since the industry started using celluloid in the 1870's. The chemistry behind various plastics was not well understood then, and innovation relied on experimentation, sometimes with terrible results. There were three prominent plastics disasters in piano manufacturing history. The first was with PVC, used in the 1940's and 50's to make action parts. Molded PVC parts were successful at first, but as the plastic aged, it tended to spontaneously disintegrate. This effect would take several decades to manifest, so that left a lot of time to build plenty of pianos with PVC action parts, all falling apart now.
The second was with Steinway's Teflon action center bushings. These were tiny inserts made of Teflon, hundreds per piano, that Steinway used in the 70's. They worked well at first, but after a few years they became quite noisy and needed replacing. Steinway tried again with a different size insert, and they did work better, but Steinway eventually abandoned the effort and went back to felt bushings.
The third was less disastrous, but still annoying, and it involved Yamaha's Ivorite, a plastic for keytops developed in the 80's. This plastic is porous, and thus does not feel as slick and slippery as other plastic keytops. It soon became evident that it was a bit too porous. As the plastic soaked up finger oils, it stained in a way that looked, frankly, disgusting. Yamaha reformulated the plastic, and offered to replace all the unsightly keyboards. Now the Ivorite works fine.
These negative experiences with plastic has made the industry wary of introducing more plastic into pianos. Pianos are sold, after all, on their 19th century charm, and nothing screams "modern" (not to mention "cheap") like plastic. The word itself is avoided like the plague, and replaced with phrases like "thermoset composite material," or trademarks like "Ivorite." Often plastic is introduced in small ways, in parts of the piano not visible, or crucial to its function as an instrument. When plastic is obviously employed in a significant way, a whole public-relations blitz is rolled out to carefully explain how the new plastic parts are a huge improvement over the old parts, whether or not that is true. When Kawai used its first plastic action part in the 90's, a plastic jack, I was asked by the local dealer to sign a statement in support that would be used for advertising. I was more than happy to help until I read the statement. It was asking me to agree that the new plastic part was superior to the old wooden part, which was ridiculous, and not true in this case. I refused, much to the dealer's anger.
Nothing has changed the piano in the 20th century as much as plastic has, and I am going to post a number of articles about the plastics used in pianos, all under this heading of The Plastic Piano. I'll keep the series as a permanent link in the sidebar. Glues and wood finishes are forms of plastic, and I will include them.
Modern plastics, and modern chemistry, is a whole different world from eighty years ago, and I am glad to report that current uses of plastic are much better engineered. Some of these parts are not only cheaper, but they really are an improvement over the old parts, taking advantage of the qualities of different plastics as materials. Manufacturers are beginning to be less furtive, less scared of the older disasters. Having tiptoed through the plastics revolution of the late 20th century, maybe the industry can enter the 21st more boldly.
Related website:
The Plastics Historical Society
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