Stuck Piano Keys – The Dreaded Plastic Piano Parts Experiment

Pianos age very similarly to humans. If you care for your own body properly with exercise, proper food, and dress yourself for the weather, you can still be spry and active into your 80′s and beyond. On the other hand, if you abuse yourself enough, you can be dead from a variety of ailments well before your 40th birthday.

A well built piano that is kept in regulated humidity conditions, played, tuned and maintained regularly, can still function and sound good on it’s 100th birthday. But if you were to leave the same piano out in a garage without climate control and never gave it tuning or maintenance, it would become an unserviceable pile of scrap in just a few decades.

Given all that, a piano built in 1947 should be in pretty good shape. So you might be surprised and alarmed to be playing it one day only to find that the keys begin refusing to come back up after you press them down. One after another they fall and do not rise, until you become afraid to continue playing.

What is happening?

Actually, if this is just happening to you now, you are very fortunate. It should have happened back in the 1980′s. Of course, many pianos go 30 years without being played, so it is relatively common for people to discover this problem quite suddenly now.

What is happening is most likely that you are discovering the hard way that your piano mechanism contains one or more types of experimental plastic parts that were used between 1947 and about 1953.

It all started as what seemed like a perfectly good scheme to save time and money. There are hundreds of small wooden parts in every piano, and carving each one out of wood, even using gang cutters to make batches, is relatively costly. Somebody figured out that these new plastic materials made from soy beans could be squirted into molds and once they set, the plastic had weight, strength, and flexibility characteristics very similar to the wood parts, and the plastic would never warp in changing humidity conditions. This was very exciting news to piano mechanism manufacturers such as Pratt and Read, whose mechanisms (called “actions”) were used in spinet and console sized pianos by dozens of well known companies, and they started widely using the plastic parts, believing that they were not only cheaper, but superior to wood parts.

And they would have been correct. Unfortunately, the formula hadn’t been quite worked out for plastics around 1950, and within 10 to 30 years all of those lovely parts started to crystallize and to give up their moisture into the air. Literally, they began to decompose back into the soy bean power from which they were originally made.

What can you do?

Whether your 1950 era spinet or console piano with plastic parts can be fixed economically or not depends on just how enthusiastic the action manufacturer was about using plastics. Most of the affected pianos are spinet size (the shortest kind of piano) and most of those just had one kind of plastic part, so-called “drop wire elbows”.

Doing detective work

You can determine if your spinet piano has plastic elbows by opening the bottom board. This is the finished kick board that extends vertically facing you from just under the keyboard and has the pedals coming out from the bottom. Case designs vary, but in nearly every case there are one or two springs holding that board in place at the top under the keyboard. Compress that spring with your hand and the board should just slip forward so you can lift it out of the way.

The drop wires start at the ends of the wooden keys and extend down about a foot. They screw into the tops of the elbows which transfer the mechanical motion of the keys to the action. If you have plastic elbows and they are broken or breaking, you will know right away because it will be a mess under there. The yellowed plastic pieces will be fractured into powdery fragments. Literally you will be able to crush the remaining pieces into powder between your fingertips.

At this point, you should consult a qualified and experienced piano technician. You certainly may be able to purchase replacement elbows (made of nylon) for under $100 and install them yourself, but that represents wasted time and money if other parts of the action are also made of the same crumbly plastic.

If you are not an adventurous do-it-yourselfer, your piano technician can replace those elbows, but expect to pay about $200-$300 in labor charges over and above the cost of the parts. If the piano is a family heirloom it may be well worth it to you to invest in preserving it. However it is not likely that a common inexpensive spinet piano made 60 years ago retains enough resale value to justify such repairs.

It should be noted that several Japanese manufacturers began using plastic and nylon piano action parts again starting in the 1970′s. Those parts have shown no sign of premature aging and are still going strong.


Post time: 07-29-2016