Pianos frequently make use of touchweights to improve balance and action.

Traditionally these weights are made of lead (Pb) — a toxic metal.

Touchweight is the amount of pressure required to depress a key on a piano.

Touchweights — also known as keyleads — are used to balance piano keys so that the required pressure is consistent from key to key.

This first picture shows keyleads in one key of an older Steinway grand piano.

Keyleads 1875 Steinway close-up

This picture shows several keys and numerous keyleads on the same piano. Each keylead in this picture represents approximately 15 grams of Pb.

Keyleads 1875 Steinway long view

There may also be keyleads at the opposite end of a piano's mechanism. In a standard 88-key piano the amount of Pb on board is substantial. The piano shown above easily contains 15 pounds (7 kg) of Pb.

This picture shows the key mechanism in a newer piano. There are fewer keyleads in this example and they are smaller.

Piano action highlights location of lead

The size, number, and position of keyleads is variable between manufacturers, models, and even individual pianos. Frequently keyleads are pre-installed by the piano manufacturer, but these can be modified later by technicians in the field.

Generally speaking, better quality pianos will have better touchweight treatments — and more Pb.

Unless you are a technician or do your own restorative work, you generally won't come into direct contact with embedded keyleads.

For piano musicians and owners, the question is, "How much Pb exposure comes from Pb dust and oxidation as the piano is played and it ages?"

Unfortunately, there is simply no clear answer. There has been no research done to quantify the Pb output of pianos.

To do such research requires time, money, expertise, commitment — and demand. So far those circumstances have not come together.

One piano expert relayed this anecdote.

"A technician was in the shop doing touchweight rework with Pb — day after day after day. She became pregnant. Her husband found out she was working with Pb and went ballistic. She got a blood test and it came back 'normal', so she went back to work in the shop..."

Unfortunately, "normal" doesn't mean "safe" because blood tests don't adequately reveal toxic metal burden.

Even for piano builders, technicians and restorers, the level of occupational risk is poorly quantified.

Obviously there is more than just casual risk — there is no known safe level for lead exposure of any kind.

In the absence of verifiable data, the Precautionary Principle should prevail. What follows is basic information to help you act thoughtfully.

Grand pianos almost certainly have Pb keyleads (sometimes called keyweights).

Upright pianos typically do not, *BUT*...

... the only way to know for certain is by close inspection.

In uprights, the keyleads are often located further back on the keys and may not be visible simply by depressing the keys and looking at the sides. It may be necessary to partially disassemble the piano to be sure.

Pb weights may also be used for balance in the hammer assemblies and dampers. This might only be evident to a technician.

Grand piano action highlights location of lead weights

Upright piano action highlights location of lead weights

Keyleads have been used in touchweight design for at least a hundred years. It is possible they are in any piano, of any age, by any maker. You can only be certain by checking.

Purity of the keylead has a big influence on the risk of Pb exposure.

Very pure Pb tends to oxidize slowly. Less dust is shed.

Note: Pb cast into weights must be combined with some other metal to lower the casting temperature and reduce viscosity. Tin (Sn) is often used for this purpose, and “pure Pb” often refers to a Pb+Sn alloy. Antimony (Sb) is often added as well to improve hardness.

On the other hand, Pb from scrap and other inexpensive sources can contain impurities that allow it to oxidize more quickly. This increases the likelihood of exposure.

Typically the oxidized material will have a chalky white or gray appearance, but impurities may cause other colors to appear. This picture shows the contrast in appearance between a heavily oxidized lead bullet and its iron case.

contrast between oxidized lead bullet and iron case

One expert piano technician says he's seen 100-year-old keyleads that look brand new. He's also seen relatively fresh keyleads that have suffered rapid deterioration.

Climate plays a role in the rate of oxidation and exposure.

Elevated humidity can cause the wood in piano keys to swell. Adjacent keyleads can begin rubbing together when the piano is played. This friction increases the amount of Pb dust generated.

One technician cited a piano in Hawaii with keyleads that were rapidly oxidized by the ocean air.

If you are ordering a brand new piano, ask whether keyweights can be fitted with a substitute metal like copper, iron, or brass. Baldwin has been mentioned as a company able to accommodate such a request.

Some European piano makers may already be using safer metals in pianos built within recent years — ask for details regarding any specific piano.

Many pianos are manufactured in China where the use of Pb keyweights is still widespread.

For existing pianos, qualified technicians may be able to rework keys to help players and owners reduce long-term Pb exposure.

Pb keyleads can be sealed in place with an epoxy. Durability depends on the type of epoxy used and the environment.

Pb keyleads can be removed and replaced with a safer metal. This is a messier task and may release a lot of Pb in the process.

Original keys can be completely replaced with new non-weighted keys, or with new keys that use a safer metal.

For better pianos and/or better pianists, it may be worthwhile to install a Magnetically Balanced Action (MBA). This enables a precisely balanced action across all keys that can be preferentially adjusted for the life of the piano.

After any of these services the keys need to be re-balanced for proper touchweight.

These rework services involve the handling of Pb and exposure to its dust. For safety and efficacy the work should be done in an appropriately equipped shop.

But be aware that even the best technicians are not trained in the art of decontaminating pianos before returning them. Awareness about piano Pb in the context of overall toxic body burden is just beginning to emerge.

Be sure to specify what metal will replace Pb. Some technicians use bismuth (Bi) because it is dense like Pb. Unfortunately, Bi is toxic, too.

The expense involved with performing these kinds of services is significant. A piano can have 6,000 to 10,000 parts. Disassembly to recondition a target part may involve the reconditioning or replacement of associated parts. The piano's condition, location, and other factors must all be considered.

Certified piano technicians can be found through The Piano Technicians Guild. Click on their 'Find a Technician' link to get a list of qualified technicians in your area.

Gratitude goes to members of The Piano Technicians Guild and to PianoFinders for providing much of this information and for permission to share it.