How do you refinish the black keys on a piano?

Answer 1

If the black keys are made of stained wood and the stain is wearing off so that you can see the wood grain below, you can use "key black" for piano sharps. It comes in a little jar and you brush it on. Search the Web for it, a couple of piano parts vendors sell it.

Answer 2

Assuming you are talking about an acoustic (non-electric) piano,

If the manufacturer is still in business, you can order a key (or get a piano technician to order it for you.)

A good piano technician can make a key for you. The key button, keytops and capstans are available at the parts houses. You will need to make the key though and fit these pieces on it. Every key in a piano is different. Even an exact replacement will have to be fitted.

A key can be made from a fine grain wood that is not susceptible to dimensional changes due to changes in moisture. A good wood would be basswood. I have made keys but it is a lot of work to do a good job. I would charge about $200 to make a key from scratch.

If the key is broken and you have the pieces, it can also be easily repaired. There are two common ways and sometimes, I have done both to the same key. They usually break at the center pin. You can glue the pieces back to gether with wood glue and then reinforce on both sides with pieces of wood veneer. You can also glue it together then drill and place a wood dowel across the break, then redrill the hole if necessary. A good repair is the way to go if you have the key. A repair would cost about $75 or maybe less.

You need to go to PTG.org and find a piano technician in your area.