"Gluing on" plastic keytops

[Billbrpt@AOL.COM]

In a message dated 8/4/99 4:06:00 PM Pacific Daylight Time, you write:

<< A lurker I am.  
 
 Here is my $.02.  This rookie associate has recently stumbled onto a glue, 
 that does a superb job on plastic keytop replacements.  Maybe others have 
 already been using this, I don't know, but here goes. 
 
 Elmer's makes a premium quality neoprene based contact cement, that is easy 
 to work with.  I have used it on 3 sets of keys without any 
problems...(snip) >>

I don't mean to discourage you in any way and am pleased to know about the 
easily available and good glue you have found but there is more to replacing 
keytops than the gluing of new material procedure alone.

When I read your post I think of my own experience, a lesson learned the hard 
way many times over.  If you regularly do what I am about to make a point of, 
then I apologize in advance for assuming that these very important items are 
being overlooked.

Many people, technicians and piano owners alike look at their old, irregular 
keyboard with ivory pieces missing and see those bright, shiny new preshaped, 
molded keytops and assume that it would be a simple task to "recap" the old 
keys.  But there are two dimensional differences between the preshaped 
keytops and the original ivory which also must be accounted for in order to 
have a keyboard that is playable when you finish.

The new plastic is thicker than the old ivory so just gluing on a new plastic 
keytop without precision planing down of the key will change the key's 
dimension.  The sharps will now "bury" themselves between the white keys.  If 
you decide to do this anyway or encounter another keyboard done this way 
without compensation, you can compromise by altering the plane of the sharps. 
 Using a medium to thick card punching and/or smaller shims as needed, you 
set the key height of the sharp sufficiently above the plane of the new white 
keytops.  You also must compensate with card punchings under the front rail 
of the sharps.

Don't overdo this either.  If you sharps are too high, they may not fit below 
the tops of the balance rail pins and may also present a fitting problem with 
the fallboard and or key upstop rail.  So, don't go by arbitrary specs such 
as 1/2" for sharp height.  Find out the least amount you can raise it and 
still have a full range of motion and adequate aftertouch for the sharp key 
with it still bottoming out slightly above the plane of the new white keytops.

The other important point is that the molded plastic keytop is usually wider 
than the original key.  Simply gluing on the keytop without trimming the 
sides leaves a kind of ridge on one side of the key or the other that is very 
irritating to the pianist.  Sometimes, the pianist will catch a finger in 
that ridge which will interfere with normal playing.  Also, the narrow part 
of the keytop may greatly overlap the wooden key and cause rubbing, knocking 
or clicking of the keytop against the sharp, especially if the key bushings 
are not up to good specs (a very common condition).

If the gluing job starts failing after a few years, the whole thing becomes a 
small tragedy.  However, being able to make a spot repair of a loose or 
damaged keytop, or to glue back on a few ivories for a customer who has an 
older piano that is otherwise reasonable is a good and proper thing to know 
how to do.

I encourage you to pursue the keytop replacement market however because I 
know there is lots of needed work.  Getting the right planing equipment and 
learning to trim with nice regular and square sides and corners will be a 
satisfying occupation for you.  Also getting and learning to use keybushing 
equipment such as that which Bill Spurlock RPT has developed and marketed can 
compliment the key covering work you do and make your customers really 
pleased and you proud of your work.

Good luck,

Bill Bremmer RPT