-- non-subscriber, please reply to sender and MMD --

In the recent years I found some threads for Lindner pianos in this
forum.  The broken key clips seems a common problem and most Lindners
are now at an age where they are rapidly disintegrating (even without
using them.)

The same with my Lindner of 1966.  With that piano I not only learned
how to play a piano, but also how to tune it, because none of the piano
tuners called by my parents would touch the Lindner when they saw the
plastic action.

After more and more key clips broke it was no more fun to play the
Lindner, and there seems to be no chance to purchase them from any
stock and nobody seems to have invested in injection molding tools for
re-manufacturing the clips.

I first tried using a milling machine to manufacture some clips but the
slot for the leaf spring made too much headache.  After disassembling
the neighbouring keys to build in a spare clip, they also broke while
disassembling; for each key I replaced I had two newly broken keys.
Now I've found an easy and reliable way to weld the clips.

The plastic of the clips seems to be from Nylon material that gets
weakened in the heat.  Welding the clips with hot air is feasible, but
heating time, air flow profile and temperature profile is quite
critical, and ordinary hot air blowers will not do the job.

For hot air, I use a repair station for soldering electronic surface
mount devices manufactured by Weller (Model WQB2000 finepitch/BGA
repair) with a nozzle for SOP8.  A simple fixture makes sure that the
clip has the correct size to fit into the aluminum rail.  Take minimum
of 3 minutes time to heat up, then apply a heat peak to both broken
surfaces, take it out, press it together -- ready.

A similar method to weld PVC tubes is known as "butt sealing/welding
with heat reflectors".  Heating the complete clip to slightly below the
melting point seems also to change the Nylon molecular constitution,
and the welded clip appears flexible as new.

As is well-known, the Lindner guarantee is one month minimum, and
that's bad news for all the piano smashing competitions!

Regards
Juergen Veith
janvi@despammed.com.geentroep [delete ".geentroep" to reply]
http://www.janvi.de/
http://home.t-online.de/home/janvi/