Gareth Magennis wrote in message
...

"N_Cook" wrote in message
...
2 of the keys are sticking, because the plastic has warped with time or
temperature. Instead of internal dimension of 18.7mm the underside open
width is now about 18.3mm where it abuts the static pillar and rubs
against
it. Any recognised safe method of locally heating or something that will
accurately realign the plastic and retain reformed shape? the throw on
one
side is likely different to the other side so needs taking into account.




I have tried heating deformed keys with a hot air gun, and found it very
difficult. If you are very careful you can just about pull things into a
different shape if it is fouling something, but I found heating of a large
area often reults in the plastic shrinking and the key becoming too short
to
fit/work at all. Different plastics may have different properties
though,
these were old Roland keys no longer available.

Also there seems to be a fine tolerance between getting the plastic
pliable
enough to remould, and so pliable it runs into a goo, which you have no
hope
of moulding back to shape. A temperature controlled oven is probably your
best bet,k and you will need a lot of practice on something disposible
first.



Gareth.




In the next hour I will tackle this. Have something like a 30 amp ceramic
connector block with the metal part removed and hole large enough to take a
brass cased thermometer wedged inside with key laid sideways on a large PTFE
slab. This ceramic small enough to go inside plastic recess and only touch
the one face most deformed. Starting at 60 degrees from hot air I will
increase by 10 deg steps , measuring with Vernier each time.