On Sun, 12 Aug 2007 21:51:41 GMT, "George"
wrote:

my clarinet needs polishing up as its gone dull,dunno how old it is?


If it's a synthetic body it won't be Bakelite....it'll be Ebonite.
If it's any more recent than about 1960 it could well be one of many
other hard rubber or plastic compounds...though these tend not to
dull.

As ebonite ages it breaks down at the surface and typically goes a
dull brown/green colour.
It's possible to cut the surface back to reveal the original colour,
but it's a lot of hard work - and because the breakdown is an
irreversible chemical one the new finish seldom lasts very long.
Exposure to light ( particularly sunlight ), air pollution, acidic
compounds and heat ( including warm water ) will turn the surface
green again. All of those things happen if you simply take the
instrument out of the case and handle it.

Cutting back the surface is best done with a buffing mop and bar of
medium grit soap ( Tripoli..or brown soap ) - but extreme care is
needed otherwise the friction of the wheel on the job will turn the
ebonite green again.

Polishing fluids aren't recommended - the stuff gets into the pores,
and the fluids themselves often react with the ebonite. More often
than not the polish residues turn white when they dry, then people
attempt to wash them off in warm water....and it's back to square one.

Without a buffing machine, the best method of cutting back the finish
is 0000 gauge wire wool. The drawback is that it leaves a matt finish
- but then most true ebonite clarinets never had a completely glossy
finish anyway. The wire wool must be used dry.

It could, of course, be made of wood - typically a blackwood, though
early 20th century clarinets were often made from Cocobolo.
Best way to test without the benefit of an experienced eye is to shave
a *very* fine slice off one of the tenon joints ( the sticky-out bit
with a band of cork on, on one of the ends of the joints... ) then
burn the shaving and take a whiff of the fumes.
If it smells like satan farting in a kebab shop - it's ebonite.

Professionally speaking, it's not worth it. If it's a collectable make
( Conn, Buescher...) your work will devalue it.


Regards,



--
Stephen Howard - Woodwind repairs & period restorations
http://www.shwoodwind.co.uk
Emails to: showard{who is at}shwoodwind{dot}co{dot}uk