Finishing ivories

[David Love]

Sanding old ivory is tricky and depends how much material you have to start
with.  It is best to sand by laying a sheet of paper to a very flat surface
such as a thick piece of glass, and then laying the key on the paper and
sanding by moving the key back and forth.  However, if the ivory is not
thick enough you can create problems.  Also, if the old ivory is cupped
from wear you will probably have to take off too much material this way. 
Us a hard sanding block over the joint then to smooth this area.  To make
the joint less visible you need to be sure the upper surface contacts
before the lower surface which means the contacting edges of the head and
tail are beveled back by 1 degree.  Keep the glue away from the joing by 1
mm.  If the glue squeezes into the joint you will be more able to see the
line.  A clamping device that pushes the head back against the tail, after
the tail is laid down and clamped, will help.  

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: Stéphane Collin <collin.s@skynet.be>
> To: Pianotech <pianotech@ptg.org>
> Date: 5/17/2004 10:20:51 AM
> Subject: Finishing ivories
>
> Dear list,
>
> I am pretty proud of my latest ivory tops cleaning, bleaching, gluing, 
> shaping and buffing job.  Though, I would like to get closer to expert 
> professionnal result.  At the end, the ivories look quite nice, but 
> there are still some scratches visible (not tangible) in it.  Who could 
> help me imporve my process ?  Here it is :
>
> I unglue the existing ivories with a damp cloth, an iron and a sharp 
> knife.  Works fine, without damaging the wood.
> I put the ivories in boiling water with detergent, to get them rid of 
> glue and other dirtynesses.  Works very good, as long as you control the 
> timing.
> I rince them and dry them in an oven at medium low temperature, watching 
> for the moment they start to curl, and then turn them around, and watch 
> again until the moment they are flat again.  Great.
> I put them under an UV neon light and spray some 30% oxygenated water on 
> them, now and then.  After one day and one night, they look white enough 
> for me.
> I glue them back on the keys with cement and solid copper clamps 
> (difficult : the ivories tend to move on the key when pressed in the 
> clamps, even when and the ivories and the wood is carved).
> I shape the length and the curves with a 400 grit sandpaper glued to a 
> straight piece of wood.  This works fine.
> I sand the ivory surface with 240 grit paper, to try and make a good 
> level joint between the two pieces of ivory on the key.  This doesn't 
> work well : you can still feel the joint even after huge sanding.  I 
> stop sanding before I get the feeling that I am going too far, that is, 
> removing too much stuff and gettind clearly destructive.  Yet you still 
> feel the joint.  No good.  (Ideas ?)
> I sand down the grits until 800.  Here: ok but ivory surface seems to 
> tend not to be perfectly plane, so not all the surface gets sanded.  
> Again, should I sand that much that everything is plane ?
> I then use a cotton buffing wheel with finishing composition, at fairly 
> high speed.  This gives some gloss, but there appear and remain 
> scratches that you can hardly feel but clearly see when looking at the 
> keys in front of daylight.
> I feel my results are good but inferior to dedicated professionnal 
> ones.  Is there a chance that I could improve my skill on this ?
>
> Thanks for any idea.
>
> Stéphane Collin.
>
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