[pianotech] Abrasions in polyester finish

[paul bruesch]

Ron, Thank you!
To reiterate though, for this particular piano, my main interest is a quick
job to eliminate as much of the white as possible (without breaking through
to the substrate!)
This information will be of benefit for other, more detailed work.
Paul

On Wed, Sep 7, 2011 at 7:38 PM, Overs Pianos <sec at overspianos.com.au> wrote:

> Paul,
>
> If the scratch is white, but is shallow enough not to go right through to
> the substrate, it can be cut out with a hard block (which has been sanded
> flat), going through the grades from the coarsest which is required, to 1200
> grit for machine buffing and polishing, or 2000 grit for hand finishing.
>
> The most common problem I see with poly repairs which have been cut and
> polished is that the damaged area often is sanded without making it a wider
> blend with original surface level. This results in a depression at the
> repaired area which can look quite unsightly, particularly if the final
> finish quality is good. This is why I don't use a cork bock or other easily
> deformed block for the sanding grades prior to the final grade. It is OK to
> use a cork block for the final grade, but it should be used wet and without
> too much pressure. The cork block should also be cut flat each time it is
> used. This will only take a couple of seconds if the block is close to flat,
> as it should be if it is touched up regularly.
>
> A 'hand glaze' won't have enough cut to use straight after the 1200 grit.
> You'll need a heavy-cut compound, to be followed by an intermediate cut,
> then by your hand glaze. There are so many different makers of cutting
> compounds out there, but they are starting to publish their cut rate in
> their promotional literature, which finally is giving us real information as
> to the relative cut rate and courseness of the various products. I still use
> a stitched mop for the first two machine cuts. We currently use three grades
> of abrasive compounds from the 1200 final sanding to the final finish.
>
> Menzerna Power Gloss is a very agressive cut which takes out 1200 marks in
> short order, and will even cut out 600 marks if you haven't been paying
> attention during the cut stages. Megiars Diamond Cut Compound 2.0 is
> economical to buy by the US gallon, and it cuts out the Menzerna Marks
> easily while leaving the surface very nicely prepared for the final cut with
> a foam wheel using 3M Foam Polishing Pad Glaze (05995). Getting a good
> finish is something which takes experience and developed skill, but its not
> something to be frightened of, and can be a good skill to have to complement
> your other piano work.
>
> Regards,
> Ron O.
>
>
>
>  A new client I tuned for yesterday has a small YC grand. I noticed
>> light/white-colored abrasions on the treble side of the black-polish case,
>> right on the outside curve.
>>
>> When I asked her about how they came to be, she told me that they'd had it
>> moved many times, so when they wanted it moved one MORE time, they decided
>> to do it themselves ("It looks so easy when the pros do it"), and dragged it
>> on a "soft carpet, only soft carpet".
>>
>> She's the first client I've ever known that had her own bottle of Cory
>> High Gloss Finish polish (which I always bring, too) though the piano was
>> quite dusty and well-smudged. As I cleaned, dusted, vacuumed, and polished
>> with the Cory, I noticed that the abrasions seemed to be slightly reduced in
>> intensity.
>>
>> It just occurred to me now that perhaps this could be buffed out? I didn't
>> consider that possibility and took no photos while I was there. I just
>> called the owner to ask if she could take a photo or two, but she cannot.
>>
>> Was the apparent reduction in abrasion likely my imagination? Or would it
>> be worthwhile to try something with a very mild abrasive? I'm thinking
>> something like "3M Imperial Hand Glaze 05990"
>>
>> And yeah, I know a photo would probably help a lot... sorry!
>>
>> Paul Bruesch
>> Stillwater, MN
>>
>
>
> --
> OVERS PIANOS - SYDNEY
>   Grand Piano Manufacturers
> _______________________
>
> Web http://overspianos.com.au
> mailto:ron at overspianos.com.au
> _______________________
>
> A web page with images of recent work and almost-audio-CD quality mp3 sound
> files of the Overs piano can be found at;
> http://overspianos.com.au/**more_info.htm<http://overspianos.com.au/more_info.htm>
>
> So put on your headphones, plug them into your freshly restarted computer
> and sit back to over 20 minutes of pure piano.
>  _______________________
>
>
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