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Yamha U3 polyester or polyurethane

Posted By: AGiorgianni

Yamha U3 polyester or polyurethane - 08/15/19 05:12 PM

Hello All

I have a Yamaha U3AR with a high-gloss finish that I purchased new in 1987, I think. (It's a 1987 serial number in the range of 4334800. Does anyone know if this is polyester or polyurethane? Or is there any way to tell?

Many thanks.
Anthony Giorgianni
Posted By: P W Grey

Re: Yamha U3 polyester or polyurethane - 08/15/19 06:46 PM

Doubtlessly polyester. Virtually all high gloss pianos are polyester.

Pwg
Posted By: tunerman

Re: Yamha U3 polyester or polyurethane - 08/15/19 08:12 PM

All- Sometimes these were polyurethane with lacquer sprayed over and polished to high gloss. I learned this to my chagrin many years ago after a large in shop touch up when I burned through the lacquer to the polyurethane that will not take a polish. Had to respray the whole side and re-polish., So, if the finish reacts to lacquer thinner , which polyester won't, then it may be polyurethane underneath. Not sure of the dates of this transition, but the 80's are a good possibility.

YMMV

David Brown RPT
Garland TX
Posted By: P W Grey

Re: Yamha U3 polyester or polyurethane - 08/16/19 12:34 AM

Anthony,

Pray tell, why do you ask? Just wondering.

Pwg
Posted By: Pro-TAC

Re: Yamha U3 polyester or polyurethane - 08/16/19 03:28 AM

Yamaha has adopted all polyester paint since 1988.
U3AR...Some parts may be lacquered..(Side panel, arm ,toe rail.)
Upper panel end block, base molding=AS raisin or lacquered.
Toe block,leg,keybed =AS resin.
Other models have used UV coat for a while time。

Let's check before repairing.

If the sanding powder is,,
Bitter smell= polyester.
Sweet smell=AS resin.

Black=lacquer.
White gray=polyester.
Blue gray=AS resin.

See through a flashlight.
Purple=polyester.
Blue=AS resin.
Black=lacquer.

For your information.
https://photos.app.goo.gl/Y9b8EfqhXsBTJhRE6
Posted By: Rick_Parks

Re: Yamha U3 polyester or polyurethane - 08/16/19 07:07 PM

get s small can of lacquer thinner and test somewhere out of sight--- thinner won't remove polyester.
Polyester tends to look very thick and does not take a sharp edge well.

Are you refinishing? Repairing?
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