Pianotech

  • 1.  Refinishing plate that has polyurethane finish

    Registered Piano Technician
    Posted 03-31-2019 00:41
    I have a plate to finish that has a polyurethane clear coat over some sort of metal powder undercoat over some sort of grey filler coat.

    My standard plate finish is bronze powder in bronzing lacquer, two coats sand between, then wet sand 1200 grit, (agraffes out) and thin clear lacquer top coat over agraffes and all.

    I found alcohol will soften the urethane so I can sort of scrape it away but that seem much to laborious. Sanding would take forever since the top clear coat is rather thick. I don't wnat to strip it because that risks removing the filler coat.

    Anybody have any experience?

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    Edward McMorrow
    Edmonds WA
    425-299-3431
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  • 2.  RE: Refinishing plate that has polyurethane finish

    Posted 03-31-2019 01:01
    My go to is Duplicolor primer available from NAPA.  Spray that over whatever, and if there is no reaction, then you can mix the bronzing powder in the duplicolor clear coat and follow your regular procedure. So far I have not seen it not stick to anything.
    -chris

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    Troubles are Bubbles, and they just float away.
    chernobieffpiano.com
    grandpianoman@protonmail.com
    Knoxville, TN
    865-986-7720
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    Original Message


  • 3.  RE: Refinishing plate that has polyurethane finish

    Posted 03-31-2019 09:18
    Ed,

    You might consider the water based system I wrote about in the journal a little while ago. The STIX primer, which is available at most any hardware store, being a urethane acrylic (water based) sticks aggressively to all kinds of substrates. I have had no compatibility issues since I started on this finish schedule, and it sticks tenaciously.  Just finish over whatever it is without stripping...stripping a plate...ughh...what a thought.

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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    Original Message


  • 4.  RE: Refinishing plate that has polyurethane finish

    Posted 04-01-2019 06:55
    Bring it over to your local powder coating shop. They'll sand blast it to the bare metal and put on a superb base coat for you that's easy to work with, for a very reasonable cost.  It will take a little more bondo work to get a beautiful smooth surface but the results are worth it.

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    Philip Stewart, RPT
    NJ Piano Service
    609-774-7571
    www.njpianoservice.com
    njpianoservice@gmail.com
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    Original Message


  • 5.  RE: Refinishing plate that has polyurethane finish

    Posted 04-01-2019 02:51
    After power washing, spray it with sanding liquid (also called sander deglosser). I've used it on dozens of plates before spraying DuPont Chroma system. Especially good for around the lettering.

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    Glen Hart
    Grand Junction CO
    970-434-5558
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    Original Message