[pianotech] Polyester Repair problem

[John Formsma]

Ruth Phillips sells a product for this problem. (www.alliedpiano.com)  It's
acrylic enamel, used because of thin Yamaha finishes and the problems that
develop as a result. You may brush it on, or spray for better results. I
brushed on three coats, then sanded and polished like you would polyester.
It turned out OK, keeping in mind that it was a REPAIR. If I had had proper
refinishing stuff, like a small sprayer and electric buffer, it would have
been nearly invisible. It buffs to a shine very nearly equivalent to poly.
You could always try the spot repair first. If that didn't work, it wouldn't
take too much time to spray the entire fallboard and polish.  If you wanted
to get it right the first time, you could plan to do the entire fallboard.
 It is a mechanical bond, so you must first scuff up the existing finish
with 600 or so grit.

Ruth was very helpful. This was my first (and only so far) poly repair, and
it turned into a nightmare because I sanded through the thin layer.  Great
learning experience -- negative income, though.  Because of carelessness, I
had chipped the bottom of the fallboard with a hammer screw when removing
the action.  :-(

--
JF

On Thu, Apr 23, 2009 at 10:41 PM, Chuck Behm <behmpiano at gmail.com> wrote:

> Dear List - In repairing a chip on the front of a Yamaha fallboard using
> the Schaff polyester repair kit, I got too ambitious with the 500 grit
> wet/dry paper during the leveling out step and rubbed through the black in a
> spot next to the fill. Since I'm only at 500 grit, I'm sure the problem will
> worsen as I go through the rest of the grits. When I realized what had
> happened, I decided I needed to stop right there until I was sure of what
> steps I should be taking next.
> I'm clearly out of my element here, and need advise. Do I need to spray
> over  the entire front of the fallboard, or just the side on which the
> repair is located and feather it out,  or is a simple touching up of the
> rub-through possible? What product or product and techniques would work the
> best? I have a good compressor and spray equipment, if that would be needed.
> My only concern is that the completed job looks right when it's done.
>  Rarely does anything less than 75 years old come into our shop, so working
> with hi-gloss ebony is something I hardly ever do. Words of wisdom from
> someone in the know would be highly appreciated.   Thanks in advance, Chuck
>
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