[pianotech] Soundboard Lacquer Finish

[Nick Gravagne]

William,

 

Do you have a paste polish to recommend? I appreciate the tip RE electric
polishers. Sanding to higher grits, followed by a polish sounds like the
plan for now. 

 

I have heard some talk RE polyurethane, but for some reason I can't seem to
get with it; probably too much experience with lacquer, and the boards sound
good, not weighed down. But I am willing to be convinced otherwise. Are
there advantages to poly over lacquer?

 

I am spraying on the lacquer, but brushing on the shellac. I use a Mohawk
reducer (thanks to M. Spreeman) in the lacquer along with the lacquer
thinner and the flow out seems pretty nice; no sandy or matted looking
sections.

 

Thanks William.

 

Nick Gravagne, RPT

Piano Technicians Guild

Member Society Manufacturing Engineers

Voice Mail 928-476-4143

 

  _____  

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of William Monroe
Sent: Thursday, March 19, 2009 6:57 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Soundboard Lacquer Finish

 

Nick,

I don't know that I can contribute much to your schedule, but I'd recommend
against any electric polishers on lacquer.  Far too easy to burn/melt NC
Lacquer.  If you want to polish, either french polish (sounds like you don't
need that since you're not going for super high gloss) or just follow a
typical sanding/polishing schedule.  Sand to p800 or p1200 or whatever you
desire and then rub with a polish of your choice.  Probably pumice and
rottenstone are out of vogue, but if you like the results and are familiar
with the protocal, why not use it?

For many folks, shellac/lacquer is out of vogue too, in favor of
polyurethane.

Are you spraying or brushing your lacquer?

William R. Monroe

www.a440piano.net

Hello All,

 

Seeing Dale's B board prompted me to get your take on a finishing schedule
for lacquer on soundboards (Sitka, if it matters). Currently finishing a M&H
BB board, which has not yet been installed on rim.

 

Thus far:

 

Board has been sanded to 220 grit, sealed and colored with shellac flakes
and lacquer thinner (tawny - amber look), raised grain scrubbed with pads,
two wet coats of high solids lacquer sanding sealer wet-sanded out, one
heavy wet coat of high solids semi-gloss lacquer (amber) wet sanded to 400
grit and steel-wooled to even out. Will go higher on the grits and wet work
depending on suggestions. 

 

In the old days I used to use abrasive powders such as pumice followed by
rottenstone. Are these now out of vogue? 

 

Now, it looks pretty darn good as a sort of satin-sheeny thing, but what
else do some of you suggest? The final appearance I am looking for is
somewhat glossier than it is now, but not necessarily high sheen. What about
paste polishing in the final step? Use of electric polishers? Etc.

 

Thanks!

 

Nick Gravagne, RPT

Piano Technicians Guild

Member Society Manufacturing Engineers

Voice Mail 928-476-4143

 

 

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