[pianotech] permanent marker

[Encore Pianos]

For those interested in the pumice, here is a source:
http://www.woodshopproducts.com/SearchResults.asp?Search=Pumice

Mohawk makes it, so it is likely available from many sources.

I've been dry abrading my early coats of lacquer too, but somewhat
differently.  I use the 3M Scotch Brite abrasive pads for many purposes, one
of which is to level soundboard lacquer after spraying on finish.  I start
with the coarsest pad, the Maroon.  You can attach it to a pad sander just
as you would paper and use it that way.  I also staple it to a block of wood
that I have flattened and level finish that way.  I get into corners and
tight spots freehand with smaller pieces.  I knock off excessive powder with
a dust brush occasionally.  What I like about it is that it doesn't clog and
conforms to surfaces more readily than sandpaper.   I haven't tried it with
pumice, but I see no reason why they wouldn't work together well.  

What I do after my final coat of finish is to use a material called Wool
Lube, also a Mohawk product.  Here is the product description, and that is
pretty much how I use it.  

"Wool-Lube is a multi-purpose, water reducible, non-abrasive rubbing and
sanding lubricant. Wool-Lube is non-toxic and contains no silicones. Used
full strength or slightly reduced with water as a lubricant with steel wool
or abrasive pads for smoothing, removing packing marks and scratches from
finished surfaces. When reduced with water, Wool-Lube is an excellent
sanding lubricant for use with wet  dry sandpapers. Does not interfere with
the adhesion or drying of lacquer. Finishes rubbed with Wool-Lube and an
abrasive can be recoated immediately after being wiped dry. Can be used with
dry abrasive powders such as Pumice, Rottenstone, and Tripoli. Use of a
sanding lubricant greatly extends the life of waterproof sandpapers."

As it says, it does not contaminate the finish, so if you sand through, not
a problem.  I use a spray bottle to spritzer water onto the pad, but not
much.  I will refresh it while on the board if things start drying a tad too
much.  You can wipe it off with rags, which you can rinse out, wash, and use
again.  The finish comes out a nice, even satin glow, which is nicer looking
the duller dry look.  I use the grey pads (roughly equivalent to 0000 steel
wool) with the Wool -Lube. It is available from the same supplier as above,
and as a liquid or paste.  I prefer the liquid myself.  Wool lube can be
used with pumice or rottenstone.  

I have done it this way for many years, with no problems.  Recommended.  You
might find it a useful adjunct to your process, Ron. 

Will 
-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Saturday, August 25, 2012 11:00 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] permanent marker

On 8/25/2012 8:57 AM, Ron Nossaman wrote:
> It's probably much more efficient in
> time and money wasted to just Google some up and UPS it to your front 
> porch.

Hey, I forgot the most important use I have for pumice. with the key top
thing being a distant second.

To whom it may concern.

I finish soundboards with pre-cat nitrocellulose lacquer. I don't use a
filler, and I don't use sanding sealer or varnish because I don't want a
soft heavy finish on my boards. So after spraying the first coat of lacquer
on the bare spruce, I'm looking at sanding lacquer prior to applying
subsequent coats. Dry sanding lacquer, as anyone who has tried it
(especially with fresh lacquer) will tell you, doesn't work. The sandpaper
clogs up immediately. Since I have no desire or intention of flooding my
board with a liquid lubricant, I needed an abrasive that doesn't clog up. I
found that 150 grit paper on my pad sander, with the soundboard surface
sprinkled with that FFF pumice, worked wonderfully. 
The grit of the paper both does some of the cutting, acts as a matrix to
hold the pumice as it scrubs the lacquer, and the pumice keeps the paper
from goobering into uselessness. I can watch the light reflection off the
surface with each sweep as the high spots, dust, and spruce surface fur lose
their gloss and merge into a satin sheen that is an ideal surface for the
next coat of lacquer. I typically sand two coats, and topcoat a third,
leaving a finish that isn't mirror flat and raccoon shiny, but is light,
tough, and adequately sealed by my criteria. 
Exactly what I want, and used 1/4 sheet of sandpaper and a couple of
tablespoons of pumice for the entire job.

There's no reason I'm aware of that this wouldn't work in any instance, like
case touch up, where a finish or patch needs to be leveled, and the
likelihood of breakthrough and contaminating the underlying wood with your
lubricant is high (as it is with the soundboard on the first coat). 
Breaking through with pumice leaves no contamination.

Try it. You might find it useful for things I haven't thought of, which you
can then tell the rest of us about.

Ron N