Rust On Piano Strings

Just thought I would put a couple thoughts in the mix.  I am not a
piano tech.  I just love the old players and the mechanical wonders
inside. When I look at pianos that are close to 100 years old I have
not personally seen one that does not have rusty or corroded strings.
It sounds like in the first post that they were looking to clean and
protect new strings.

Your hands do have some oils in them but what does the damage is the
sweat that contains salts.  I have worked in the metal working industry
for about forty-five years, and rust is always an issue, especially in
hot and humid climates.  If you are having the strings replaced, the
tech should be wearing the thin latex or butyl gloves to keep the salts
off the metal.

I also saw someone suggesting the use of naphtha to clean the strings.
The best thing to remove the salts is actually water and mild soap, but
I know you cannot get water inside the piano.  A good carnauba wax,
found in very good car wax, will give you a protective layer on the
steel and copper.  With no protection, any material will oxidize over
time.

I am also a hunter and go on extended trips to Africa which can give
some harsh weather, 100 degree temperature, 98% humidity, dirt, and
lots of sweat.  I have had friends tell me that their guns rust no
matter what they put on them, oil, WD-40, gun cleaner, etc.  The
problem is that the oil will not dissolve the salts from sweat; it just
seals them to the metal.  You have to remove the salts with hot soapy
water, and dry the gun, and then apply the oil.  That is what I do when
I return home.  I have no rust on my guns, and some sit in the safe for
years without being cleaned or oiled, and I do not control the humidity
either.

Metal does not know if it is in a piano, car, or gun; so keep your
hands off the unprotected metal, and if you need to clean where someone
has touched it, soap and water is the best to clean.  Then apply a
barrier to prevent the atmosphere from also causing rust and corrosion.

To satisfy your own mind you can do somewhat of an accelerated salt
spray test at home.  Take a piece of raw steel that is not coated with
zinc or aluminum.  Clean it with lacquer thinner or acetone and then
wash it with hot soapy water,  and dry it completely with towel and
hair dryer or heat gun.  Wear gloves while doing this.  Now apply some
strips of masking tape to leave some 2" wide areas exposed.  Apply
different oils, waxes, WD-40, etc. to the exposed material, just like
you would treat your piano parts.  Now mix up some table salt in hot
water.  Take a spray bottle and spray your test piece with the salt
water and place it somewhere it is humid or even outside.  Apply the
salt spray every day and note which areas resist rust the longest.
That is what you should use.  Salt spray testing is done in the
automotive world every day.  You can do this with different paints
also to see what works best for you.

David Fowler