On 2012-11-27, Ike Milligan <
accord...@mindspring.com> wrote:
[ ... ]
> The idea of using transmission fluid is intereting instead of 3-in1 oil as I
> suggested. I have used liquid WD-40 and it is veryh good at loosening rust.
> I am told in a post in this group that it is bad for reeds, probably because
> it is acid. Wood alcohol and ammonia with some tranny fluid (not the
> cross-dressing kind -- I know some of you would try to make poor jokes)
> would be interesting. I would not have the time to be soaking reeds for
> months. Another interesting idea would be boiling in olive oil, if thatwill
> not de-temper the steel.
You mean "anneal", I presume (render softer). Tempering follows
heating to a critical point (when it is no longer attracted to a magnet,
a red glow), and quenching, which makes the steel *very* hard and
brittle. Tempering is then the process of heating it to a certain
temperature for a time proportional to the thickness (IIRC, about 1 hour
per inch of thickness, to allow the heat to soak to the middle). Select
the temperature (to match the steel alloy) and hold it at that
temperature to get a specific reduced hardness better for the
application.
Above a certain temperature, the steel is fully annealed (made
as soft as it gets), and to get harder you have to heat, quench, and
temper again.
Looking up the boiling point (and understanding that it varies
with the actual composition of the oil batch in question, so measure
your batch) I see 300 degrees C (572 degrees F), which is up into the
range for tempering hardened spring steel.
From the Wikipedia entry on tempering, I find the following
colors vs tempering temperature.:
======================================================================
Purple ? 282C (540F) ? surgical tools, punches, stone carving tools
Dark blue ? 310C (590F) ? screwdrivers, wrenches
Light blue ? 337C (639F) ? springs, wood-cutting saws
======================================================================
So -- it is up to you to determine the color of the steel
(underside, of course) and decide whether extra time at that temperature
would change it. I would expect "springs", which would probably not
change much, but if it is "Dark blue" it is likely to change somewhat,
and if it is "Purple", it certainly would change. (These colors are
what you would get by heating polished metal to that temperature in air,
so you would not see the same changes in color from boiling it in oil.
Of course, you could mix in a lighter oil to reduce the boiling
point, but this might not give the proper cleaning and de-rusting. And
the lighter oil would boil away first, slowly changing the boiling point
upwards. And really -- the de-rusting either requires mechanical
abrasion of some form, or a chemical attack which absolutely should
*not* be used with reeds riveted to *any* dissimilar metal.
> I have to use the elbow grease in the method I use
> now, which involves doing one side of a block at a time and keeping the
> reeds in a row except when I do soak them overnight, which does not remove
> th rust.
Understood. Perhaps scratch an identifier into the reed plate
in case they get mixed up somehow.