Perhaps there is an Orchidian with an optical pyrometer who could
perform a test of a sharpie mark and inform us at which temperature
it disappears.
Mike DeBurgh, GJG
Alliance, OH
Perhaps there is an Orchidian with an optical pyrometer who could perform a test of a sharpie mark and inform us at which temperature it disappears.
But the question then becomes to list a few variables
Permanent or removable
What width
Which flux / firecoat
Perhaps there is an Orchidian with an optical pyrometer who could perform a test of a sharpie mark and inform us at which temperature it disappears.
A Sharpie mark is basically carbon so the amount of oxygen present
will alter how long is stays visible. Flux and torch flame type will
effect this. So you need to control for torch flame composition as
well as temperature to run your experiment. This is why there are
differing āopinionsā on whether this is a good tool for determining
annealing temperature.
If you really want to know the temperature get a set of temperature
indicating crayons. They melt at very specific temperatures and are
used by welders and others who need a quick easy field test for
temperature. They are available in a huge number of temperatures.
http://tempil.com/thumbnail.asp?cid=22
Also anything short of a two color optical pyrometer (very
expensive) will be useless for silver because of its low emissivity.
James Binnion
James Binnion Metal Arts
Perhaps there is an Orchidian with an optical pyrometer who could perform a test of a sharpie mark and inform us at which temperature it disappears.
Rather than fooling around with sharpies, I prefer the trick Charles
Lewton-Brain advised for annealing copper in one of his fold forming
workshops. The same procedure works just as well with sterling silver
and yellow golds. Using normal annealing methods, one will notice
that when the metal is cold, the flame brushes off and over it
without color change. As it gets hotter, a point is reached where the
flame, after the point it hits the metal, develops a yellow color.
This is sodium flare, and sodium is part of almost anything one might
use as a fire coat, or fingerprint oils, or whatever else. At the
point the yellow flame color becomes visible, the copper, silver, or
yellow golds will have reached annealing temp. Cool till it no longer
glows. t will only really glow in very reduced light or if your flame
lingers on the metal longer than needed, but still, to avoid cracking
the metal, be sure itās below that point, which means below about 900
degrees F.
The method is easy, doesnāt require a marker or indicator, and is
quicker to do and learn than itās taken me to type this.
(Thanks Charles for that tip.)
Peter Rowe
1 Like
Thanks James. This is one of the things I like about Orchid, I not
only learn how to do things, but also how not and why not. I find I
often need to talk over ideas so I can clarify my thoughts and find
my way to a solution. Sometimes my initial thoughts seem somewhat
vague/incomplete, but through discussion Iām able to refine them.
Thank you all for providing an avenue for this.
Iād forgotten about the temp crayons.
A question. Handy flux melts and becomes clear at approx 1100 F,
correct? Once it become clear how long should the sterling be held
at that heat for proper annealing?
Mike DeBurgh, GJG
Alliance, OH