To Quench or not to Quench?

What is the bottom line as far as quenching in pickle?
In school (way back when) it was grilled into my head "Never-Ever-Ever
quench anything in the pickle" though many people do...
I was never clear as to why one should or should not.
Possibly a safety issue (splash in eye) or for technical reasons.=20
Some people seemed to think the metal would clean up better or faster
by quenching, while I've also heard that it makes firescale worse???
Is there a carved in stone rule? Or does everyone do it their own way?
Any info would be helpful.
Thanks!

"Jenny" wrote in message
...

Is there a carved in stone rule?

Don't quench when your project is hot, let the hot acid/pickle
(sulphuric) do the work while the jewellery that you want to put in
it, is cool to the touch.

-SP-

-SP- wrote:
=20
"Jenny" wrote in message
...
=20
Is there a carved in stone rule?
=20
Don't quench when your project is hot, let the hot acid/pickle
(sulphuric) do the work while the jewellery that you want to put in
it, is cool to the touch.

Why?


--=20


If you try to 'reply' to me without fixing the dot, your reply=20
will go into a 'special' mailbox reserved for spam. See below.


--
Carl West http://carl.west.home.comcast.net

change the 'DOT' to '.' to email me

If I had six hours to chop down a tree,=20
I'd spend the first four sharpening the axe.
- Abraham Lincoln

On Sat, 17 Jan 2004 21:43:30 -0800, in rec.crafts.jewelry Carl West
wrote:

Don't quench when your project is hot, let the hot acid/pickle
(sulphuric) do the work while the jewellery that you want to put in
it, is cool to the touch.

Why?

Safety. Quenching hot metal in either water or pickle causes too things.=
One
is the splash and splatter, sometimes, of larger droplets of liquid. If =
water,
ti's harmelss. If acid, even the dry acid compounds like sodium =
bisulphate
pickles (Sparex, etc), it will eat holes in your clothes, and since it's =
often
hat to begin with, can scald you. Even if you don't mind a few holes in=
your
T-shirt, I guarantee you would not like the feel of such splashes in your=
eyes.
Why take the chance. Also, when hot metal hits the pickle, especially =
when it's
hot pickle, some much tinier droplets, a mist, mixed with steam, is sent=
up.
though this isn't a large amount, it's not healthy to breath.

Just quench in water first. Then put the now cooler metal in the pickle.=
It
need not be cold, just below the boiling point of water, so it doesn't =
splash,
or cause that steam/mist combination. Pickling is still almost as fast =
this
way.

Another aspect of this is tha simply quenching in water doesn't =
automatically
remove all fluxes. In some cases, you can chill a piece quick enough =
that you
can then place additioanl pieces together and solder again without =
needing
additional fire coat or flux. Not always, of course, and experience will=
teach
you when you can do this. But it can be a time saver. Those laboriously
spraying prips flux on their silver, in particular, are an instance where=
this
can save time. Once the piece has gone in the pickle, the flux is gone.

In both my home shop and the one at work, using just a water container at=
the
bench allows the pickle pot to be some distance away from where one =
actually
sits and works the most. Again, this is better for the lungs, as well as
avoiding some problems with rusting of tools that are too close to a =
pickle
pots's fumes.

cheers

Peter

"Carl West" wrote in message
...
-SP- wrote:

"Jenny" wrote in message
...

Is there a carved in stone rule?

Don't quench when your project is hot, let the hot acid/pickle
(sulphuric) do the work while the jewellery that you want to put in
it, is cool to the touch.

Why?

Because it will 'freeze' the crystalline structure of gold and
silver (not sure about platinum), at the moment of insertion and will
form cracks, or the surface can end up looking like 'orange peel', or
both. I said "cool to the touch", but warm is also ok, not hot.

-SP-


Carl West http://carl.west.home.comcast.net

On Sun, 18 Jan 2004 10:30:58 -0800, in rec.crafts.jewelry "-SP-" =

wrote:

Why?

Because it will 'freeze' the crystalline structure of gold and
silver (not sure about platinum), at the moment of insertion and will
form cracks, or the surface can end up looking like 'orange peel', or
both. I said "cool to the touch", but warm is also ok, not hot.

Well, maybe, sorta, but not really, Carl. It depends on how hot. Most =
folks
quenching their work after soldering do it once the work has dropped =
below about
900 - 1000 degrees F., by which time the metal will no longer be glowing.=
At
these temps, it's safe, for the metal at least, to quench most of the =
jewelry
alloys. and in fact, in working with many of them, quenching at about =
this
point can result in substantially softer and more workable metal, since =
it
doesn't allow the metal to age harden. Some white golds, and especially =
some
rose golds, can become significantly harder if allowed to just air cool, =
and
with a few, such as an 18K rose gold made with just gold and copper, can =
become
so hard as to be brittle, if air cooled. Problems people have with =
brittle
rose golds cracking and breaking on them generally result from not =
quenching,
rather than quenching. You generally WANT the metal to keep the more
randomized structure it has while hot. However, your statement is true =
if
we're talking about quenching from significantly higher temperatures. =
Many of
the gold alloys, as well as sterling silver, don't have much tensile =
strength,
when very hot, so if you quench it from, say, red hot, the stresses set =
up by
shrinkage of cooling metal can cause cracking. When I was in graduate =
school,
I explored this a bit, since by quenching sterling silver forms from a =
higher
temperature like that would shatter it, with cracks and shapes I could =
never
have gotton by normal intentional means, an effect I used in a number of =
peices
where I wanted those cracks and fissures. But I also went through a lot =
of
silver to get the pieces I wanted...

As to the issues of "orange peel" surfaces, this is indeed heat realated,=
but
has little to do with quenching. When the metals are heated hot enough, =
the
crystals in their structure start to combine and grow larger. This grain=
growth
is generally something you don't want (with one exception I'll get to), =
since
larger grain structure means weaker metal. And if the grain size gets =
large
enough, then the weaker boundaries between the grains will indeed give =
rise to
an orange peel effect when the metal is polished, and especially, if it's=
bent
or formed after that annealing. But usually, the temps needed to cause =
this to
a damaging degree are higher than usually used in soldering or annealing.
Quenching the metal once it's cool enough to do without cracking it, =
stops the
grain growth, rather than promoting it. Mostly this is important with =
platinum,
which CAN be quenched from virtually the point it's fully solidified, and
quenching your platinum work will help keep grain growth to a minimum. =20

The exceptions to wanting to prevent orange peel refer to intetionally =
age
hardening the metal, especially sterling silver. You'll get the highest =
degree
of hardening if you first anneal the silver to a rather higher temp than =
normal,
which is indeed high enough to promote grain growth, and quench it from =
as high
a temp as is safe. This ensures that the copper content of the metal is
uniformly still in solid solution in the silver crystals. If allowed to =
slowly
cool, the silver's structure changes to two different compositions of =
crystal,
one a solid solution of silver with about 28 percent copper, if I recall,=
ei
the eutectic composition, and the other, almost pure silver. Age =
hardening of
the silver is most effective if you've locked the composition of the =
crystals by
quenching to the high temperature uniform structure, since then the =
subsequent
prolonged low temperature heat treatment gives the most complete and =
uniform
precipitation hardening of the silver, which is caused when that copper =
comes
back out of solid solution, forming new crystals at the silver grain
boundaries. The process is a bit more complex metalurgically in the gold
alloys, but amounts to the same thing in practice.

the bottom line, quenching from too hot, as in still glowing, can crack =
and
damage gold and silver alloys (platinum doesn't mind), but other than =
that, is
often a good thing, especially if you wish the metal to remain as soft =
and
workable as possible. (It's just the opposite of steels, which need to =
slow
cool to be soft) Some white golds can be particular as to just how and =
when
they are quenched, and you need to work out a particular method for each=
white
gold alloy. With some of them, problems with cracking during quenching =
can be
avoided by quenching in alcohol, rather than in water. it's a slightly =
slower
cooling for the metal, but still fast enough to lock in, sufficiently, =
the
higher temperature structures and avoid age hardening. Rose golds in
particular, respond well to this. Obviously, this must be done with a =
bit of
care, since alcohol is flammable. You quickly immerse the hot metal in =
the
alcohol, so then there is no oxygen where the alcohol is being vaporized =
at the
surface, and nothing catches fire. But occasionally, if one isn't paying
attention, one's torch flame might be close enough through all this to =
set the
alcohol on fire. the main thing is that the alcohol should be in a =
decent glass
or metal container with a lid. Unlike some more volatile solvents, the =
alcohol
just ctaches fire. it doesn't get dramatic or explosive or anything. =
You need
to be prepared to just put the lid on the jar to put out the flame. =
Simple
enough. The danger isn't the fire itself, it's that if you get startled =
by the
alcohol catching fire, you might drop or tip the jar. A little flame =
coming
from the top of a small jar of alcohol, on which you can put a lid, is =
not a
dangerous thing. But dropping the jar and having your whole bench pan
suddenly aflame from the spilled burning alcohol, can get very exciting =
very
quickly. So be careful.

In general, reasons not to quench would be if there are elements in the =
work
which cannot take the thermal shock of quenching (virtually any stones, =
for
example, as well as some fragile soldered constructions, which might warp=
if
quenched. And often, it just doesn't matter to the work if it's quenched=
or
not, so then why bother. But to get back to the original question of =
quenching
in pickle, there are good reasons to not do that. Mostly related to the =
safety
of the jeweler, not the metal. Splashing hot acid around the shop is =
generally
just not a good idea.

cheers

Peter Rowe

"Peter W. Rowe" pwrowe@ixDOTnetcomDOTcom wrote in message
...
On Sun, 18 Jan 2004 10:30:58 -0800, in rec.crafts.jewelry "-SP-"

wrote:

Why?

Because it will 'freeze' the crystalline structure of gold and
silver (not sure about platinum), at the moment of insertion and will
form cracks, or the surface can end up looking like 'orange peel', or
both. I said "cool to the touch", but warm is also ok, not hot.

Well, maybe, sorta, but not really, Carl. It depends on how hot.
most folks quenching their work after soldering do it once the work has =
dropped
below about 900 - 1000 degrees F.

Yes, and the people that don't do it, and quench when hot - you and
I get to repair their 'craftsmanship'. I see it all too often - you
know when a ring with a broken shank has been in the pickle too hot
because when you look at the surfaces of the break, they are clean,
bright, and with a big crystalline structure.

As for the rest of your advise Peter, that's sort of what I meant to
say, but you have an exceptional way of explaining things - much
better than me.

-SP-

On Sun, 18 Jan 2004 11:41:44 -0800, in rec.crafts.jewelry "-SP-" =

wrote:

Yes, and the people that don't do it, and quench when hot - you and
I get to repair their 'craftsmanship'. I see it all too often - you
know when a ring with a broken shank has been in the pickle too hot
because when you look at the surfaces of the break, they are clean,
bright, and with a big crystalline structure.


We certainly do now and then get to work more, on the poor craftsmanship =
of
those who don't know what they're doing. But as I said, quenching from =
too
hot, while it might crack the gold, is not the cause of that coarse =
crystal
structure. It would be heating it too hot, that does that, or most =
commonly, it
would originate from the original casting process, with the mold =
temperature too
hot, or the alloy choice incorrect for casting. The latter, improper =
casting
technique, is the major cause of really coarse crystal structures and =
cracky
metal. Often, shanks that crack do so also due to a lot of casting =
porosity
weakening the metal. Quenching wrong might expose the existing faulty =
metal,
but it's not the cause. Those really dramatic examples, where the =
breaks are
large bright crystals, are perhaps better off breaking in the shop, =
either from
quenching, or from some other cause. They'll not hold up well in a =
customers
hands either, so perhaps it's best we find out about it and can fix it =
before
they get it. I've seen some such castings, fresh from the manufacturer =
and
never worked on by any bench person, literally shatter when just dropped =
on the
floor. Rare, but i've seen it happen. Nevertheless, as you say, =
knowing which
metals can be quenched safely, is part of proper carftsmanship. And as I
pointed out, sometimes that also means knowing that you have to quench =
certain
metals, to avoid the problems. =20

As for the rest of your advise Peter, that's sort of what I meant to
say, but you have an exceptional way of explaining things - much
better than me.

Gosh. Thanks. And it helps that I type fast too... (grin)

cheers

Peter

"Peter W. Rowe" pwrowe@ixDOTnetcomDOTcom wrote in message
...
On Sun, 18 Jan 2004 11:41:44 -0800, in rec.crafts.jewelry "-SP-"

wrote:

Yes, and the people that don't do it, and quench when hot - you
and
I get to repair their 'craftsmanship'. I see it all too often - you
know when a ring with a broken shank has been in the pickle too hot
because when you look at the surfaces of the break, they are clean,
bright, and with a big crystalline structure.


We certainly do now and then get to work more, on the poor
craftsmanship of those who don't know what they're doing. But as I =
said, quenching
from too hot, while it might crack the gold, is not the cause of that =
coarse
crystal structure.

Ok.

It would be heating it too hot, that does that, or most commonly, it
would originate from the original casting process, with the mold
temperature too hot, or the alloy choice incorrect for casting. The =
latter, improper
casting technique, is the major cause of really coarse crystal =
structures and
cracky metal.

Those are fair points, and I can see this, but in my experience, I
haven't come across any casters (yet) that produces anything other
than a few pits in rose gold. I've seen bad mould alignment, bad
flash, but not bad castings as in heat related problems, (apart from
the pitting of course...)


As for the rest of your advise Peter, that's sort of what I meant to
say, but you have an exceptional way of explaining things - much
better than me.

Gosh. Thanks.

My pleasure, sincerely.

And it helps that I type fast too... (grin)

And that, you do.

-SP-

On Sun, 18 Jan 2004 14:49:42 -0800, in rec.crafts.jewelry "-SP-" =

wrote:


Those are fair points, and I can see this, but in my experience, I
haven't come across any casters (yet) that produces anything other
than a few pits in rose gold. I've seen bad mould alignment, bad
flash, but not bad castings as in heat related problems, (apart from
the pitting of course...)


It doesn't seem common. At least not as common as it was, say, 20 years =
ago.
And even then, it never was common. But over theyears, it seems that =
most of
the cases I've seen of those really bright crystaline breaks you refer =
to,
tended to occur in new castings. The problems with older jewelry, or =
repairs,
tended to be cracky crumbley metal more related to porosity, or to the =
age
hardening and cracking problems that white golds and rose golds can =
experience
with improper working (which is what you've been pointing out). =20

With regard to the new castings, I'm not sure, but suspect that many =
times it
was due to improper use of added deoxidizers and grain refiners, as much =
as to
overly high casting temperatures.. When silicon deoxidized alloys first =
became
available, some folks added too much, which can cause cracky metal and =
other odd
effects. People have gotten more used to these alloys now, and =
especially, the
refiners have kind or learned to determine what technology a jeweler or
manufacturer is using, and matching the alloys suggested/sold to those =
means.
=46olks using induction melt machines that melt under an inert =
atmosphere, for
example, can use different alloys than those who are torch melting the =
metal.
Just yesterday, in the mail, I got the new Rio Grande tools catalog, and =
one new
section is master alloys for alloying your own gold. For each =
color/karat type
of alloy, they have several types, depending on whether it will be used =
for
fabrication, or for casting, and within the casting alloys, they have two=
types
as well, for each, matched to the traditional torch melt method, or to =
more
modern methods using better protection of the metal. The descriptions in=
the
catalog of just which alloy is best for a given method is still rather =
vague,
but this is still a far cry better than what we used to see, alloys =
catagorized
for just karat and color, or with no mention of which might be better for=
which
uses.=20


And even the fuel gas used in torch melting makes a big difference. =
When, where
I work, they finally switched from hydrogen/oxygen to propane/oxygen, =
many of
the porosity and brittleness problems we'd had with white gold went away.=
I'd
been telling them that for years, but I guess they didn't believe me =
till the
metalurgists at a new metals supplier they tried told them that too... =
(sigh)

Peter