Have you ever made niello? We're talking vast quantities of
flaming sulphur, and then stirring the burning sulphur into the mix
with a (long) rod. No way to float charcoal on it.
There is a mid-size town in Russia, called Tula. Historically it is
the center of production of edged weapons and firearms, similar to
Toledo in Spain. A lot of work done in niello there. I have spent
whole summer in Tula, between my second and third year. Learned a few
thing too.
To your question, - what makes you think that you have to stir all
the time? What makes you think that you have to stir at all? What
makes you think that if cover is used for crucible, it is impossible
to lift the cover, stir, and replace the cover?
It almost makes me to ask a question " have you ever made niello"?
But I am not going to do it.
But I am going to ask one more question:
Why do you think that one has to use sulphur at all?
In California, yes, such pieces are specifically illegal, and
there may be other states that are moving that way. Federally, the
regulations apply to childrens' products.
Not just California and skin contact has nothing to do with it.
Basically any consumer product that contains lead is in the process
of being legislated out of existence. Current federal requirements
are that products not specifically aimed at children that contain
lead in excess of the guidelines (300 ppm I think) must have a
warning label attached. The CSPC has advised all manufacturers to
phase out lead in all consumer products.
Hmmm, hadn't thought of substituting tin for the lead. I think I
will have to try a small batch to see how it works.
The thing about niello is that there are thousands of way to make
it, and everybody who is specializing in it, has this own recipe.
Niello is about combining silver and sulphur, which is difficult to
do because of vast difference in melting points. In lab environment
it is done in quartz, vacuum sealed ampule. But this approach is not
suitable for a shop. So there are two ways to go about it. One way is
to reduce the temperature of alloy, before introducing sulphur, and
another is to use sulphur which already has been bound to a metal.
Covellite is alloy of copper and sulphur, at least in pure state.
Smelting it with silver should give lead free niello, but with higher
melting point. Adding tin will lower melting point of the alloy. The
problem in using copper minerals is that without a lab it is
difficult to know what do you actually have. But once success is
attained and source does not change, the things will go smoothly. If
you really feel adventurous, consider pyrite, which is alloy of iron
and sulphur. There is no law, which says that iron cannot be used in
niello, and it’s presence will give bluish tint. Of course, higher
melting point is overcome with addition of low melting metals.
No discussion of niello is complete without mentioning Bismuth,
which is a very good replacement for lead. Mineral Bismuthinite is an
alloy of Bismuth and sulphur. It’s use gives another option of
introduction of sulphur in niello. In conclusion, there are many way
to skin a proverbial cat, and even more ways to make niello.
No worries. Mostly what I knew is that it stung like a bastard
getting it in my eyes. I ran the chemistry (roughly) in my head, and
said to myself “sulfuric”.
The next words I said were “Where the H*ll is my full-face
respirator??” That’s about as much thought as I gave it, beyond an
ongoing resolution never to do it in open air, or without a
full-face respirator again.
As far as your buddy in the shipyard goes, yeah, that doesn’t
surprise me. Lead paint was based on flake white, which is a lead
chromate. Metallic lead doesn’t metabolize all that well, but lead
chromate (and lead oxides) do metabolize very well indeed. Once
it’s been taken up by the body, it does all sorts of nastiness to the
nervous system (This came from a conversation with my doctor, after
I’d ground the “bondo” off an old screwpress I’d picked up. Turned
out to have been powdered metallic lead bound in linseed oil. They
ran my lead levels after that, and they weren’t particularly
elevated. Full on lead metal really doesn’t metabolize all that
easily.)
Shipyards also used a lot of red lead, which is lead tetroxide. It’s
particularly soluble in stomach acid, so again, very easily
metabolized.
To your question, - what makes you think that you have to stir all
the time? What makes you think that you have to stir at all? What
makes you think that if cover is used for crucible, it is
impossible to lift the cover, stir, and replace the cover?
Stirring? Got that from Phil Fike, the guy who taught me how to make
it. Given the way he made, and I make it, a crucible cover would get
in the way. So, no it would be physically impossible to have a cover
there in the first place, nevermind lifting it.
It almost makes me to ask a question " have you ever made niello"?
But I am not going to do it.
Plenty. Done workshops on it even.
But I am going to ask one more question:
Why do you think that one has to use sulphur at all?
You mean besides your next post where you talk about niello being an
alloy of silver and sulphur?
In the niello course I developed for the Bezalel Academy of Art and
Design in Israel back in the early 80’s, students learned thirteen
different techniques for making and applying niello. Not only the
techniques are different, but different formulas have VERY different
working properties! (I have collected over forty niello formulas
from sources spanning a period of 2000 years.) The Pliny formulas
(1st c. AD), by the way, have no lead… My students were required
to make up seven different specified niello formulas and run
experiments to test the differences. Some are sticky and need to be
spread while hot (Theophilus, Cellini) which is great for spherical
objects (like goblets), while others liquefy quickly and flow rapidly
(Persian and 16th c. Russian) which is good for engravings. This was
a semester course which gave the students an excellent starting point
from which to explore the potential of this unusual material which
has many, many variations…
I found niello very quick and easy to make, so I’m not sure why
others found it so messy. Maybe it was because I developed a
synthesis technique based on many sources [including Theophilus
(1140), Cellini (1658), Wilson (1902), Spon (1909), Maryon (1912),
Moss (1953), Fike (1958), Hollingshead (1963), Untracht (1968),
Untracht (1982), Edwards (1977), Evans (1983)]. A major part of the
course was not only to study all the different ways that niello had
been made throughout the centuries, but also to try to understand
what caused what. We used my synthesized technique in class, but the
students were expected to try to improve on it given the chemistry,
etc. they learned while studying the different techniques. The
resulting niello samples and exercises were fascinating…
Please note that I have always made my niello in PROPER FUME
CUPBOARDS! This may well have added to the apparent ease of the
preparation…
Janet in Jerusalem
P.S. No other material has the beautiful sheen of niello…:-)…
I want to thank Leonid for his excellent addition to the thread on
making niello. I haven’t tried his suggestion of rolling out the
copper to a thin sheet, glazing it with flux, and melting the silver
first. Sound like it would work. Also, I have always wondered if the
lead was necessary and also if tin could be substituted for the lead
to lower the melting temperature. I’ll have to try that. Thank you
again, Leonid.
Stirring? Got that from Phil Fike, the guy who taught me how to
make it. Given the way he made, and I make it, a crucible cover
would get in the way. So, no it would be physically impossible to
have a cover there in the first place, nevermind lifting it.
Let’s take simple formula,- copper, silver, lead, sulphur. The smart
strategy would be to alloy copper and silver, then lead and sulphur,
and then 2 alloys together. Let’s talk about alloying lead and
sulphur. Melt lead, allow it to set and upturn crucible to get cake
out. Place powdered sulphur on the bottom, put cake of lead on top,
cover up with charcoal and melt. Shake crucible from time to time.
No need to remove the lid. It may require little stirring at the end,
or may not. In any even, it is less messy with much better fumes
control.
Let's take simple formula,- copper, silver, lead, sulphur. The
smart strategy would be to alloy copper and silver, then lead and
sulphur, and then 2 alloys together. Let's talk about alloying lead
and sulphur. Melt lead, allow it to set and upturn crucible to get
cake out. Place powdered sulphur on the bottom, put cake of lead on
top, cover up with charcoal and melt. Shake crucible from time to
time. No need to remove the lid. It may require little stirring at
the end, or may not. In any even, it is less messy with much better
fumes control.
The problem with this approach is that lead does not alloy with
sulfur; it reacts with it to form a compound, lead sulfide, chemical
formula PbS. You can only get as much sulfur to combine with the lead
as will make PbS molecules, the excess will burn off or remain in the
crucible as solid sulfur.
If you drop a lump of PbS into molten silver will the sulfur break
from the lead to make silver sulfide, Ag2S? And if the PbS does break
up that will leave behind pure lead.
No, you need to alloy the metals first and then add a surfeit of
sulfur to ensure that there is enough to go around.
I’m drawn to Cellini’s method of using a narrow mouthed clay vessel
which you can stop up once you’ve added the sulfur. This has the
advantage of keeping the sulfur fumes in and excess oxygen out. I
don’t know if such high-heat flasks are available these days. You’d
need a good supply, as the flask had to be broken to get the niello
out.
Regarding tin as a substitute for lead in the recipe, our chums at
Wikipedia tell us that tin sulfide, SnS, is a brown solid. So that
would change the color of the niello from black to brownish-black.
How brown would depend on the proportion of tin in the mix. This
slightly warmer color niello could be very attractive. Might look
really nice on gold.
The problem with this approach is that lead does not alloy with
sulfur; it reacts with it to form a compound, lead sulfide,
chemical formula PbS
First observe that all recipes for niello given in parts, (volumes),
and that is very important to keep it in mind. Let’s compute mole of
PbS. Atomic weight of lead is 207 and sulphur is 32.
Mole of lead sulfide is 239 grams. It means that 207 grams of lead
will completely react with 32 grams of sulphur, creating 239 grams of
lead sulfide.
Lead density is 11 and sulphur is 2. 207 grams of lead is
approximately 2 cubic centimeter, and 32 grams of sulphur is 16 cubic
centimeters. So 2 parts of lead will completely react with 16 parts
of sulphur. To simplify, the ratio is 1 to 8. For niello preparation,
most ratios are 1 to 1, so we have a huge safety margin, and your
concern is not justified.
No mercury involved in Niello, niether Phillips method, nor other
traditional or ancient ones I'm aware of...
Heraclius’ niello recipes included mercury (“quicksilver”).
Regarding lead-free niello:
Relatively pure copper sulfide or silver sulfide niello must be
applied by grinding up the material, packing it into the area to be
decorated, followed by repeated gentle heating and burnishing to fix
it into place. Both sulfides are malleable at room temperature, and
much more so when heated, but both decompose in air before melting,
and thus they cannot be fused into place. On the other hand,
silver-copper-lead niello is readily fusible, and thus may be
applied like enamel.
niello is a process that originated in India perhaps 5000 years ago
since examples have been found in ancient sites that pre-date nilotic
egyptian culture and pyramids - it is not modern at all!
It is fairly straightforward and requires excellent ventilation if
you are even toying with making the stuff indoors- which I
wholeheartedly DO NOT RECOMMEND, in fact I recommend doing it out of
doors, only packing the stuff into your design indoors with gloves
on ( nalgene or neoprene over latex gloves at that ). Once the
chemicals and metals are assembled have two dedicated crucibles
available for the process (one for copper and the other for lead
mixtures) you won’t be able to use them for any other material/alloy
or purpose- in fact you can use fused clay cuppols instead of
crucibles ( like assayists crucibles- about 12 bucks per dozen and a
half in a box holding about a max. of 2 oz. 's each. )- or make
disposable eqipment for the process out of thick sided greenware and
raku it if you want to do it quickly and can’t wait for ordering
crucibles, or have another reason to get on with it. as greenware/
clay that is fully fired will initially not absorb or stick to
elements of the admixture ).
once rady to proceed - that is,after reading any articles and books
on the process ( oppi untracht has a fairly complete explaination in
"… techniques for metalsmiths", and I believe Tim McCreight’s
classic “Complete Metalsmith” also gives a condensed instruction set
too) - write a task list and follow it. prepare to do the entire
operation in a day as opposed to beginning it later in your day and
having to close, deal with customers or have other interruptions or
quitting time approaching wiht the process left in limbo till next
day - it will fail if you are in certain phases of the process… It
won’t stick to some metals- platinum for instance, high copper alloys
for another, fine silver, karated golds, and phosphor bronzes are
suitable - i’m not sure about titanium or niobium … the contrast of
the stuff makes great visual effects but not textures…so keep that
in mind when creating your design or experimenting with inlay
options… if you just wantthe contrast of black on x metal though
there are many excessively easier and safer process and materials you
can use to both colour and 'pack in" or fill excised areas with… Not
that i am against niello use- just that given that you are in essence
getting metal to absorb, or become “saturated” with sulfur- any of
the alternatives are pretty attractive! Equally, I think, if you’re
interested you should by all means, explore the technique and the
making of the stuff… in india for instance some jewelers
/metalsmiths spend their entire carreers becoming niello
artists/masters… also niello isn’t something that you can keep on
hand and use occassionaly- once made use all you can and perhaps
contain the leftover ( which in the designing you can plan NOT to
have leftovers at all in estimating the weight you want to result
after the process) for remelting sometime in the future… ) due to
getting it to a workable consistency/state during processing…once
its brittle it has to be remelted ( which means melting and adding
yet more sulfur!)…
So I would plan for a day to do the work, and allow for some
mistakes initially until you get the feel for when it is right, then
have your workpiece already prepped and ready to accept the material.
Working with it warm ( if you use it in the “mass” state as opposed
to making a “stick” or rod of it is easier than letting it completely
cool- if you can work fast enough to fill a design. Otherwise,
perhaps “drawing it down to a wire or shaped wire ( rectangle, crazy
8 /double peaks, etc. ) using a B&S screw guage - instead of your
best sapphire lined drawplate - ad frequently lubing it with beeswax
or a mixture of carnauba and beeswax as it requires lubrication to
draw at all as it tends towards breakage, or brittleness if poured
into a shaped “wire”. - is an option if you need it in a consistent
"feed” that you simply line up with the incised area and pack in…
I’m not sure if any of this will be helpful but that’s all I can
think of since apparently you have a recipe…if you have any specific
questions feel since apparently you have a recipe…if you have any
specific questions feel free to contact me off list but expect a
delay of at least 24 hours for a reply… rer.
