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Fine silver cloisonne wires and cracking


#1

Hello,

I’d really need some help. When I use fine silver cloisonne wire in
my enamels, (both on very domed pieces or slightly domed pieces, and
either on fine silver bases or on copper) I get cracking against the
wires, either in little semi circles or big ones. This can happen
within a day or two, or more usually over a longer period of time. I
do counterenamel and I have no problem with my cloisonne enamels when
I use copper wire. any insight would be greatly appreciated as I am
getting really quite desperate.

many thanks, Sarah


#2

Sarah- Are you letting the silver wires touch the copper? If so they
will alloy with the copper and cause failure. Always first use a
flux layer before applying the silver wires.

Have fun and make lots of jewelry.
Jo Haemer
www.timothywgreen.com


#3

Sarah, Are you sure that you are using the right flux? If you are
using Thompson enamels, you should use 2030 on silver (if I remember
correctly). There is another flux specifically for copper. What
happens if you refire? Did you put your wire in an acid? Contact me
offline if you like.

Leach


#4

thank you both for your help.

I think the problem might be the flux, as I’m using enamels for
copper, I do put a layer of flux for silver over a silver base, then
I swap to my copper enamels. I think perhaps I need to buy some
enamels for both silver and copper.

many thanks, I no longer feel quite so desperate.

Sarah


#5

Hi Sarah,

Your problem is not the enamel. It doesn;t matter if you use flux
for silver on copper. It works beautifully. The only difference in
the flux is that flux for silver is formulated not to turn yellowish
on the silver. Been using it for years on both silver and copper.

It could be that you are mixing leaded and unleaded enamels. That
will definitely cause cracking. If you must mix them on the same
piece, ALWAYS have the unleaded on the botton only with the leaded
on the top. Even then, you could have problems. I find that it’s best
never to mix them.

Go the the website for the Enamelist Society, enamelistsociety.org
and you will be able to find out if there are any cloisonne classes
in your area.

If not, you might like to go to camp for “adults”. There are many
art schools that teach cloisonne classes. John C. Campbell in North
Carolina, Arrowmont in Nashville…go to their websites and you will
find lots of good"stuff"

Get Linda Darty’s Book, The Art of Enameling. Lots of good
There are other good books as well but many are no
longer in print.

Donna


#6

Hi Donna,

thanks for your answer. that will save me buying new enamels. I only
use unleaded enamels but I think part of the problem may be that I
am not careful enough to keep my wires completely clean, and maybe I
am also not careful enough in applying thin layers and air bubbles
are getting in and causing cracks. I’m going to have a go using all
the advice I’ve been given and hope for the best.

many thanks Sarah


#7

Cracking, especially near the wires in cloisonne is usually due to
layers of enamel expanding and contracting at different rates.
That’s why it’s important to do test firings. You just need to
change the enamels you’re using and find one that have approximately
the same rate of expansion.

Tony Konrath


#8

Hi Sarah,

In order to assess what’s wrong, I need more

What gage of fine silver is your base?

What specific enamels did you use for base-coat, counter-enamel and
your cloisonne work?

How did you prepare the enamels to be used?

Did you use any type of binder?

What type of kiln are you using to fire? At what temperature and
time?

Gwen Bernecker
http://www.twoolivesstudio.com

Enameling Classes available at:
http://www.beadandbuttonshow.com


#9

Sarah,

Air bubbles in the enamel cause pits, not cracks. Once you have your
basecoat of enamel down and then you fire in those wires, the heat
from the kiln will burn off anything that’s on those wires. So you
don;t have toworry about cleaning those wires. I have never cleaned
the wire…just use it exactely the way it comes from whoever made
it. However, there are times when I want the wire softer so it gets
cleaned when I anneal it.

You should always apply your enamel in thin coats anyway. Even many
layers of the same color will darken that color. Remember, you can
always add more or another color to make it darker but’s hard to
remove it and make it lighter once it’s all fired.

Donna


#10
Your problem is not the enamel. It doesn;t matter if you use flux
for silver on copper. It works beautifully. 

I don’t agree. If you use silver flux on a copper piece that needs a
lot of firings, the copper will bleed through the flux unless you
fire low except for the final firing (or maybe unless you use a lot
of flux, which is undesirable). So, it does matter to use the right
flux. Note that beautiful results are in the eye of the beholder.
Since Sarah’s enamels crack both on silver and on the copper, the
problem has to be the enamels. Dirty wires do not make sense and not
much of anything does either. Mixing leaded and unleaded does not
cause cracking - I do that often. To me, this problem is a mystery.

Leach


#11

Sorry, I disagree Leach. Been doing cloisonne for over 30 years and
have never had a problem with silver flux on copper. and yes…there
can be a problem mixing leaded and unleaded enamels. You have just
been lucky. Speaking to the experts at Thompson enamel, where
unleaded enamel is manufactured, they advised me not to use unleaded
on the back as counter enamel if I am going to use leaded on the
front.

Donna


#12

Donna, I did not say that mixing lead-free and lead-bearing enamels
cannot cause problems. The colours can bleed into each other or
discolour or whatever, but it does not explain any cracking after a
couple of days. As for the copper, take a sheet, divide it mentally
into two halves, sift a tin layer of silver flux on one half and an
equally thin layer of hard flux on the other half and fire it ten
times. Don’t you see a difference?

Leach


#13

Donna,

Thanks for the info about not using unleaded counter on a leaded
piece. I’ve always wondered about that. What do you use? Is there a
"general" leaded counter enamel?

vera


#14
Speaking to the experts at Thompson enamel, where unleaded enamel
is manufactured, they advised me not to use unleaded on the back as
counter enamel if I am going to use leaded on the front

I keep a container of a mixture of leftover enamels to use for
counter enamel. Sometimes there is some leaded mixed in with the
unleaded and I have never had a problem but Thompson’s advisory makes
me wonder if this is a good idea. I’ve only used this on copper;
don’t know if that makes a difference. What do others do?

Beverly


#15

When Thompson Enamels came out with some of the first lead-free
enamels in the early 80’s I was doing large wall pieces. Every time I
used a lead-free brown over the lead-bearing enamels it would look
good for several days then it would crack and pop off. I have read,
and successfully done this, that if you use the lead-bearing over
lead-free, you won’t get the cracking. a different Donna (in VA)


#16
I keep a container of a mixture of leftover enamels to use for
cou= nter enamel. Sometimes there is some leaded mixed in with the
unleaded and I have never had a problem but Thompson's advisory
makes me wonder if this is a good idea.

You should think for yourself. If there is no problem, there is no a
problem. As for advice and experts, I read the other day in The Art
and Craft of Making Jewelry by Joanna Gollberg that it is possible to
reticulate fine silver - just heat it up and it will reticulate, no
preparation, no depletion gilding necessary (indeed if it 80’s not
even an alloy) (p.87). I wonder who the expert editors were at Lark
who let this go. Theoretically, you should use the same type of
enamel on both sides. In practice, it does not make one bit of a
difference

Leach


#17

Hi Leach,

No I have never fired the flux 10 times by itself. There could be a
difference that might apply if you were just covering copper with
flux and no enamel. I have never done that. Once I apply and fire
the flux on copper, I either use an opaque enamel which would cover
the flux or if I’m using transparents,my next firing would be silver
foil. Then I start using the colors. Or, if I’m doing cloisonne, I
add a layer of the flux directly on the silver so I have a base for
my wires. The majority of the time, I use N-3 Ninimiya flux. I never
use hard flux. Most of the transparent enamels do not look great
directly on the copper. They look beautiful silver.

That’s why I use fine silver for enameling jewelry but most of my
enamels are large pieces for the wall or a sculptural piece for a
table.

As to the cracking, could be that there was much more enamel on one
side than the other. The enamel should be the same thickness on both
sides.

Vera…All enamel manufacturers sell a counter enamel. Go to the
website for the Enamelist Society…enamelistsociety.org and you will
find a list of suppliers for all enameling “stuff”.

Donna


#18

Its not the type of enamel so much as the thickness, if you have a
2mm front you need to balance it with a 2 mm back or counter enamel,
and mixing lead and unleaded enamels in the same pot can produce some
interesting results, maybe it would be better to have 2 scrap bins
one for each that’s what I do and if you use a different colour lid
on each it is easier to remember which is which.

Anna-Margot


#19

Hi Donna, You are making me curious: why do you use a flux on the
copper if you are going to use an opaque enamel anyway? Is there a
reason?

As for transparents over flux on copper, did it never happen to you
that after several firings the copper bleeds through the enamel? I
use N-3 too. I never made a large piece.

Best, Leach


#20

The difference between silver flux and flux for copper is, most
noticeably, the color. Flux for silver has a blue tint, and flux for
copper has a yellow tint. Both can be fired over copper and, when
fired properly at the correct temperature and time, both will fire
clear. Due to the tints, they will appear different but they will
both be clear and both are usable over copper. Both work fine
beneath transparents. Test strips are always advisable to determine
which achieves your desired effect.

It is not recommended to mix leaded and unleaded enamels because of
the differences in expansion and contraction, and flow temperatures.
In my studio, I fire Thompson leaded enamels at 1400deg-1500 F,
depending on whether they are classified as “soft,” “medium,” or
"hard" enamels. In class, we have found Thompson unleaded enamels
flow at 1350 F to 1380 F. Some may need to go as high as 1400 F, but
we have found the unleaded firing temperatures to be much more
uniform than the leaded. We seldom go higher than that.
Additionally, unleaded enamels may have a larger coefficient of
thermal expansion than leaded enamels.

These differences mean that, if combined in one piece, different
layers are firing differently. One is flowing before the other. One
is fusing to the metal before the other. One is expanding more than
the other. One is contracting faster than the other. Logically, this
would indicate that the layers might not bond and would separate or
crack off entirely. I have never actually had this happen because
logic tells me it should and I cannot see any reason to spend time
creating a beautiful piece and possibly have this happen. So, I
don’t mix leaded and unleaded on one piece.

For this reason, I don’t even advise leaded on one side of the piece
and unleaded on the opposing, counter side. Not paying attention to
these properties even if you are uniform in your choice - only
leaded or only unleaded - can present problems. You must also be
uniform in choosing the expansion, contraction, and melting points
of the counter enamels.

As for not having problems with a mixture of leaded and unleaded
counter enamel, it would seem that mixing the grains of many
different enamels with many different qualities evidently works
because it averages out the effects. This would be the basis for
most counter enamels. (You can actually change the flow point/firing
temperature of flux by mixing two with different firing
temperatures). If you are choosing a specific color for the back of
your piece, you need to be more careful. For instance, I have found
that black, leaded or unleaded, does not work well unless enamel
already exists on the front of the piece. In today’s market, counter
enamel costs the same as any other enamel. You can make your own by
tossing the leftover enamel from each finished project into a common
container. Once contaminated, you don’t want to use it in another
project anyway. When doing so, it really isn’t difficult to maintain
one container for leaded counter enamel and one container for
unleaded. It is so much faster and easier to do things carefully
from the start instead of having to correct problems later.

Marilyn