[Enamel Bits] Enameling bowls etc

Hello again,

Without Eileen and her interesting facts from the Thompson
Enamels workbook otherwise known as Enamel Bits I would like to
explore some other areas of interest to those that enamel. I am
largely a self taught enamelist…I did take a couple of classes
where the instructor pointed to the kilns, told us not to
overheat them, and then handed us some instruction sheets and
told us to go forth and conquer. I think he probably knew quite
a bit but figured we would learn more on our own. I ended up
doing all kinds of goofy non traditional things just because I
didn’t know any different.

Now my question: I have always enameled bowls on both sides, I
assumed it was nescessary. Recently on a long car ride I read
something which mentioned that you didn’t need to enamel both
sides of bowls. I guess I can see the point to a degree but I am
a little confused, for instance: how do you keep serious fire
scale from developing on the outside of the piece and pinging off
to attach to the hot inside enamel of the bowl? Isn’t is going
to be a serious pain to clean the outside of the bowl once fired,
although I guess you could just darken it and leave it that way
for effect…anybody with any experience along these lines, or
perhaps just a good guess? I would love to hear it.

Karen in Northern Ill, where the hear has caught up to us,
serious storms last night and 97 degrees predicted today.


Hello Karen, Can’t you just wire brush the outside of the bowl
to begin the finising process? The enamel will not pop off
because the bowl is basically a dome shape. Tom Arnold

Karen, Would putting the bowl in a pickel of Sparex after
firing help clean the bowl’s outside? It might be worth a try on
a small sample. I must have taken the same class you did, so
this is only a guess. Joyce in Colorado

Dear Karen, I guess if the metal was heavy enough, warpage
wouldn’t be a problem. Fine silver of course so no firescale.
Have you read Margrete Seeler’s book Enamel as Art Medium? She
made double cups for chalices, an outer layer enameled and
counterenameled and a liner plain metal and fastened at the top
with a lip that fit over both. directions and photos in the
book show how she constructed these. Pat in hazy, hot and humid
Central PA

There is a product called “Scalex” which is available from
Thompson Enamels or Allcraft. You brush is onto the raw metal
and let it dry. Placing your piece on top of the kiln speeds
this up. After firing, the scalex falls off like thin burnt
paper. It usually has to be recoated each time the piece goes
into the kiln, but sometimes you can get away with leaving the
same coat on for a couple of firings. You can also enamel on
fine silver which doesn’t firescale.


Usually bowls are a fairly thick gauge of metal so a counter
enamel is not needed. I counter enamel because I use a thin
gauge of metal. The counter enamel on my pieces creates a
tension that is even and keeps the enamel from cracking and my
metal from warping. You didn’t mention what type of metal you
are using, but I assume it is either copper or brass, in either
case Thompson Enamel has a product that inhibits fire scale
called Scalex. .

Scalex is an excellent inhibitor for the prevention of fire
scale formation on the exposed metal surfaces as enameled items
are being fired. Paint it on thin. Let it dry. Scalex then
falls off as fired items cool, exposing a clean metal surface.
It is sold in liquid form and the cost is 10.75/pt. I have a
product called Amacote that is distributed by the American Art
Clay Co., Inc., 4717 W. 16th Street, Indianapolis, IN 46222
which I purchased from a ceramic supplier and it works just

Thompson also has some great books on enameling. Their number is

Good Luck and Happy enameling!
Linda Crawford
Linda Crawford Design, Willits, CA, USA

Now my question: I have always enameled bowls on both sides, I
assumed it was nescessary. ... you didn't need to enamel both
sides of bowls. ... how do you keep serious fire
scale from developing on the outside of the piece and pinging off
to attach to the hot inside enamel of the bowl? 

Hi Karen - While my experience is quite limited (only 2 bowls to
date - the first of which suffered a eutectic meltdown at the
very end) I can say you are quite right !! It is nearly
impossible to keep the firescale from creating floaties in the

1) Really good coats of scalex can help, but you have to redo

this every time you fire

2) Pickling your piece regularly will help, which in your case

may not be too difficult, since you are enamelling the inside of
your bowl & should be able to keep the pickle away from your
enamel. Otherwise you have to be very sure that you have a good
solid coat of enamel on the surface so that the pickel doesn’t
creep inside & get under the glass.

I recently finished reading (for the first time only) Margarete

Seeler’s book “Enamel Medium for Fine Art”. The process she
describes for doing a plique-a-jour cup involves using counter
enamel on the surface of the cup that will later be removed.
Her position is that because copper and silver both expand and
contract so much with the heat/cool down cycle, it is necessary
to use counter enamel in order to get a good surface (free of
pits and cracks) on the enamel side that is the “keeper”.

After her cup is complete, she removes the counter enamel (from

inside the cup in this case) by using an acid that will etch
away the counter enamel and not the copper. After neutralizing
the cup, she then uses a different acid to eat away the original
copper cup, leaving the net of cloisons and enamel.

Her process is really interesting, and am hoping to try it (I

have a chemist friend who has a hood I plan to use also!). The
book has much more detail & if you are interested, Email me
offline and I’ll be happy to send you more detailed excerpts
from the book itself. One other thing that I have discovered in
reading her book, is that in the classes I took to learn
enamelling, I did many more firings than I really needed to do.
I think that this was primarily because in a classroom setting,
you don’t have the luxury of keeping your work out until you
have all your wires set and/or cloisons filled before you fire
the first time. What a difference it makes! (Sometimes I’m a
little slow at these things!)

Don't figure that I've offered anything that you haven't

already done, but you do have my sympathy for the situation that
you have !!

Laura Wiesler
Towson, Md  -- Really hot and humid this week and because my 

house is being painted and is open, I don’t have A-C on…

Karen, I have found that bowl forms, even if rather shallow,
can pop the enamel when not treated gently if not counter
enameled. If you didn’t counter enamel and put the copper side
into acid or Sparex to clean, be sure that you are not using
Thompson’s lead bearing enamels in blue since they whill fog up
if they come in contact with acid. The new lead-free enamels
can take a mild acid/Sparex bath with no problem.

Donna in WY

its blue, it dries light blue, oh yeah its called “scalex” have
to reapply every firing i think but it should prevent oxidation
of the outer surface. you could also fire soft fusing flux on the
outside its clear… Robb. (thanks to Jim Malenda if he’s out
there anywhere)

Hi folks,

I should have been more clear. I know all about Scalex, I use it
during my firing of counterenamels. But I havn’t found that the
newer formula applies evenly enough for me to avoid having some
of if flake or pop of…and sometimes this can happen while the
enameled side of the piece is still hot enough to be affected by
the flakes. They say the new formula is “almost exactly” the
same, maybe it’s my memory thats changed.



I don’t use sparex to pickle copper after enameling it eats
certain colors op. black for instance. I use lemon juice and
salt the way my granny taught me to clean copper.