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Pits and bubbles in my enamel


#1

I am having problems with pits and bubbles in my enamel. Does anybody
know where the pits and bubbles come from?


#2

this can happen if your enamel is too wet and the kiln is too hot


#3

Its mainly due to temperature To explain the principles further, You
need to get the enamel to melt fluid enough for trapped air to bubble
out.

Now how hot you need get it will depend on wether your using hard
medium or soft enamels.

which one is correct to use will depend on what metal your
enamelling on AND, wether its something thats been soldered together.
So for sterling silver thats been fabricated you should use soft
enamels. On say a flat copper disk you can use any of the 3 grades.
enamelling is technical. ie you need to get the process correct for
the product.

I enamelled for some 10 yrs before moving on to only metal work…
Went to Schauer. et Cie in Vienna, to study their products. They
made the enamels for Faberge.

Couldnt get any better than that…

So on a practical level, take your enamel, dust onto flat copper
pieces, put into your enamelling kiln and watch it through the peep
hole. When its shiny record the kiln temperature for future
reference. do this wih all your enamels.

Make a board with nails in it punch holes in your enamelled copper
strips, hang up as a reference chart, having numbered them and made
a written record of what temp each enamel met your needs. Dont be
afraid to experiment with over heating the test strips. youl learn a
lot from all this preliminary work.

Then maybe youll get the superb results we can all get. And on a
final note, I did achieve the transparent clarity that Faberge had on
his easter eggs. the only colour I couldnt get directly on silver was
a transparent ruby red. Had to go on to gold.

Then its stunning!!


#4

It sounds as if you haven’t let it dry thoroughly.

Kay Allen


#5

Pat -

First, what are you applying onto? If it’s brass, then stop. It’s
probably the zinc offgassing through the enamel and freezing as pits
and bubbles.

If you are using copper, silver or gold, then it’s probably not your
metal…provided there were no oils or other contaminants on the
metal before you applied enamel.

The sifting method of applying dry enamel is quick and satisfying,
but tends to capture air between the grains, especially if applied
too thick. The wet-pack method can avoid bubbles IF your application
technique is good. The best way to avoid problems is make the layers
THIN, no matter if dry or wet application. Thick or sloppy
application is probably your fundamental issue.

To paraphrase the enamelist Ricky Frank, “Make your layers two
grains deep.” If you grind your own from lump, keep it more coarse
than 80 mesh (the standard Thompson enamel grind). Slightly larger
grains, only two grains deep per layer, will reduce your bubble
problem without taking much more effort.

When wet-packing, perhaps you should have a more liquid application.
Not enough water will encourage clumping of the grains and will trap
air. Don’t create too much turbulence even in a liquid application,
as it will also trap air.

If you are not already a member of Grains of Glass, I recommend you
go to the website and join. Lots of inspiration from international
enamelists, and plenty of tutorials. My teacher, Chris Hierholzer,
has a series of pictorial tutorials on torch fired enamels. His most
recent is:

http://www.ganoksin.com/gnkurl/ep7zd5

Feel free to email me offline if you have more questions,

Kelley Dragon


#6

Are you wetpacking or dry sifting? If the former, make sure the
enamel is completely dry before firing. Any moisture remaining in the
enamel can result in bubbling and pitting. If dry sifting, your
enamel may be contaminated.

Marla


#7

Are you kiln firing or torch firing? If torch firing, you’re firing
too hot.

Mary


#8

Dirt contamination of the metal or the enamel is the most common
cause. The Enamelist Society conference will be in Aug. 2013.
Marianne Hunter