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