Hello again Sarah
most 9 carat gold contains a proportion of zinc (I was told up to 9%)
which apparently vapourises in the kiln, thereby pinging off the
enamel or at least causing pits in the surface which trap air and
ping off. This would make the fine wires jump out. Use as high carat
gold cloisonne wire as you can get hold of (23 /24) or use fine
18 carat though has worked for me as castings (Niagara Falls
Castings UK are FABULOUS - no connection, just very satisfied
customer) as long as the castings are under inert gas which avoids
porosity. Sand castings and those done in air don’t take enamel well
as tiny air bubbles occur.
In the UK the Guild of Enamellers is a very friendly organisation
for enamellers of all levels, and is only 20 a year membership.