There seems to be some confusion about porcelain media. There are
two types - one for polishing - the sunsheen media is one example.
The other type of media using porcelain is an abrasive - usually
incorporating silicon carbide as the cutting agent. Porcelain
simply refers to the stuff that is impregnated with abrasive
particles.
To answer your question about why the sunsheen media needs to be
broken in, the media even though apparently smooth, needs to be much
smoother. To accomplish that, you run the sunsheen or any other
burnishing porcelain media for several days in a closed, wet tumbler
with some metal. You need to check daily that it is still wet.
This is one time that flow thru doesn’t help - just use a bit of
soap to make the stuff move. It will self polish in the 4 to seven
days. You can use medium to largish pieces of silver, about 20 to
25% of the mix. Even though you condition the media with silver, it
will put a beautiful polish on gold.
Judy Hoch, GG