I just started cleaning some beads that I'd batch annealed. Out of 10 or so beads 8 had small silver marks on the surface and tiny dents where the marks were. I don't know if they were like that before annealing. Any ideas what has caused it? The base beads are white and I've used fucshia frit. The two thoughts I had were either that they were a bit too hot when I put them in the vermiculite and some has stuck, or there might have been some bits of bead release on them that has melted into the glass in the kiln.
I've made some more exactly the same, waited a little longer before putting them in the vermiculite and they are currently off mandrel but soaking in water to make sure that there is no release on the surface before I anneal them tomorrow.
my guess would be vermiculite - happened to me when I was using that before the kiln
Sounds like the vermiculite. Just make sure that all the glow from your bead has gone before you put it into the vermiculite - that should avoid the problem as it then should be hard and cool enough not to pick up the grains of the vermiculite.
If it hadnt have dented, i would have wondered if your frit was reducing a bit. I've never used fushia frit but rubino has a habit of reducing and leaving silvery specs if the flame isnt oxygen rich.
What Claire said!! Are they tiny dents, or is the surface pitted? Could be just the frit.
They are tiny dents and each dent has a little silvery mark in it. I've got more of the same style that I made yesterday and they look ok, so I think you guys are right. I'll anneal them later and see what happens :)