Annealing Silver Glass
Annealing Silver Glass
I have seen a lot of beadmakers complain that the colors on their beads going into the kiln are completely different than the colors coming out. Your kiln environment is the culprit.
Let’s talk about reducing silver glass first - for that’s an easier solution. If the luster iridescence on your beads disappears after annealing, your kiln has an oxidizing atmosphere. Try one or both of the following::
• your kiln has an oxidizing atmosphere, adding a small pea size piece of charcoal will alter the environment enough to eliminate this problem
• lower your annealing temperature – 10F/6C each time until the reducing silver glass retains its iridescence (see below for more information)
As for striking silver glass, if your beads come out dark brown, your beads have been re-struck in the kiln. These may be the reasons:
• Your temperature is re-striking the beads.
• If you have a kiln that has a short interior height (4-5 inches/10cm) and your beads are situated very close to the heating elements especially if they are elevated on a rack. Every time your kiln ramps up to the pre-set temperature, it goes full power which may lead to re-striking your beads.
Do a series of tests over a few sessions by lowering your annealing temperature 10F/6C each time until a spacer bead made with striking silver glass no longer re-strikes in your kiln. I find that for my kiln, it’s 920F/495C. When Terra first came out, Double Helix recommended annealing Terra at 930F/499C. Just make sure that you soak longer to compensate for the lower temperature (e.g. instead of 30 minutes, soak for an hour).
To ensure best results, work on unencased striking silver glass beads at the end (last hour or two) of your session.
Garaging Temperature
One last thought - when you garage anneal, every time you open and close your kiln door, the temperature in your kiln spikes up to 25F/14C either direction. To make sure that your kiln does not spike pass your annealing temperature, you may consider lowering your garaging temperature as well. For example, your kiln works best annealing at 930F/499C, then try a garaging temperature of 900F/483C.
Important note: Every kiln is different. First of all, make sure that your kiln controller is registering an accurate temperature by checking the digital controller temperature against a pyrometers (K2 pyrometer is recommended by many lampworkers). At a minimum, check your kiln at room temperature by leaving the kiln door open for about an hour and comparing that to a household thermostat.