Sunday, April 5, 2009

Silver Glass 101 – Annealing Temperature for 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 iridescence on your beads disappear after annealing, you may choose to do one of the following, or both:
• 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.

Lower 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).

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 pyrometers 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.

6 comments:

stephanie handermann said...

Wow, i cannot believe i am the first to comment on this great piece of info!!! Thanks Hayley, i appreciate the time and effort it takes to help us gain the confidence we need in the land of silver glass!!!
Steph

enVision said...

Thank you, Steph!

~Hayley

Deronda said...

I should comment. I have used this more than once in discussions about annealing silver glass. Thank you so much for the info.

enVision said...

Good to know, Deronda! And glad to help. ;)

Lisa researching silver glass said...

Most definitely bookmarking this article for future reference. Thanks!

Annealing Glass said...

Great post! Been reading a lot about different glass working techniques lately. Thanks for the info!