Silver Glass Gone Bad

[daisydog7]

I am using a new kiln and have been having problems with silver glass. I can stick beads into the kiln that are all metallic and shiny, like Psyche, and then when I take them out, they look like Moretti 064. Or DH Helios goes in all glowing and gold, and comes out gold on one side and transparent champagne on the other. Bronze frit comes out speckled black. I've tried adding about 1/4 teaspoon of activated charcoal.... and got what I just described. I never had a bit of trouble with my old kiln. What is wrong? Thanks for any suggestions, Pam

[Elizabeth Beads]

What is your annealing schedule? Also, the new kiln may be hotter than the display says, you may need to test it (with a pyrometer?)

[daisydog7]

I have it set at 950, anneal one hour. Same as the old kiln. I think you're right, I need a pyrometer. Do you know where to get one?

[Elizabeth Beads]

Try lowering it to 925 for silver glass and hold for 1.5 hours.

[RSimmons]

You can get a pyrometer at Rio.

http://www.riogrande.com/MemberArea/...setname=703099

It's always a good idea to keep up with the accuracy of your temp settings and readout with a separate device.

You might also consider placing a small (1/2 tsp) of activated charcoal in a steel bowl in your kiln with you silver glass to prevent your coatings from oxidizing in the kiln atmosphere.

Robert

[*Naos*]

I anneal all my glass now at 920 and that seems to take care of the silver glass and the regular 104 just fine, just hold it a little longer at that temp - like 1.5-2 hours.

[smcgypsea]

you may be able to get a pyrometer at your local ceramics supply, i only paid like $80 for an analog unit.

[daisydog7]

I already use activated charcoal... maybe not enough? Probably 1/4 teaspoon. I'll get a pyrometer and try 920 for 2 hours. I'm getting desperate, I'd stick a bag of charcoal in if it'd do the trick! And some beads do fine, while others don't at all. No rhyme nor reason.

[Hayley]

How far is your thermocouple sticking out? It sounds like there may be hot spots in your kiln that is erasing the reducing effects. When you get your pyrometer, check different areas inside your kiln to see if it's consistent in temp.